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Viral and host proteins involved in picornavirus life cycle


Picornaviruses cause several diseases, not only in humans but also in various animal hosts. For instance, human enteroviruses can cause hand-foot-and-mouth disease, herpangina, myocarditis, acute flaccid paralysis, acute hemorrhagic conjunctivitis, severe neurological complications, including brainstem encephalitis, meningitis and poliomyelitis, and even death. The interaction between the virus and the host is important for viral replication, virulence and pathogenicity. This article reviews studies of the functions of viral and host factors that are involved in the life cycle of picornavirus. The interactions of viral capsid proteins with host cell receptors is discussed first, and the mechanisms by which the viral and host cell factors are involved in viral replication, viral translation and the switch from translation to RNA replication are then addressed. Understanding how cellular proteins interact with viral RNA or viral proteins, as well as the roles of each in viral infection, will provide insights for the design of novel antiviral agents based on these interactions.


Picornaviruses are a large family of animal viruses, which are pervasive in nature. Certain members of this family are well known since they importantly affect human health. The family Picornaviridae consists of five genera - enteroviruses, rhinoviruses, cardioviruses, aphthoviruses, and hepatoviruses. Picornaviruses are small icosahedral particles containing a single-stranded plus sense RNA genome with approximately 7,500 nt in length. It contains a 3' poly(A) tail with a variable length from 65 to 100 nt. The viron RNA has a virus-encoded peptide, VPg, attached at its 5' terminus, but this protein is rapidly lost in the cell and most of the viral transcripts consequently lack it [1, 2]. The picornavirus RNAs lack the cap structure (m7GpppN, where m is a methyl group and N is any nucleotide). The viral RNA encodes a single large polyprotein which undergoes a series of processing events, mediated by virus-encoded protease, to produce the mature virus proteins (including 11 mature proteins plus numerous partially processed products, depending on the virus). Four of these proteins (VP1-VP4) constitute the virus capsid, and the others participate in virus replication [3] (Fig. 1).

Figure 1

Schematic of the enterovirus genome, the polyprotein products and their major functions. A diagrammatic representation of the enterovirus genome is shown. The 11 mature polypeptides are shown, together with the three main cleavage intermediates. The main biological functions are included for each polypeptide. UTR, untranslated region; IRES, internal ribosome entry site; VPg, viral protein genome-linked.

The infection of cells by enterovirus is an efficient and productive event. To complete the life cycle of the virus, viral proteins are involved in viral replication and translation, in addition to altering host functions, such as cellular gene expression, protein localization, signal transduction and membrane rearrangement. This review focuses on the functions of viral and host factors involved in the life cycle of picornaviruses.

Host factors and capsid proteins involved in receptor binding

The capsid proteins of picornaviruses are encoded by the P1 region of the genome, and the capsid particles comprise 60 copies of four P1-encoded polypeptides, VP1 to VP4. The first three viral proteins (VP1-VP3) reside on the outer surface of the virus, and the shorter VP4 is located completely on the inner surface of the capsids. The capsid proteins mediate the initiation of infection by binding to a receptor on the host membrane. Many picornaviruses have similar receptor molecules that are members of the immunoglobulin superfamily (IgSF), whose extracellular regions comprise two to five amino-terminal immunoglobulin-like domains. For example, poliovirus receptor (PVR, CD155) contains three amino-terminal domains [4]. Additionally, coxsackievirus B1-B6 receptors (coxsackievirus-adenovirus receptor, CAR) [5], and the receptors for coxsackievirus A21 and major-group human rhinovirus (intercellular adhesion molecule-1, ICAM-1), have two and five amino-terminal domains, respectively [6, 7]. In all of these receptors, the amino-terminal domain, D1, is involved in the binding with the conserved amino acid residues of the picornavirus canyon, which can trigger viral instability and uncoating. Therefore, a single receptor suffices for virus entry, especially for poliovirus and rhinovirus [8]. However, some viruses can use non-IgSF cell surface receptors that bind to the outside of the canyon. For example, the low-density lipoprotein receptor (LDL-R) is used by the minor-group of rhinoviruses [9], and the decay-accelerating factor (DAF or CD55) binds to some echoviruses and group B coxsackieviruses [5, 10]. Human P-selectin glycoprotein ligand-1 and scavenger receptor B2 are cellular receptor for enterovirus 71 [11, 12]. Furthermore, foot-and-mouth disease viruses can attach to integrin αvβ3 or heparin sulfate, as determined by the cell lines and the virus isolates [13, 14]. These interactions, however, do not cause viral instability or uncoating, but probably result in the aggregation of other receptors, or trigger the subsequent endocytosis. For example, coxsackievirus B3 (CVB3) recruits CAR to the site of infection by binding to a second receptor DAF that is expressed in the epithelial cells [5]. Also, coxsackievirus A21 binds DAF for entry into cells only in the presence of a coreceptor, ICAM-1 [6]. Indeed, receptor recognition is important in determining the tropism of the cell and host range. However, the interaction of capsid proteins with intracellular host factors is also significant. For example, VP2 of CVB3, but not VP2 of other picornaviruses, may specifically bind to proapoptotic protein Siva, and affect the induction of apoptosis, viral spread, and the pathological process of CVB3-caused disease [15]. As will be discussed below, factors other than virus-receptor interaction, including cellular factors (such as polypyrimidine tract-binding protein, PTB) and viral genome elements (such as internal ribosome entry site, IRES), both interact with the 5' untranslated region (5' UTR) and thus influence the efficiency of translation initiation and virus replication.

Viral proteolytic activities influence cellular functions

Leader, 2A and 3C proteases (Lpro, 2Apro and 3Cpro) are picornavirus-encoded proteases, and are important for viral polyprotein processing [1618]. Lpro is present only in aphtovirus and cardiovirus-infected cells. Viral proteases not only cleave viral polypeptides, but also inhibit various host machineries.

Picornaviral 3Cpro can reportedly enter nuclei through its precursor 3CD' or 3CD, which contains a nuclear localization sequence (NLS) [19, 20]. 3Cpro can cleave numerous factors and regulators that are associated with cellular DNA-dependant RNA polymerase I, II and III, such as TATA-box binding protein (TBP), octamer-binding protein (OCT-1), transcription activator p53, cyclic AMP-responsive element binding protein (CREB), histone H3 and DNA polymerase III [2126]. 3Cpro may be involved in the virus-induced blockage of host transcription. 2Apro reportedly cleaves TBP in-vitro, but cannot inhibit cellular transcription [27].

2Apro and Lpro cleave eIF4GI and eIF4GII, 3Cpro cleaves eIF4AI, which lead to the shut off of host translation [2832]. The cleavages of Poly(A) binding protein (PABP) by 2Apro and 3Cpro also contributes to the inhibition of cellular translation [33, 34]. Furthermore, EMCV 2A protein without a catalytic function reportedly associates with 40S ribosome subunit, suggesting another mechanism of host translation shut off [35].

Numerous cytoskeleton-associated factors are cleaved in virus infection. 3Cpro cleaves microtubulin-associated protein 4 and 2Apro cleaves cytokeratin 8, which may be associated with the virus-induced cytopathic effect [36, 37]. 2Apro of enteroviruses, such as the coxsackievirus B group cleaves dystrophin protein, which may be the factor leading to cardiomyopathy [3840]. Additionally, 2Apro and 3Cpro reportedly induce cell apoptosis via both classic and autophagy pathways [4144].

Infection by poliovirus and rhinovirus involves accumulation of nuclear proteins in cytoplasm. Several components of the nuclear pore complex were degraded in infected cells and 2Apro has been suggested to be a factor that blocks nucleo-cytoplasmic trafficking [4548].

Viral and host proteins involved in RNA replication

Picornavirus infection induces a change in host membrane permeability and the production of membranous structures, on which viral replication depends [4952]. The viral replication complex has been identified to associate tightly with virus-induced membranous vesicle [53], various replication-associated viral proteins, such as 2B, 2BC, 3A, and 3D [52, 54, 55] and host proteins (Table 1).

Table 1 Cellular proteins involved in picornaviral RNA replication


Viral protein 2B and its precursor 2BC have been suggested to be responsible for membranous alteration in infected cells [5660]. The cellular proteins of COPII have reportedly been used in the virus-induced production of vesicles [61]. 2B and the precursor 2BC contain two hydrophobic regions, which are α amphipathic a-helix domain, which is important in multimerization, integrating into the membrane of the host Golgi and ER complex, producing virus-induced vesicles, and forming the virporin complex [60, 6264]. The accumulation of 2B or 2BC proteins on Golgi changes the permeability of plasma membrane [56, 62] and the disassembly of Golgi complex [65], causing cell lysis [57]. The membrane that integrates the 2B/2BC complex also reduces the Ca2+ level in ER and Golgi complex by increasing the efflux of Ca2+ [57]. The disruption of Ca2+ homeostasis by 2B/2BC is the mechanism why the transport of protein from ER to Golgi is blocked [58, 59, 66, 67]. The 2B-induced intracellular Ca2+ imbalance is also related to the anti-apoptosis property [68]. Hepatitis A virus 2B protein can reportedly inhibit cellular IFN-β gene transcription by blocking the activation of the interferon regulatory factor 3 (IRF-3), which has been suggested to be crucial to the survival of the virus [69].


Protein 3A, a membrane binding protein, plays a role in inhibiting cellular protein secretion and mediating presentation of membrane proteins during viral infection. The expression of poliovirus 3A protein in cells disrupts ER-to-Golgi trafficking, which is also observed in poliovirus 2B-expressing cells [58, 65, 70]. Moreover, the interference of protein trafficking by 3A is caused by the redistribution of ADP-ribosylation factor (Arf) family, which are important components of the membrane secretion pathway [71]. The cycling of Arf proteins between active GTP-bound and inactive GDP-bound forms are mediated by guanine nucleotide exchange factors (GEFs) and Arf GTPase-activating proteins (GAPs) [72]. Brefeldin A (BFA), a metabolite from fungus, blocks protein trafficking from ER to Golgi in cells by inhibiting the regeneration of Arf-GTP from Arf-GDP [73]. BFA can also inhibit the replication of poliovirus, implying the participation of Arf proteins in viral RNA replication [7476]. During poliovirus infection, the Arf family is involved in vesicle formation from various intracellular sites through interacting with numerous regulatory and coat proteins, and translocating to the site of viral RNA replication [71]. Two individual viral proteins, 3A and 3CD, can recruit Arfs to bind to membranes via different mechanisms [77, 78]. The expression of 3A results in the recruitment of Arfs to membranes by specifically recruiting the cellular GEF, and Golgi-specific brefeldin A resistance factor 1 (GBF1). However, synthesis of 3CD causes other GEFs, Brefeldin A-inhibited guanine nucleotide exchange factor 1 (BIG1) and BIG2, to associate with membranes [77].


According to biochemical data, the 3AB protein is a multifunctional protein. The hydrophobic domain in the 3A portion of the protein associates with membrane vesicles [79, 80]. This interaction is believed to anchor the replication complex to the virus-induced vesicles. Recombinant 3AB interacts with poliovirus 3D and 3CD in vitro [81]. The membrane-associated 3AB protein binds directly to the polymerase precursor 3CD on the cloverleaf RNA of the poliovirus, stimulating the protease activity of the 3CD, and may serve as an anchor for 3D polymerase in the RNA replication complexes [82]. Adding 3AB stimulated the activity of poliovirus 3D polymerase in vitro [83]. Furthermore, 3AB has been demonstrated to function as a substrate for 3D polymerase in VPg uridylylation [84]. The 3AB protein, rather than 3B (the mature VPg), has been proposed to be delivered to the replication complexes for VPg uridylylation. Poliovirus 3AB exhibits other functions, such as helix destabilization, revealing that 3AB has the nucleic acid chaperon activity in destabilizing the secondary structures of RNA and enhancing the hybridization in complementary nucleic acids in viral replication [85].


The enteroviral and rhinoviral 3B proteins (VPg) are small peptides, containing 21 to 23 amino acids, which are covalently linked with the 5' termini of picornavirus genome via a 5' tyrosyluridine bond in the conserved tyrosine residue in the VPg. VPg has been shown to interact with poliovirus 3D polymerase, which incorporates UMP in VPg, yielding VPgpU and VPgpUpU [86]. These products are observed in both poliovirus-infected cells and crude replication complex extract [87]. The uridylylated VPg is utilized as a primer in both positive- and negative-strand RNA synthesis [88].


3CD protein, i.e. the precursor of mature 3C protease and 3D polymerase, exhibits protease activity but no polymerase activity [89]. 3CD is capable of processing the poliovirus P1 precursor region [90]. Poliovirus 3CD contributes to viral RNAreplication by circularization of the viral genome via interacting with both 5' and 3' ends of viral RNA [91]. The cellular poly(rC) binding proteins (PCBPs), involved in viral IRES-driven translation, is also identified in the ribonucleoprotein complex, which contains 3CD and have a stem-loop I structure at the 5' end of the poliovirus genome [92, 93]. PCBPs contain four isoforms (PCBP 1-4) in mammalian cells, but only PCBP1 and 2 have been found to be involved in enterovirus replication [92, 93]. PCBP1 and 2 are KH domains RNA-binding proteins, which are involved in the metabolism of cellular mRNAs in normal cells. PCBP2 binds to both poliovirus stem-loop I and IRES, whereas PCBP1 has a binding affinity only for stem-loop I [94, 95]. The addition of recombinant PCBP1 rescues viral RNA replication in PCBP-depleted extracts, but does not rescue viral translation [95]. Another cellular protein, heterogeneous nuclear ribonucleoprotein K (hnRNP K), interacts with stem-loops I-II and IV of the EV71 5' UTR. During EV71 infection, hnRNP K was enriched in the cytoplasm where virus replication occurs, whereas hnRNP K was localized in the nucleus in mock-infected cells. Viral yields were found to be significantly lower in hnRNP K knockdown cells and viral RNA synthesis was delayed in hnRNP K knockdown cells in comparison with negative-control cells treated with small interfering RNA [96]. Moreover, 3CD has been shown, using the pull-down assay, to interact with heterogeneous nuclear ribonucleoprotein C (hnRNP C) [97]. The hnRNP C participates in pre-mRNA processing in normal cells. The mutant form of hnRNP C with the defective activity in protein-protein interaction inhibits the synthesis of viral positive-strand RNA, implying the participation of hnRNP C in RNA replication [97]. The interactions of 3CD with these cellular proteins, PCBP, hnRNP C and the viral protein, 3AB, together with the stem-loop I structure of poliovirus, form important complexes in viral RNA replication [98]. Several other cellular proteins have been reported to interact with 3CD. For example, the eukaryotic elongation factor EF-1α, one such cellular cofactor, can interact with the poliovirus 3CD-stem-loop I complex [91]. The transcription factor OCT-1 and the nucleolar chaperone B23, have also been identified as co-localizing in nuclei with HRV-16 3CD during virus infection [19]. Additionally, the recombinant mature HRV-16 3C can cleave OCT-1 in vitro. The mature 3C from the precursor 3CD may play a role in shutting off host cell transcription in nuclei. As well as exhibiting protease activity, 3CD interacts with viral RNA structures, the stem-loop I, 3' UTR and the cis-acting replication element (cre) motif of poliovirus RNA, which is the template for VPg uridylylation [9193, 99, 100].


The viral RNA-dependent RNA polymerase 3D is one of the major components of the viral RNA replication complex. The purified poliovirus 3D polymerase from the complex exhibits elongation activity [101]. 3D polymerase can also uridylylate VPg and use VPg-pUpU as a primer during viral RNA replication [86, 102]. The polymerase-polymerase interaction of poliovirus has been observed in biochemical and crystal structure studies [81, 103, 104]. The polymerase oligomerization has been proposed to be responsible for efficient template utilization. The host protein, Sam68, was identified as interacting with poliovirus 3D using a yeast-two hybrid system [105]. This interaction has also been observed in poliovirus-infected cells. Sam68, an RNA binding protein, mediates alternative splicing in cells in response to an extracellular signal. The details of the functions of Sam68 in virus RNA replication need to be demonstrated.

cis elements involved in RNA replication

The RNA secondary structures in the viral genome play important roles in the replication of viral RNA. The cis elements contain stem-loop I at the 5' terminus of 5' UTR, 3' UTR and poly(A) tail at the 3' terminus of enterovirus RNA. The circularization of the poliovirus template between the 5' and 3' termini of the viral genome is crucial during the initiation of both positive and negative-strand RNA replication [106, 107]. The 3CD and PCBP2 on stem-loop I at the 5' terminus of 5' UTR and poly(A)-binding protein (PABP) and 3CD on the 3' termini of genome are involved in the circularization of RNA genome for initiation of negative-strand RNA synthesis [106]. The enterovirus 3' UTR serves as the initiation point of negative-strand RNA synthesis. The 3CD or 3D has the ability for the interaction with the 3' UTR element [91]. The binding of 3CD and 3AB to 3' UTR does not depend on the interaction with host proteins and suffices for viral RNA replication in vitro [91]. Moreover, many works have reported that host proteins can bind to the 3' UTR of rhinovirus and enterovirus [91, 108, 109]. Nucleolin, a nuclear factor, which accumulated in the cytoplasm of poliovirus-infected cells, interacted strongly with an intact 3'-UTR of poliovirus in vitro [110]. The immunodepletion of nucleolin from cell-free extract reduced virus reproduction, indicating that nucleolin may be involved in viral RNA replication. The 3' stem-loop I of the negative-strand RNA is the initiation site of positive-strand RNA synthesis. Positive-strand RNA synthesis is initiated by the recruitment of uridylylated VPg-containing replication complexes close to the 3' stem-loop I of the negative strand. Viral protein 2C has been reported to interact directly with the 3' stem-loop I of the negative strand [111]. The cellular protein, hnRNP C, which specifically interacts with either the 3' end of the poliovirus negative-strand RNA or the protein 3CD, is involved in positive-strand RNA synthesis, and probably in the initiation step [97]. Some cellular proteins, such as La, can interact with both 3' and 5' UTRs of CVB3 independently of the poly(A) tail, and may play a role in mediating cross-talk between the 5' and 3' ends of CVB3 RNA for viral RNA replication [112].

Synthesis of the uridylylated VPg is the first step of viral RNA synthesis. The efficient uridylylation of VPg requires 3D polymerase, 3CD protein, UTP and the cre motif from the viral genome as the template. 3CD has been shown to stimulate cre-mediated VPg uridylylation [102]. Moreover, the 3AB protein is regarded as the precursor of VPg (3B) in the RNA replication complex for VPg uridylylation [84]. The cre motif was identified in different regions of the enterovirus genome. The cre structures are located in the 2C-encoding region of poliovirus, the capsid-encoding region of human rhinovirus 14 and cardiovirus, the 2A-encoding region of human rhinovirus 2, the 5' non-coding region of the foot-and-mouth disease virus, and the 3D-encoding region of the hepatitis A virus [113118].

Switch from translation to RNA replication

The positive-stranded RNA viruses use the same RNA as a template for translation and replication. Ribosomes move from the 5' end to the 3' end of RNA to undergo translation, and RNA polymerase binds to the 3' end of the same RNA to initiate replication. In vitro experiments have demonstrated that using cycloheximide to freeze ribosomes on translated RNAs inhibits RNA replication, while using puromycin to release the ribosomes allows facilitates RNA replication [119]. These two events cannot occur at the same time, so the balance between translation and replication is important.

The poliovirus genome contains a conserved 5' UTR, which is important to translation and RNA replication [120]. Gamarnik and Andino have suggested that the binding of 3CD to the cloverleaf at the 5' end of the viral genome promotes the replication of RNA, rather than its translation [121]. Furthermore, they found that PCBP2 binds to stem-loop IV in poliovirus translation. When newly translated 3CD binds to stem-loop I RNA, the affinity of PCBP2 binding for the same region is increased. 3CD induces the dissociation of PCBP2 from stem-loop IV because the affinity of PCBP2 for stem-loop I is increased, while that for viral translation is reduced [98].

Semler et al. found that proteases 3C/3CD cleave PCBP1 and 2 during the mid-to-late phase of poliovirus infection. The primary cleavage site is between the KH2 and KH3 domains. The cleaved PCBP2 cannot bind to stem-loop IV and it loses functionality in translation. However, the cleaved PCBP2 still binds to stem-loop I and mediates the replication of viral RNA. PCBP2 can mediate the switch from viral translation to RNA replication [122].

Host factors and viral proteins involved in picornaviral IRES-mediated translation

Most picornaviral IRESs are divided into four classifications based on homology, secondary structure, and other properties (Fig. 2). Type I IRESs include those of poliovirus, rhinovirus, coxsackievirus, and other enteroviruses. Type II IRESs include those of the foot and mouth disease virus (FMDV), cardiviruses such as encephalomyocarditis virus (EMCV), paraechoviruses and kobuvirus. Type III IRESs include the hepatitis A virus (HAV). The newly classified teschovirus IRES is the most similar to hepatitis C virus, which is not a picornavirus, and so may represent an ancient recombinant event between an enterovirus and hepacivirus or pestivirus [123].

Figure 2

Structural features of type I, II, III, and IV picornavirus IRES elements. RNA secondary structures of four types base on M-fold software. (A). Enteroviruses (PV, CVB3 and EV71) and rhinoviruses contain type I IRES elements. (B). Aphthoviruses (FMDV) and cardiovirus (EMCV and TMEV) contain type II IRES elements. (C). HAV contains type III IRES element. (D). porcine reschovirus serotype 1 (PTV-1) contains type IV IRES element.

IRES-mediated initiation may require both canonical initiation factors and IRES trans-activating factors (ITAFs) that are not involved in cap-mediated initiation. ITAFs are cellular proteins that are not involved in normal cap-dependent translation but facilitate cap-independent translation. Different viral IRESs have different ITAF requirements, although several are shared. ITAFs may serve as IRES chaperones, binding to RNA across multiple domains and stabilizing the entire IRES in a configuration that is appropriate for binding canonical translation factors, and ultimately ribosomes (Table 2) [124].

Table 2 Cellular proteins involved in picornaviral IRES-mediated translation

Canonical translation factors

PV and EMCV IRES elements are similar to capped mRNA in requiring that some initiation factors bind to primed 40S subunits and to the RNA itself. These canonical factors have been identified as eIF4G and eIF4B, which bind to the viral RNA, and eIF3 and eIF2, which must prebind the 40S subunit. Furthermore, poly(A)-binding protein substantially promotes the IRES-mediated translation of EMCV and PV. This rather high requirement of picornaviral IRESs for canonical translation factors is in contrast to that of IRES elements of other viruses, such as hepatitis C virus and the cricket paralysis virus, which require few or no translation factor to bind to the ribosome [125].

Noncanonical translation factors

Polypyrimidine tract-binding protein (PTB)

PTB (also known as p57 and hnRNP I) is a member of the hnRNP family and shuttles between the nucleus and the cytoplasm in a transcription-sensitive manner [126]. PTB is a 57 kDa mRNA splicing factor and has four RNA recognition motifs (RRMs). PTB was identified originally as a protein that binds to the polypyrimidine tracts (Py tracts) of adenoviral major-late and α-tropomyosin pre-mRNAs, and has been proposed to be a splicing factor [127]. The binding of PTB to the Py tract close to the branching point of intron has been demonstrated to modulate the alternative splicing of certain pre-mRNAs [128]. Independently, PTB was shown to interact specifically with the IRESs of numerous picornaviruses [129, 130], including poliovirus [131, 132], FMDV [133], EMCV [134], Theiler's murine encephalomyelitis virus (TMEV) [135], and HAV [136, 137].

Experiments on the depletion and repletion of PTB from rabbit reticulocyte lysate (RRL) have revealed that the efficient translation of FMDV mRNA and a mutant EMCV mRNA depends on PTB [133, 134]. Intriguingly, PTB is required for the translation of a mutant EMCV mRNA, but not wild-type EMCV [138], suggesting that PTB is involved in maintaining the proper conformation of the mutant EMCV IRES [138]. Supplementation of RRL with PTB enhances the translation of polioviral mRNA [139, 140]. The immunodepletion of PTB from HeLa cell lysate inhibited poliovirus IRES-dependent translation. Repletion of purified PTB to the immunodepleted lysate did not restore poliovirus IRES-dependent translation. This investigation suggested that the depletion process may have removed unidentified translation factors [132]. The effect of PTB on poliovirus IRES-dependent translation was examined using artificial dicistronic mRNAs that contain the PTB gene as the first cistron, the poliovirus IRES in the intercistronic region, and the chloramphenicol acetyltransferase (CAT) reporter gene as the second cistron. When PTB was transfected into HeLa cells, which contain a limited amount of endogenous PTB, its additional expression increased the activity of poliovirus IRES by 2.5-fold [141]. These results suggest that PTB is required for, or at least promotes, the IRES activity of picornavirus.

Poliovirus protein, 3Cpro (and/or 3CDpro), cleaves PTB isoforms (PTB1, PTB2, and PTB4). PTBs contain three 3Cpro target sites (one major target site and two minor target sites). PTB fragments that are produced by PV infection are redistributed to the cytoplasm from the nucleus, where most of the intact PTBs are localized. Additionally, these PTB fragments inhibit poliovirus IRES-dependent translation in a cell-based assay system. The authors posit that the proteolytic cleavage of PTBs may contribute to the molecular switching from translation to the replication of polioviral RNA [142].

PV-attenuated type 3 Sabin and virulent type 3 Leon viruses translated equally well in HeLa cells, but the translation of the attenuated Sabin virus is restricted in neuroblastoma cells. The C472-to-U mutation in the IRES caused the translation defect. Comparison of IRES between Leon serotype 3 and Sabin serotype 3 PV revealed that PTB and a novel neural-cell-specific homologue of PTB (nPTB) were bound adjacent to the attenuation mutation in domain V, but binding was less efficient on the Sabin IRES. The Sabin IRES was demonstrated to have a translation defect in chicken neurons that can be rescued by increased PTB expression in the CNS [143].

PTB has also been shown most clearly to function as an RNA chaperon, stabilizing the type II IRESs, such as EMCV and FMDV, in an active conformation [144, 145].

Lupus autoantigen (La)

Lupus autoantigen (La) is a 52 kDa, predominantly nuclear protein. It is a target for autoimmune recognition in patients with systemic lupus erythematosus and Sjogren's syndrome. The majority of La is localized in the nucleus, and it is related to stabilization of nascent RNAs, nuclear retention of nascent transcripts, and RNA pol III transcription termination. During PV infection, La is redistributed to the cytoplasm by 3 h postinfection (p.i.) [146, 147]. This redistribution coincides with the appearance of 3Cpro in infected cells, and is caused by a 3Cpro-mediated cleavage event, which removes a nuclear localization signal from the C-terminus of La, but maintains the dimerization domain. The truncated La can still stimulate translation effectively, but is relocalized to the cytoplasm during viral protein synthesis [147]. Depletion of La from cells by small interfering RNA reduced IRES translation. Similarity, a dominant-negative mutant of La inhibited 40S ribosomal binding by PV IRES in vitro [148]. La protein also binds to the CVB3 IRES and stimulates viral translation in a dose-dependent manner in rabbit reticulocyte [149, 150]. La protein binds specifically to distinct parts of HAV IRES, and suppresses HAV IRES-mediated translation and replication by small interfering RNA in vivo and purified La protein in vitro [151].

Poly(rC)-binding protein 1, 2 (PCBP1, 2)

PCBPs are RNA-binding proteins that preferentially bind to single-stranded stretches of cytidines. Mammalian cells contain four isoforms, PCBP 1-4, but only PCBP1 and PCBP2 have been experimentally demonstrated to have roles in the life cycles of enteroviruses [93]. PCBP2 is a factor that is required for poliovirus translation and was discovered because of its interaction with stem-loop IV of the poliovirus IRES [94]. Depletion and replication studies of PCBP2 from HeLa cell-free extracts using a stem-loop RNA affinity column have revealed that PCBP2 was required for PV IRES-dependent translation [152]. Moreover, an oligo-DNA with high affinity to PCBP1 and PCBP2 was recently used to prove that both PCBP1 and PCBP2 function as ITAFs of the PV IRES [153]. PCBP2 also binds to the HAV 5' UTR and stimulates viral translation [154].

One nucleocytoplasmic SR protein, SRp20, interacts with PCBP2 and is involved in the internal ribosome entry site-mediated translation of viral RNA. Both depletion and in vitro translation studies of SRp20 from HeLa cell free extracts have shown that SRp20 is required for the initiation of PV translation. Targeting SRp20 in HeLa cells with short interfering RNAs inhibited the expression of SRp20 protein and correspondingly reduced PV translation [155].

In vitro translation reactions were performed in HeLa cell cytoplasmic translation extracts whose cellular protein, PCBP2 was depleted [156]. Upon depletion of PCBP2, these extracts exhibited a significantly reduced capacity to translate reporter RNAs that contained the type I IRES elements of poliovirus, coxsackievirus, or human rhinovirus, which is linked to luciferase; however, adding recombinant PCBP2 protein restored translation. RNA electrophoretic mobility-shift analysis demonstrated specific interactions between PCBP2 and both type I and type II picornavirus IRES elements; however, the translation of reporter RNAs that contain the type II IRES elements of the encephalomyocarditis virus and the foot-and-mouth disease virus did not depend on PCBP2. These data indicate that PCBP2 is essential for the internal initiation of translation on picornavirus type I IRES elements, but not by the structurally distinct type II elements [156].

Upstream of N-ras (Unr)

Upstream of N-ras (Unr) is a cytoplasmic protein that contains five cold-shock domains. A depletion study of Unr from reticulocyte lysate revealed that Unr was required for the translation of rhinovirus IRES [139]. Both HRV and PV IRES translation was severely impaired in unr(-/-) murine embryonic stem cells. Translation was restored by the transient expression of Unr in unr(-/-) cells [157].

Heterogenerous nuclear ribonucleoprotein A1 (hnRNP A1)

hnRNP A1, an RNA-binding protein that shuttles between the nucleus and the cytoplasm, is a member of a large group of RNA binding proteins (hnRNPs) which are classified into several families and subfamilies based on conserved structural and functional motifs. The hnRNP A1 protein is composed of 320 amino acids; it contains two RNA-binding domains and a glycine-rich domain, which is responsible for protein-protein interaction.

hnRNP A1 is an internal ribosome entry site (IRES) trans-acting factor that binds specifically to the 5' UTR of the HRV2 and regulates its translation. Furthermore, the cytoplasmic redistribution of hnRNP A1 after rhinovirus infection enhances rhinovirus IRES-mediated translation [158]. RNA-protein pull down assay, reporter assay and viral RNA synthesis assay reveal that hnRNP A1 also interacts with the 5' UTR of enterovirus 71 (EV71) and regulates viral replication [159].


ITAF45 is also known as erbB3-binding protein 1 (Ebp1) or p38-2G4, which is a proliferation-dependent protein that is distributed throughout the cytoplasm from the metaphase to the telophase. ITAF45 is a proliferation-dependent protein that is undetectable in murine brain cells and so may function as a tissue-specific factor that controls the translation of particular mRNAs. The initiation on the TMEV IRES depended strongly on PTB, where the initiation on the FMDV IRES depended on both PTB and ITAF45. ITAF45 was bound specifically to a central domain of the FMDV IRES and acted synergistically with PTB to promote the binding of eIF4F to an adjacent domain [124].


As a 110 kDa nucleolar protein, nucleolin/C23 protein is also an RNA binding protein which contains four RNA binding motifs [160]. Nucleolin is an abundant protein of the nucleolus and participates in rDNA transcription, rRNA maturation, ribosome assembly and nucleocytoplasmic transport [161]. Nucleolin/C23 has been shown to translocate into the cytoplasm following the infection of cells with PV [110]. Nucleolin/C23 stimulates PV IRES-mediated translation in vitro and rhinovirus IRES-mediated translation in vivo. Nucleolin/C23 mutants that contain the carboxy-terminal RNA binding domains, but lack the amino-terminal domains, act as dominant-negative mutants in in vitro translation assay. The translation inhibitory activity of these mutants is related to their capacity to bind to the 5' UTR sequence [162].

dsRNA binding protein76:NF45 heterodimer

The double-stranded RNA binding protein 76 (DRBP76) contains two dsRNA-binding motifs and is almost identical to M-phase phosphoprotein 4, NF90, translation control protein (TCP80), and NF associated with dsRNA. DRBP76 has been found to bind to the HRV2 IRES in neuronal cells and to inhibit PV-RIPO translation and propagation [163]. The size of exclusion chromatography indicates that DRBP76 heterodimerizes with the nuclear factor of activated T cells, of size 45 kDa (NF45), in neuronal but not in glioma cells. The DRBP76:NF45 heterodimer binds to the HRV2 IRES in neuronal but not in glioma cells. Ribosomal profile analyses have demonstrated that the heterodimer preferentially associates with the translation apparatus in neuronal cells, and arrests translation at the HRV2 IRES, preventing the assembly PV-RIPO RNA into the polysome [164].

Far upstream element binding protein 2 (FBP2)

The far upstream element binding protein 2 (FBP2) is also known as the K homology (KH)-type splicing regulatory protein (KSRP). It was originally identified as a component of a protein complex that assembles on an intronic c-src neuronal-specific splicing enhancer, and as an important adenosine-uridine element binding protein (ARE-BP) that interacts with several AREs [165, 166]. FBP2 is required for the rapid decay of several ARE-containing mRNAs both in vitro and in vivo. It contains four contiguous KH motifs that recognize the ARE, interact with the exosome, and the poly(A) ribonuclease (PARN), and promote the rapid decay of ARE-containing RNAs [167].

Biotinylated RNA-affinity chromatography and proteomic approaches were utilized to identify FBP2 as an ITAF for EV71. During EV71 infection, FBP2 was enriched in cytoplasm where viral replication occurs, whereas FBP2 was localized in the nucleus in mock-infected cells. The synthesis of viral proteins was promoted in FBP2-knockdown cells that were infected by EV71. IRES activity in FBP2-knockdown cells exceeded that in the negative control (NC) siRNA-treated cells. However, IRES activity decreased when FBP2 was over-expressed in the cells. The results of this investigation suggest that FBP2 is a novel ITAF that interacts with EV71 IRES and negatively regulates viral translation [168].

Compelling evidence suggests that cellular RNA-binding proteins (ITAFs) are involved importantly in translation from a variety of IRES elements, suggesting potential roles for RNA-binding proteins in IRES-dependent translation. First, an RNA-binding protein recruits the translational machinery via a protein-protein or protein-RNA interaction. This putative RNA-binding protein then binds directly to the ribosomal subunit, to canonical translation factors, or to a putative mediator protein that connects other RNA-binding proteins with the basal translational machinery. Second, RNA-binding proteins may serve as 'clamping proteins,' holding various parts of IRES RNA in a particular configuration. Components of the translational machinery may bind exclusively to the RNA portion of the RNA-protein complex that is maintained by these clamping proteins.

Concluding remarks

Picornaviruses use multiple RNA-protein interactions to mediate important reactions in their life cycle, including IRES-mediated translation, possible circularization of the genome, and RNA replication. The molecular mechanisms by which host factors are involved in RNA-protein/protein-protein interaction have been intensively studied; however, tissue-specific viral virulence remains unclear, and demands further investigation in the future. No information is available on whether picornaviruses can be targeted by cellular microRNAs, leading to transcriptional or translational silencing, or RNAi-mediated degradation of viral RNA. This is another field that needs to be further studied in the future.


  1. 1.

    Ambros V, Baltimore D: Purification and properties of a HeLa cell enzyme able to remove the 5'-terminal protein from poliovirus RNA. J Biol Chem. 1980, 255: 6739-6744.

    CAS  PubMed  Google Scholar 

  2. 2.

    Dorner AJ, Rothberg PG, Wimmer E: The fate of VPg during in vitro translation of poliovirus RNA. FEBS Lett. 1981, 132: 219-223. 10.1016/0014-5793(81)81164-7.

    CAS  PubMed  Google Scholar 

  3. 3.

    Stanway G: Structure, function and evolution of picornaviruses. J Gen Virol. 1990, 71 (Pt 11): 2483-2501. 10.1099/0022-1317-71-11-2483.

    CAS  PubMed  Google Scholar 

  4. 4.

    He Y, Bowman VD, Mueller S, Bator CM, Bella J, Peng X, Baker TS, Wimmer E, Kuhn RJ, Rossmann MG: Interaction of the poliovirus receptor with poliovirus. Proc Natl Acad Sci USA. 2000, 97: 79-84. 10.1073/pnas.97.1.79.

    PubMed Central  CAS  PubMed  Google Scholar 

  5. 5.

    Coyne CB, Bergelson JM: Virus-induced Abl and Fyn kinase signals permit coxsackievirus entry through epithelial tight junctions. Cell. 2006, 124: 119-131. 10.1016/j.cell.2005.10.035.

    CAS  PubMed  Google Scholar 

  6. 6.

    Shafren DR, Dorahy DJ, Ingham RA, Burns GF, Barry RD: Coxsackievirus A21 binds to decay-accelerating factor but requires intercellular adhesion molecule 1 for cell entry. J Virol. 1997, 71: 4736-4743.

    PubMed Central  CAS  PubMed  Google Scholar 

  7. 7.

    Kolatkar PR, Bella J, Olson NH, Bator CM, Baker TS, Rossmann MG: Structural studies of two rhinovirus serotypes complexed with fragments of their cellular receptor. Embo J. 1999, 18: 6249-6259. 10.1093/emboj/18.22.6249.

    PubMed Central  CAS  PubMed  Google Scholar 

  8. 8.

    Rossmann MG, He Y, Kuhn RJ: Picornavirus-receptor interactions. Trends Microbiol. 2002, 10: 324-331. 10.1016/S0966-842X(02)02383-1.

    CAS  PubMed  Google Scholar 

  9. 9.

    Hewat EA, Neumann E, Conway JF, Moser R, Ronacher B, Marlovits TC, Blaas D: The cellular receptor to human rhinovirus 2 binds around the 5-fold axis and not in the canyon: a structural view. Embo J. 2000, 19: 6317-6325. 10.1093/emboj/19.23.6317.

    PubMed Central  CAS  PubMed  Google Scholar 

  10. 10.

    Bergelson JM, Chan M, Solomon KR, St John NF, Lin H, Finberg RW: Decay-accelerating factor (CD55), a glycosylphosphatidylinositol-anchored complement regulatory protein, is a receptor for several echoviruses. Proc Natl Acad Sci USA. 1994, 91: 6245-6248. 10.1073/pnas.91.13.6245.

    PubMed Central  CAS  PubMed  Google Scholar 

  11. 11.

    Nishimura Y, Shimojima M, Tano Y, Miyamura T, Wakita T, Shimizu H: Human P-selectin glycoprotein ligand-1 is a functional receptor for enterovirus 71. Nat Med. 2009, 15: 794-797. 10.1038/nm.1961.

    CAS  PubMed  Google Scholar 

  12. 12.

    Yamayoshi S, Yamashita Y, Li J, Hanagata N, Minowa T, Takemura T, Koike S: Scavenger receptor B2 is a cellular receptor for enterovirus 71. Nat Med. 2009, 15: 798-801. 10.1038/nm.1992.

    CAS  PubMed  Google Scholar 

  13. 13.

    Berinstein A, Roivainen M, Hovi T, Mason PW, Baxt B: Antibodies to the vitronectin receptor (integrin alpha V beta 3) inhibit binding and infection of foot-and-mouth disease virus to cultured cells. J Virol. 1995, 69: 2664-2666.

    PubMed Central  CAS  PubMed  Google Scholar 

  14. 14.

    Fry EE, Lea SM, Jackson T, Newman JW, Ellard FM, Blakemore WE, Abu-Ghazaleh R, Samuel A, King AM, Stuart DI: The structure and function of a foot-and-mouth disease virus-oligosaccharide receptor complex. Embo J. 1999, 18: 543-554. 10.1093/emboj/18.3.543.

    PubMed Central  CAS  PubMed  Google Scholar 

  15. 15.

    Henke A, Nestler M, Strunze S, Saluz HP, Hortschansky P, Menzel B, Martin U, Zell R, Stelzner A, Munder T: The apoptotic capability of coxsackievirus B3 is influenced by the efficient interaction between the capsid protein VP2 and the proapoptotic host protein Siva. Virology. 2001, 289: 15-22. 10.1006/viro.2001.1082.

    CAS  PubMed  Google Scholar 

  16. 16.

    Strebel K, Beck E: A second protease of foot-and-mouth disease virus. J Virol. 1986, 58: 893-899.

    PubMed Central  CAS  PubMed  Google Scholar 

  17. 17.

    Svitkin YV, Gorbalenya AE, Kazachkov YA, Agol VI: Encephalomyocarditis virus-specific polypeptide p22 possessing a proteolytic activity: preliminary mapping on the viral genome. FEBS Lett. 1979, 108: 6-9. 10.1016/0014-5793(79)81165-5.

    CAS  PubMed  Google Scholar 

  18. 18.

    Toyoda H, Nicklin MJ, Murray MG, Anderson CW, Dunn JJ, Studier FW, Wimmer E: A second virus-encoded proteinase involved in proteolytic processing of poliovirus polyprotein. Cell. 1986, 45: 761-770. 10.1016/0092-8674(86)90790-7.

    CAS  PubMed  Google Scholar 

  19. 19.

    Amineva SP, Aminev AG, Palmenberg AC, Gern JE: Rhinovirus 3C protease precursors 3CD and 3CD' localize to the nuclei of infected cells. J Gen Virol. 2004, 85: 2969-2979. 10.1099/vir.0.80164-0.

    CAS  PubMed  Google Scholar 

  20. 20.

    Sharma R, Raychaudhuri S, Dasgupta A: Nuclear entry of poliovirus protease-polymerase precursor 3CD: implications for host cell transcription shut-off. Virology. 2004, 320: 195-205. 10.1016/j.virol.2003.10.020.

    CAS  PubMed  Google Scholar 

  21. 21.

    Clark ME, Lieberman PM, Berk AJ, Dasgupta A: Direct cleavage of human TATA-binding protein by poliovirus protease 3C in vivo and in vitro. Mol Cell Biol. 1993, 13: 1232-1237.

    PubMed Central  CAS  PubMed  Google Scholar 

  22. 22.

    Yalamanchili P, Datta U, Dasgupta A: Inhibition of host cell transcription by poliovirus: cleavage of transcription factor CREB by poliovirus-encoded protease 3Cpro. J Virol. 1997, 71: 1220-1226.

    PubMed Central  CAS  PubMed  Google Scholar 

  23. 23.

    Yalamanchili P, Weidman K, Dasgupta A: Cleavage of transcriptional activator Oct-1 by poliovirus encoded protease 3Cpro. Virology. 1997, 239: 176-185. 10.1006/viro.1997.8862.

    CAS  PubMed  Google Scholar 

  24. 24.

    Clark ME, Hammerle T, Wimmer E, Dasgupta A: Poliovirus proteinase 3C converts an active form of transcription factor IIIC to an inactive form: a mechanism for inhibition of host cell polymerase III transcription by poliovirus. Embo J. 1991, 10: 2941-2947.

    PubMed Central  CAS  PubMed  Google Scholar 

  25. 25.

    Falk MM, Grigera PR, Bergmann IE, Zibert A, Multhaup G, Beck E: Foot-and-mouth disease virus protease 3C induces specific proteolytic cleavage of host cell histone H3. J Virol. 1990, 64: 748-756.

    PubMed Central  CAS  PubMed  Google Scholar 

  26. 26.

    Weidman MK, Yalamanchili P, Ng B, Tsai W, Dasgupta A: Poliovirus 3C protease-mediated degradation of transcriptional activator p53 requires a cellular activity. Virology. 2001, 291: 260-271. 10.1006/viro.2001.1215.

    CAS  PubMed  Google Scholar 

  27. 27.

    Yalamanchili P, Banerjee R, Dasgupta A: Poliovirus-encoded protease 2APro cleaves the TATA-binding protein but does not inhibit host cell RNA polymerase II transcription in vitro. J Virol. 1997, 71: 6881-6886.

    PubMed Central  CAS  PubMed  Google Scholar 

  28. 28.

    Sommergruber W, Ahorn H, Klump H, Seipelt J, Zoephel A, Fessl F, Krystek E, Blaas D, Kuechler E, Liebig HD: 2A proteinases of coxsackie- and rhinovirus cleave peptides derived from eIF-4 gamma via a common recognition motif. Virology. 1994, 198: 741-745. 10.1006/viro.1994.1089.

    CAS  PubMed  Google Scholar 

  29. 29.

    Gradi A, Svitkin YV, Imataka H, Sonenberg N: Proteolysis of human eukaryotic translation initiation factor eIF4GII, but not eIF4GI, coincides with the shutoff of host protein synthesis after poliovirus infection. Proc Natl Acad Sci USA. 1998, 95: 11089-11094. 10.1073/pnas.95.19.11089.

    PubMed Central  CAS  PubMed  Google Scholar 

  30. 30.

    Svitkin YV, Gradi A, Imataka H, Morino S, Sonenberg N: Eukaryotic initiation factor 4GII (eIF4GII), but not eIF4GI, cleavage correlates with inhibition of host cell protein synthesis after human rhinovirus infection. J Virol. 1999, 73: 3467-3472.

    PubMed Central  CAS  PubMed  Google Scholar 

  31. 31.

    Kirchweger R, Ziegler E, Lamphear BJ, Waters D, Liebig HD, Sommergruber W, Sobrino F, Hohenadl C, Blaas D, Rhoads RE: Foot-and-mouth disease virus leader proteinase: purification of the Lb form and determination of its cleavage site on eIF-4 gamma. J Virol. 1994, 68: 5677-5684.

    PubMed Central  CAS  PubMed  Google Scholar 

  32. 32.

    Li W, Ross-Smith N, Proud CG, Belsham GJ: Cleavage of translation initiation factor 4AI (eIF4AI) but not eIF4AII by foot-and-mouth disease virus 3C protease: identification of the eIF4AI cleavage site. FEBS Lett. 2001, 507: 1-5. 10.1016/S0014-5793(01)02885-X.

    CAS  PubMed  Google Scholar 

  33. 33.

    Kuyumcu-Martinez NM, Joachims M, Lloyd RE: Efficient cleavage of ribosome-associated poly(A)-binding protein by enterovirus 3C protease. J Virol. 2002, 76: 2062-2074. 10.1128/jvi.76.5.2062-2074.2002.

    PubMed Central  CAS  PubMed  Google Scholar 

  34. 34.

    Kuyumcu-Martinez NM, Van Eden ME, Younan P, Lloyd RE: Cleavage of poly(A)-binding protein by poliovirus 3C protease inhibits host cell translation: a novel mechanism for host translation shutoff. Mol Cell Biol. 2004, 24: 1779-1790. 10.1128/MCB.24.4.1779-1790.2004.

    PubMed Central  CAS  PubMed  Google Scholar 

  35. 35.

    Groppo R, Palmenberg AC: Cardiovirus 2A protein associates with 40S but not 80S ribosome subunits during infection. J Virol. 2007, 81: 13067-13074. 10.1128/JVI.00185-07.

    PubMed Central  CAS  PubMed  Google Scholar 

  36. 36.

    Joachims M, Harris KS, Etchison D: Poliovirus protease 3C mediates cleavage of microtubule-associated protein 4. Virology. 1995, 211: 451-461. 10.1006/viro.1995.1427.

    CAS  PubMed  Google Scholar 

  37. 37.

    Seipelt J, Liebig HD, Sommergruber W, Gerner C, Kuechler E: 2A proteinase of human rhinovirus cleaves cytokeratin 8 in infected HeLa cells. J Biol Chem. 2000, 275: 20084-20089. 10.1074/jbc.275.26.20084.

    CAS  PubMed  Google Scholar 

  38. 38.

    Badorff C, Lee GH, Lamphear BJ, Martone ME, Campbell KP, Rhoads RE, Knowlton KU: Enteroviral protease 2A cleaves dystrophin: evidence of cytoskeletal disruption in an acquired cardiomyopathy. Nat Med. 1999, 5: 320-326. 10.1038/6543.

    CAS  PubMed  Google Scholar 

  39. 39.

    Badorff C, Berkely N, Mehrotra S, Talhouk JW, Rhoads RE, Knowlton KU: Enteroviral protease 2A directly cleaves dystrophin and is inhibited by a dystrophin-based substrate analogue. J Biol Chem. 2000, 275: 11191-11197. 10.1074/jbc.275.15.11191.

    CAS  PubMed  Google Scholar 

  40. 40.

    Baxter NJ, Roetzer A, Liebig HD, Sedelnikova SE, Hounslow AM, Skern T, Waltho JP: Structure and dynamics of coxsackievirus B4 2A proteinase, an enyzme involved in the etiology of heart disease. J Virol. 2006, 80: 1451-1462. 10.1128/JVI.80.3.1451-1462.2006.

    PubMed Central  CAS  PubMed  Google Scholar 

  41. 41.

    Barco A, Feduchi E, Carrasco L: Poliovirus protease 3C(pro) kills cells by apoptosis. Virology. 2000, 266: 352-360. 10.1006/viro.1999.0043.

    CAS  PubMed  Google Scholar 

  42. 42.

    Li ML, Hsu TA, Chen TC, Chang SC, Lee JC, Chen CC, Stollar V, Shih SR: The 3C protease activity of enterovirus 71 induces human neural cell apoptosis. Virology. 2002, 293: 386-395. 10.1006/viro.2001.1310.

    CAS  PubMed  Google Scholar 

  43. 43.

    Calandria C, Irurzun A, Barco A, Carrasco L: Individual expression of poliovirus 2Apro and 3Cpro induces activation of caspase-3 and PARP cleavage in HeLa cells. Virus Res. 2004, 104: 39-49. 10.1016/j.virusres.2004.02.042.

    CAS  PubMed  Google Scholar 

  44. 44.

    Chau DH, Yuan J, Zhang H, Cheung P, Lim T, Liu Z, Sall A, Yang D: Coxsackievirus B3 proteases 2A and 3C induce apoptotic cell death through mitochondrial injury and cleavage of eIF4GI but not DAP5/p97/NAT1. Apoptosis. 2007, 12: 513-524. 10.1007/s10495-006-0013-0.

    CAS  PubMed  Google Scholar 

  45. 45.

    Lidsky PV, Hato S, Bardina MV, Aminev AG, Palmenberg AC, Sheval EV, Polyakov VY, van Kuppeveld FJ, Agol VI: Nucleocytoplasmic traffic disorder induced by cardioviruses. J Virol. 2006, 80: 2705-2717. 10.1128/JVI.80.6.2705-2717.2006.

    PubMed Central  CAS  PubMed  Google Scholar 

  46. 46.

    Gustin KE, Sarnow P: Effects of poliovirus infection on nucleo-cytoplasmic trafficking and nuclear pore complex composition. Embo J. 2001, 20: 240-249. 10.1093/emboj/20.1.240.

    PubMed Central  CAS  PubMed  Google Scholar 

  47. 47.

    Gustin KE, Sarnow P: Inhibition of nuclear import and alteration of nuclear pore complex composition by rhinovirus. J Virol. 2002, 76: 8787-8796. 10.1128/JVI.76.17.8787-8796.2002.

    PubMed Central  CAS  PubMed  Google Scholar 

  48. 48.

    Park N, Katikaneni P, Skern T, Gustin KE: Differential targeting of nuclear pore complex proteins in poliovirus-infected cells. J Virol. 2008, 82: 1647-1655. 10.1128/JVI.01670-07.

    PubMed Central  CAS  PubMed  Google Scholar 

  49. 49.

    Bienz K, Egger D, Rasser Y, Bossart W: Intracellular distribution of poliovirus proteins and the induction of virus-specific cytoplasmic structures. Virology. 1983, 131: 39-48. 10.1016/0042-6822(83)90531-7.

    CAS  PubMed  Google Scholar 

  50. 50.

    Lacal JC, Carrasco L: Relationship between membrane integrity and the inhibition of host translation in virus-infected mammalian cells. Comparative studies between encephalomyocarditis virus and poliovirus. Eur J Biochem. 1982, 127: 359-366. 10.1111/j.1432-1033.1982.tb06880.x.

    CAS  PubMed  Google Scholar 

  51. 51.

    Guinea R, Carrasco L: Phospholipid biosynthesis and poliovirus genome replication, two coupled phenomena. Embo J. 1990, 9: 2011-2016.

    PubMed Central  CAS  PubMed  Google Scholar 

  52. 52.

    Schlegel A, Giddings TH, Ladinsky MS, Kirkegaard K: Cellular origin and ultrastructure of membranes induced during poliovirus infection. J Virol. 1996, 70: 6576-6588.

    PubMed Central  CAS  PubMed  Google Scholar 

  53. 53.

    Bienz K, Egger D, Pfister T, Troxler M: Structural and functional characterization of the poliovirus replication complex. J Virol. 1992, 66: 2740-2747.

    PubMed Central  CAS  PubMed  Google Scholar 

  54. 54.

    Suhy DA, Giddings TH, Kirkegaard K: Remodeling the endoplasmic reticulum by poliovirus infection and by individual viral proteins: an autophagy-like origin for virus-induced vesicles. J Virol. 2000, 74: 8953-8965. 10.1128/JVI.74.19.8953-8965.2000.

    PubMed Central  CAS  PubMed  Google Scholar 

  55. 55.

    Bienz K, Egger D, Pfister T: Characteristics of the poliovirus replication complex. Arch Virol Suppl. 1994, 9: 147-157.

    CAS  PubMed  Google Scholar 

  56. 56.

    Aldabe R, Barco A, Carrasco L: Membrane permeabilization by poliovirus proteins 2B and 2BC. J Biol Chem. 1996, 271: 23134-23137. 10.1074/jbc.271.38.23134.

    CAS  PubMed  Google Scholar 

  57. 57.

    van Kuppeveld FJ, Hoenderop JG, Smeets RL, Willems PH, Dijkman HB, Galama JM, Melchers WJ: Coxsackievirus protein 2B modifies endoplasmic reticulum membrane and plasma membrane permeability and facilitates virus release. Embo J. 1997, 16: 3519-3532. 10.1093/emboj/16.12.3519.

    PubMed Central  CAS  PubMed  Google Scholar 

  58. 58.

    Doedens JR, Kirkegaard K: Inhibition of cellular protein secretion by poliovirus proteins 2B and 3A. Embo J. 1995, 14: 894-907.

    PubMed Central  CAS  PubMed  Google Scholar 

  59. 59.

    Barco A, Carrasco L: A human virus protein, poliovirus protein 2BC, induces membrane proliferation and blocks the exocytic pathway in the yeast Saccharomyces cerevisiae. Embo J. 1995, 14: 3349-3364.

    PubMed Central  CAS  PubMed  Google Scholar 

  60. 60.

    van Kuppeveld FJ, Galama JM, Zoll J, Hurk van den PJ, Melchers WJ: Coxsackie B3 virus protein 2B contains cationic amphipathic helix that is required for viral RNA replication. J Virol. 1996, 70: 3876-3886.

    PubMed Central  CAS  PubMed  Google Scholar 

  61. 61.

    Rust RC, Landmann L, Gosert R, Tang BL, Hong W, Hauri HP, Egger D, Bienz K: Cellular COPII proteins are involved in production of the vesicles that form the poliovirus replication complex. J Virol. 2001, 75: 9808-9818. 10.1128/JVI.75.20.9808-9818.2001.

    PubMed Central  CAS  PubMed  Google Scholar 

  62. 62.

    de Jong AS, Wessels E, Dijkman HB, Galama JM, Melchers WJ, Willems PH, van Kuppeveld FJ: Determinants for membrane association and permeabilization of the coxsackievirus 2B protein and the identification of the Golgi complex as the target organelle. J Biol Chem. 2003, 278: 1012-1021. 10.1074/jbc.M207745200.

    CAS  PubMed  Google Scholar 

  63. 63.

    de Jong AS, Schrama IW, Willems PH, Galama JM, Melchers WJ, van Kuppeveld FJ: Multimerization reactions of coxsackievirus proteins 2B, 2C and 2BC: a mammalian two-hybrid analysis. J Gen Virol. 2002, 83: 783-793.

    CAS  PubMed  Google Scholar 

  64. 64.

    de Jong AS, Melchers WJ, Glaudemans DH, Willems PH, van Kuppeveld FJ: Mutational analysis of different regions in the coxsackievirus 2B protein: requirements for homo-multimerization, membrane permeabilization, subcellular localization, and virus replication. J Biol Chem. 2004, 279: 19924-19935. 10.1074/jbc.M314094200.

    CAS  PubMed  Google Scholar 

  65. 65.

    Sandoval IV, Carrasco L: Poliovirus infection and expression of the poliovirus protein 2B provoke the disassembly of the Golgi complex, the organelle target for the antipoliovirus drug Ro-090179. J Virol. 1997, 71: 4679-4693.

    PubMed Central  CAS  PubMed  Google Scholar 

  66. 66.

    de Jong AS, Visch HJ, de Mattia F, van Dommelen MM, Swarts HG, Luyten T, Callewaert G, Melchers WJ, Willems PH, van Kuppeveld FJ: The coxsackievirus 2B protein increases efflux of ions from the endoplasmic reticulum and Golgi, thereby inhibiting protein trafficking through the Golgi. J Biol Chem. 2006, 281: 14144-14150. 10.1074/jbc.M511766200.

    CAS  PubMed  Google Scholar 

  67. 67.

    de Jong AS, de Mattia F, Van Dommelen MM, Lanke K, Melchers WJ, Willems PH, van Kuppeveld FJ: Functional analysis of picornavirus 2B proteins: effects on calcium homeostasis and intracellular protein trafficking. J Virol. 2008, 82: 3782-3790. 10.1128/JVI.02076-07.

    PubMed Central  CAS  PubMed  Google Scholar 

  68. 68.

    Campanella M, de Jong AS, Lanke KW, Melchers WJ, Willems PH, Pinton P, Rizzuto R, van Kuppeveld FJ: The coxsackievirus 2B protein suppresses apoptotic host cell responses by manipulating intracellular Ca2+ homeostasis. J Biol Chem. 2004, 279: 18440-18450. 10.1074/jbc.M309494200.

    CAS  PubMed  Google Scholar 

  69. 69.

    Paulmann D, Magulski T, Schwarz R, Heitmann L, Flehmig B, Vallbracht A, Dotzauer A: Hepatitis A virus protein 2B suppresses beta interferon (IFN) gene transcription by interfering with IFN regulatory factor 3 activation. J Gen Virol. 2008, 89: 1593-1604. 10.1099/vir.0.83521-0.

    CAS  PubMed  Google Scholar 

  70. 70.

    Doedens JR, Giddings TH, Kirkegaard K: Inhibition of endoplasmic reticulum-to-Golgi traffic by poliovirus protein 3A: genetic and ultrastructural analysis. J Virol. 1997, 71: 9054-9064.

    PubMed Central  CAS  PubMed  Google Scholar 

  71. 71.

    Belov GA, Fogg MH, Ehrenfeld E: Poliovirus proteins induce membrane association of GTPase ADP-ribosylation factor. J Virol. 2005, 79: 7207-7216. 10.1128/JVI.79.11.7207-7216.2005.

    PubMed Central  CAS  PubMed  Google Scholar 

  72. 72.

    Behnia R, Munro S: Organelle identity and the signposts for membrane traffic. Nature. 2005, 438: 597-604. 10.1038/nature04397.

    CAS  PubMed  Google Scholar 

  73. 73.

    Peyroche A, Antonny B, Robineau S, Acker J, Cherfils J, Jackson CL: Brefeldin A acts to stabilize an abortive ARF-GDP-Sec7 domain protein complex: involvement of specific residues of the Sec7 domain. Mol Cell. 1999, 3: 275-285. 10.1016/S1097-2765(00)80455-4.

    CAS  PubMed  Google Scholar 

  74. 74.

    Cuconati A, Molla A, Wimmer E: Brefeldin A inhibits cell-free, de novo synthesis of poliovirus. J Virol. 1998, 72: 6456-6464.

    PubMed Central  CAS  PubMed  Google Scholar 

  75. 75.

    Doedens J, Maynell LA, Klymkowsky MW, Kirkegaard K: Secretory pathway function, but not cytoskeletal integrity, is required in poliovirus infection. Arch Virol Suppl. 1994, 9: 159-172.

    CAS  PubMed  Google Scholar 

  76. 76.

    Maynell LA, Kirkegaard K, Klymkowsky MW: Inhibition of poliovirus RNA synthesis by brefeldin A. J Virol. 1992, 66: 1985-1994.

    PubMed Central  CAS  PubMed  Google Scholar 

  77. 77.

    Belov GA, Altan-Bonnet N, Kovtunovych G, Jackson CL, Lippincott-Schwartz J, Ehrenfeld E: Hijacking components of the cellular secretory pathway for replication of poliovirus RNA. J Virol. 2007, 81: 558-567. 10.1128/JVI.01820-06.

    PubMed Central  CAS  PubMed  Google Scholar 

  78. 78.

    Wessels E, Duijsings D, Lanke KH, van Dooren SH, Jackson CL, Melchers WJ, van Kuppeveld FJ: Effects of picornavirus 3A Proteins on Protein Transport and GBF1-dependent COP-I recruitment. J Virol. 2006, 80: 11852-11860. 10.1128/JVI.01225-06.

    PubMed Central  CAS  PubMed  Google Scholar 

  79. 79.

    Towner JS, Ho TV, Semler BL: Determinants of membrane association for poliovirus protein 3AB. J Biol Chem. 1996, 271: 26810-26818. 10.1074/jbc.271.43.26810.

    CAS  PubMed  Google Scholar 

  80. 80.

    Fujita K, Krishnakumar SS, Franco D, Paul AV, London E, Wimmer E: Membrane topography of the hydrophobic anchor sequence of poliovirus 3A and 3AB proteins and the functional effect of 3A/3AB membrane association upon RNA replication. Biochemistry. 2007, 46: 5185-5199. 10.1021/bi6024758.

    PubMed Central  CAS  PubMed  Google Scholar 

  81. 81.

    Hope DA, Diamond SE, Kirkegaard K: Genetic dissection of interaction between poliovirus 3D polymerase and viral protein 3AB. J Virol. 1997, 71: 9490-9498.

    PubMed Central  CAS  PubMed  Google Scholar 

  82. 82.

    Xiang W, Harris KS, Alexander L, Wimmer E: Interaction between the 5'-terminal cloverleaf and 3AB/3CDpro of poliovirus is essential for RNA replication. J Virol. 1995, 69: 3658-3667.

    PubMed Central  CAS  PubMed  Google Scholar 

  83. 83.

    Plotch SJ, Palant O: Poliovirus protein 3AB forms a complex with and stimulates the activity of the viral RNA polymerase, 3Dpol. J Virol. 1995, 69: 7169-7179.

    PubMed Central  CAS  PubMed  Google Scholar 

  84. 84.

    Richards OC, Spagnolo JF, Lyle JM, Vleck SE, Kuchta RD, Kirkegaard K: Intramolecular and intermolecular uridylylation by poliovirus RNA-dependent RNA polymerase. J Virol. 2006, 80: 7405-7415. 10.1128/JVI.02533-05.

    PubMed Central  CAS  PubMed  Google Scholar 

  85. 85.

    DeStefano JJ, Titilope O: Poliovirus protein 3AB displays nucleic acid chaperone and helix-destabilizing activities. J Virol. 2006, 80: 1662-1671. 10.1128/JVI.80.4.1662-1671.2006.

    PubMed Central  CAS  PubMed  Google Scholar 

  86. 86.

    Paul AV, van Boom JH, Filippov D, Wimmer E: Protein-primed RNA synthesis by purified poliovirus RNA polymerase. Nature. 1998, 393: 280-284. 10.1038/30529.

    CAS  PubMed  Google Scholar 

  87. 87.

    Takegami T, Kuhn RJ, Anderson CW, Wimmer E: Membrane-dependent uridylylation of the genome-linked protein VPg of poliovirus. Proc Natl Acad Sci USA. 1983, 80: 7447-7451. 10.1073/pnas.80.24.7447.

    PubMed Central  CAS  PubMed  Google Scholar 

  88. 88.

    Pettersson RF, Ambros V, Baltimore D: Identification of a protein linked to nascent poliovirus RNA and to the polyuridylic acid of negative-strand RNA. J Virol. 1978, 27: 357-365.

    PubMed Central  CAS  PubMed  Google Scholar 

  89. 89.

    Harris KS, Reddigari SR, Nicklin MJ, Hammerle T, Wimmer E: Purification and characterization of poliovirus polypeptide 3CD, a proteinase and a precursor for RNA polymerase. J Virol. 1992, 66: 7481-7489.

    PubMed Central  CAS  PubMed  Google Scholar 

  90. 90.

    Jore J, De Geus B, Jackson RJ, Pouwels PH, Enger-Valk BE: Poliovirus protein 3CD is the active protease for processing of the precursor protein P1 in vitro. J Gen Virol. 1988, 69 (Pt 7): 1627-1636. 10.1099/0022-1317-69-7-1627.

    CAS  PubMed  Google Scholar 

  91. 91.

    Harris KS, Xiang W, Alexander L, Lane WS, Paul AV, Wimmer E: Interaction of poliovirus polypeptide 3CDpro with the 5' and 3' termini of the poliovirus genome. Identification of viral and cellular cofactors needed for efficient binding. J Biol Chem. 1994, 269: 27004-27014.

    CAS  PubMed  Google Scholar 

  92. 92.

    Parsley TB, Towner JS, Blyn LB, Ehrenfeld E, Semler BL: Poly (rC) binding protein 2 forms a ternary complex with the 5'-terminal sequences of poliovirus RNA and the viral 3CD proteinase. Rna. 1997, 3: 1124-1134.

    PubMed Central  CAS  PubMed  Google Scholar 

  93. 93.

    Gamarnik AV, Andino R: Two functional complexes formed by KH domain containing proteins with the 5' noncoding region of poliovirus RNA. Rna. 1997, 3: 882-892.

    PubMed Central  CAS  PubMed  Google Scholar 

  94. 94.

    Blyn LB, Swiderek KM, Richards O, Stahl DC, Semler BL, Ehrenfeld E: Poly(rC) binding protein 2 binds to stem-loop IV of the poliovirus RNA 5' noncoding region: identification by automated liquid chromatography-tandem mass spectrometry. Proc Natl Acad Sci USA. 1996, 93: 11115-11120. 10.1073/pnas.93.20.11115.

    PubMed Central  CAS  PubMed  Google Scholar 

  95. 95.

    Walter BL, Parsley TB, Ehrenfeld E, Semler BL: Distinct poly(rC) binding protein KH domain determinants for poliovirus translation initiation and viral RNA replication. J Virol. 2002, 76: 12008-12022. 10.1128/JVI.76.23.12008-12022.2002.

    PubMed Central  CAS  PubMed  Google Scholar 

  96. 96.

    Lin JY, Li ML, Huang PN, Chien KY, Horng JT, Shih SR: Heterogeneous nuclear ribonuclear protein K interacts with the enterovirus 71 5' untranslated region and participates in virus replication. J Gen Virol. 2008, 89: 2540-2549. 10.1099/vir.0.2008/003673-0.

    CAS  PubMed  Google Scholar 

  97. 97.

    Brunner JE, Nguyen JH, Roehl HH, Ho TV, Swiderek KM, Semler BL: Functional interaction of heterogeneous nuclear ribonucleoprotein C with poliovirus RNA synthesis initiation complexes. J Virol. 2005, 79: 3254-3266. 10.1128/JVI.79.6.3254-3266.2005.

    PubMed Central  CAS  PubMed  Google Scholar 

  98. 98.

    Gamarnik AV, Andino R: Interactions of viral protein 3CD and poly(rC) binding protein with the 5' untranslated region of the poliovirus genome. J Virol. 2000, 74: 2219-2226. 10.1128/JVI.74.5.2219-2226.2000.

    PubMed Central  CAS  PubMed  Google Scholar 

  99. 99.

    Rieder E, Paul AV, Kim DW, van Boom JH, Wimmer E: Genetic and biochemical studies of poliovirus cis-acting replication element cre in relation to VPg uridylylation. J Virol. 2000, 74: 10371-10380. 10.1128/JVI.74.22.10371-10380.2000.

    PubMed Central  CAS  PubMed  Google Scholar 

  100. 100.

    Paul AV, Rieder E, Kim DW, van Boom JH, Wimmer E: Identification of an RNA hairpin in poliovirus RNA that serves as the primary template in the in vitro uridylylation of VPg. J Virol. 2000, 74: 10359-10370. 10.1128/JVI.74.22.10359-10370.2000.

    PubMed Central  CAS  PubMed  Google Scholar 

  101. 101.

    Van Dyke TA, Flanegan JB: Identification of poliovirus polypeptide P63 as a soluble RNA-dependent RNA polymerase. J Virol. 1980, 35: 732-740.

    PubMed Central  CAS  PubMed  Google Scholar 

  102. 102.

    Paul AV, Peters J, Mugavero J, Yin J, van Boom JH, Wimmer E: Biochemical and genetic studies of the VPg uridylylation reaction catalyzed by the RNA polymerase of poliovirus. J Virol. 2003, 77: 891-904. 10.1128/JVI.77.2.891-904.2003.

    PubMed Central  CAS  PubMed  Google Scholar 

  103. 103.

    Hobson SD, Rosenblum ES, Richards OC, Richmond K, Kirkegaard K, Schultz SC: Oligomeric structures of poliovirus polymerase are important for function. Embo J. 2001, 20: 1153-1163. 10.1093/emboj/20.5.1153.

    PubMed Central  CAS  PubMed  Google Scholar 

  104. 104.

    Pata JD, Schultz SC, Kirkegaard K: Functional oligomerization of poliovirus RNA-dependent RNA polymerase. Rna. 1995, 1: 466-477.

    PubMed Central  CAS  PubMed  Google Scholar 

  105. 105.

    McBride AE, Schlegel A, Kirkegaard K: Human protein Sam68 relocalization and interaction with poliovirus RNA polymerase in infected cells. Proc Natl Acad Sci USA. 1996, 93: 2296-2301. 10.1073/pnas.93.6.2296.

    PubMed Central  CAS  PubMed  Google Scholar 

  106. 106.

    Herold J, Andino R: Poliovirus RNA replication requires genome circularization through a protein-protein bridge. Mol Cell. 2001, 7: 581-591. 10.1016/S1097-2765(01)00205-2.

    CAS  PubMed  Google Scholar 

  107. 107.

    Barton DJ, O'Donnell BJ, Flanegan JB: 5' cloverleaf in poliovirus RNA is a cis-acting replication element required for negative-strand synthesis. Embo J. 2001, 20: 1439-1448. 10.1093/emboj/20.6.1439.

    PubMed Central  CAS  PubMed  Google Scholar 

  108. 108.

    Mellits KH, Meredith JM, Rohll JB, Evans DJ, Almond JW: Binding of a cellular factor to the 3' untranslated region of the RNA genomes of entero- and rhinoviruses plays a role in virus replication. J Gen Virol. 1998, 79 (Pt 7): 1715-1723.

    CAS  PubMed  Google Scholar 

  109. 109.

    Todd S, Nguyen JH, Semler BL: RNA-protein interactions directed by the 3' end of human rhinovirus genomic RNA. J Virol. 1995, 69: 3605-3614.

    PubMed Central  CAS  PubMed  Google Scholar 

  110. 110.

    Waggoner S, Sarnow P: Viral ribonucleoprotein complex formation and nucleolar-cytoplasmic relocalization of nucleolin in poliovirus-infected cells. J Virol. 1998, 72: 6699-6709.

    PubMed Central  CAS  PubMed  Google Scholar 

  111. 111.

    Banerjee R, Echeverri A, Dasgupta A: Poliovirus-encoded 2C polypeptide specifically binds to the 3'-terminal sequences of viral negative-strand RNA. J Virol. 1997, 71: 9570-9578.

    PubMed Central  CAS  PubMed  Google Scholar 

  112. 112.

    Cheung P, Lim T, Yuan J, Zhang M, Chau D, McManus B, Yang D: Specific interaction of HeLa cell proteins with coxsackievirus B3 3'UTR: La autoantigen binds the 3' and 5'UTR independently of the poly(A) tail. Cell Microbiol. 2007, 9: 1705-1715. 10.1111/j.1462-5822.2007.00904.x.

    CAS  PubMed  Google Scholar 

  113. 113.

    Gerber K, Wimmer E, Paul AV: Biochemical and genetic studies of the initiation of human rhinovirus 2 RNA replication: identification of a cis-replicating element in the coding sequence of 2A(pro). J Virol. 2001, 75: 10979-10990. 10.1128/JVI.75.22.10979-10990.2001.

    PubMed Central  CAS  PubMed  Google Scholar 

  114. 114.

    Goodfellow I, Chaudhry Y, Richardson A, Meredith J, Almond JW, Barclay W, Evans DJ: Identification of a cis-acting replication element within the poliovirus coding region. J Virol. 2000, 74: 4590-4600. 10.1128/JVI.74.10.4590-4600.2000.

    PubMed Central  CAS  PubMed  Google Scholar 

  115. 115.

    Lobert PE, Escriou N, Ruelle J, Michiels T: A coding RNA sequence acts as a replication signal in cardioviruses. Proc Natl Acad Sci USA. 1999, 96: 11560-11565. 10.1073/pnas.96.20.11560.

    PubMed Central  CAS  PubMed  Google Scholar 

  116. 116.

    Mason PW, Bezborodova SV, Henry TM: Identification and characterization of a cis-acting replication element (cre) adjacent to the internal ribosome entry site of foot-and-mouth disease virus. J Virol. 2002, 76: 9686-9694. 10.1128/JVI.76.19.9686-9694.2002.

    PubMed Central  CAS  PubMed  Google Scholar 

  117. 117.

    McKnight KL, Lemon SM: The rhinovirus type 14 genome contains an internally located RNA structure that is required for viral replication. Rna. 1998, 4: 1569-1584. 10.1017/S1355838298981006.

    PubMed Central  CAS  PubMed  Google Scholar 

  118. 118.

    Yang Y, Yi M, Evans DJ, Simmonds P, Lemon SM: Identification of a conserved RNA replication element (cre) within the 3Dpol-coding sequence of hepatoviruses. J Virol. 2008, 82: 10118-10128. 10.1128/JVI.00787-08.

    PubMed Central  CAS  PubMed  Google Scholar 

  119. 119.

    Barton DJ, Morasco BJ, Flanegan JB: Translating ribosomes inhibit poliovirus negative-strand RNA synthesis. J Virol. 1999, 73: 10104-10112.

    PubMed Central  CAS  PubMed  Google Scholar 

  120. 120.

    Rohll JB, Percy N, Ley R, Evans DJ, Almond JW, Barclay WS: The 5'-untranslated regions of picornavirus RNAs contain independent functional domains essential for RNA replication and translation. J Virol. 1994, 68: 4384-4391.

    PubMed Central  CAS  PubMed  Google Scholar 

  121. 121.

    Gamarnik AV, Andino R: Switch from translation to RNA replication in a positive-stranded RNA virus. Genes Dev. 1998, 12: 2293-2304. 10.1101/gad.12.15.2293.

    PubMed Central  CAS  PubMed  Google Scholar 

  122. 122.

    Perera R, Daijogo S, Walter BL, Nguyen JH, Semler BL: Cellular protein modification by poliovirus: the two faces of poly(rC)-binding protein. J Virol. 2007, 81: 8919-8932. 10.1128/JVI.01013-07.

    PubMed Central  CAS  PubMed  Google Scholar 

  123. 123.

    Pisarev AV, Chard LS, Kaku Y, Johns HL, Shatsky IN, Belsham GJ: Functional and structural similarities between the internal ribosome entry sites of hepatitis C virus and porcine teschovirus, a picornavirus. J Virol. 2004, 78: 4487-4497. 10.1128/JVI.78.9.4487-4497.2004.

    PubMed Central  CAS  PubMed  Google Scholar 

  124. 124.

    Pilipenko EV, Pestova TV, Kolupaeva VG, Khitrina EV, Poperechnaya AN, Agol VI, Hellen CU: A cell cycle-dependent protein serves as a template-specific translation initiation factor. Genes Dev. 2000, 14: 2028-2045.

    PubMed Central  CAS  PubMed  Google Scholar 

  125. 125.

    Hellen CU, Sarnow P: Internal ribosome entry sites in eukaryotic mRNA molecules. Genes Dev. 2001, 15: 1593-1612. 10.1101/gad.891101.

    CAS  PubMed  Google Scholar 

  126. 126.

    Michael WM, Siomi H, Choi M, Pinol-Roma S, Nakielny S, Liu Q, Dreyfuss G: Signal sequences that target nuclear import and nuclear export of pre-mRNA-binding proteins. Cold Spring Harb Symp Quant Biol. 1995, 60: 663-668.

    CAS  PubMed  Google Scholar 

  127. 127.

    Gil A, Sharp PA, Jamison SF, Garcia-Blanco MA: Characterization of cDNAs encoding the polypyrimidine tract-binding protein. Genes Dev. 1991, 5: 1224-1236. 10.1101/gad.5.7.1224.

    CAS  PubMed  Google Scholar 

  128. 128.

    Singh R, Valcarcel J, Green MR: Distinct binding specificities and functions of higher eukaryotic polypyrimidine tract-binding proteins. Science. 1995, 268: 1173-1176. 10.1126/science.7761834.

    CAS  PubMed  Google Scholar 

  129. 129.

    Andino R, Boddeker N, Silvera D, Gamarnik AV: Intracellular determinants of picornavirus replication. Trends Microbiol. 1999, 7: 76-82. 10.1016/S0966-842X(98)01446-2.

    CAS  PubMed  Google Scholar 

  130. 130.

    Belsham GJ, Sonenberg N: Picornavirus RNA translation: roles for cellular proteins. Trends Microbiol. 2000, 8: 330-335. 10.1016/S0966-842X(00)01788-1.

    CAS  PubMed  Google Scholar 

  131. 131.

    Gutierrez-Escolano L, del Angel RM: Nuclear proteins bind to poliovirus 5' untranslated region. Arch Med Res. 1996, 27: 413-419.

    CAS  PubMed  Google Scholar 

  132. 132.

    Hellen CU, Witherell GW, Schmid M, Shin SH, Pestova TV, Gil A, Wimmer E: A cytoplasmic 57-kDa protein that is required for translation of picornavirus RNA by internal ribosomal entry is identical to the nuclear pyrimidine tract-binding protein. Proc Natl Acad Sci USA. 1993, 90: 7642-7646. 10.1073/pnas.90.16.7642.

    PubMed Central  CAS  PubMed  Google Scholar 

  133. 133.

    Niepmann M, Petersen A, Meyer K, Beck E: Functional involvement of polypyrimidine tract-binding protein in translation initiation complexes with the internal ribosome entry site of foot-and-mouth disease virus. J Virol. 1997, 71: 8330-8339.

    PubMed Central  CAS  PubMed  Google Scholar 

  134. 134.

    Kaminski A, Hunt SL, Patton JG, Jackson RJ: Direct evidence that polypyrimidine tract binding protein (PTB) is essential for internal initiation of translation of encephalomyocarditis virus RNA. Rna. 1995, 1: 924-938.

    PubMed Central  CAS  PubMed  Google Scholar 

  135. 135.

    Pilipenko EV, Viktorova EG, Guest ST, Agol VI, Roos RP: Cell-specific proteins regulate viral RNA translation and virus-induced disease. Embo J. 2001, 20: 6899-6908. 10.1093/emboj/20.23.6899.

    PubMed Central  CAS  PubMed  Google Scholar 

  136. 136.

    Chang KH, Brown EA, Lemon SM: Cell type-specific proteins which interact with the 5' nontranslated region of hepatitis A virus RNA. J Virol. 1993, 67: 6716-6725.

    PubMed Central  CAS  PubMed  Google Scholar 

  137. 137.

    Yi M, Schultz DE, Lemon SM: Functional significance of the interaction of hepatitis A virus RNA with glyceraldehyde 3-phosphate dehydrogenase (GAPDH): opposing effects of GAPDH and polypyrimidine tract binding protein on internal ribosome entry site function. J Virol. 2000, 74: 6459-6468. 10.1128/JVI.74.14.6459-6468.2000.

    PubMed Central  CAS  PubMed  Google Scholar 

  138. 138.

    Kaminski A, Jackson RJ: The polypyrimidine tract binding protein (PTB) requirement for internal initiation of translation of cardiovirus RNAs is conditional rather than absolute. Rna. 1998, 4: 626-638. 10.1017/S1355838298971898.

    PubMed Central  CAS  PubMed  Google Scholar 

  139. 139.

    Hunt SL, Hsuan JJ, Totty N, Jackson RJ: unr, a cellular cytoplasmic RNA-binding protein with five cold-shock domains, is required for internal initiation of translation of human rhinovirus RNA. Genes Dev. 1999, 13: 437-448. 10.1101/gad.13.4.437.

    PubMed Central  CAS  PubMed  Google Scholar 

  140. 140.

    Hunt SL, Jackson RJ: Polypyrimidine-tract binding protein (PTB) is necessary, but not sufficient, for efficient internal initiation of translation of human rhinovirus-2 RNA. Rna. 1999, 5: 344-359. 10.1017/S1355838299981414.

    PubMed Central  CAS  PubMed  Google Scholar 

  141. 141.

    Gosert R, Chang KH, Rijnbrand R, Yi M, Sangar DV, Lemon SM: Transient expression of cellular polypyrimidine-tract binding protein stimulates cap-independent translation directed by both picornaviral and flaviviral internal ribosome entry sites In vivo. Mol Cell Biol. 2000, 20: 1583-1595. 10.1128/MCB.20.5.1583-1595.2000.

    PubMed Central  CAS  PubMed  Google Scholar 

  142. 142.

    Back SH, Kim YK, Kim WJ, Cho S, Oh HR, Kim JE, Jang SK: Translation of polioviral mRNA is inhibited by cleavage of polypyrimidine tract-binding proteins executed by polioviral 3C(pro). J Virol. 2002, 76: 2529-2542. 10.1128/jvi.76.5.2529-2542.2002.

    PubMed Central  CAS  PubMed  Google Scholar 

  143. 143.

    Guest S, Pilipenko E, Sharma K, Chumakov K, Roos RP: Molecular mechanisms of attenuation of the Sabin strain of poliovirus type 3. J Virol. 2004, 78: 11097-11107. 10.1128/JVI.78.20.11097-11107.2004.

    PubMed Central  CAS  PubMed  Google Scholar 

  144. 144.

    Song Y, Tzima E, Ochs K, Bassili G, Trusheim H, Linder M, Preissner KT, Niepmann M: Evidence for an RNA chaperone function of polypyrimidine tract-binding protein in picornavirus translation. Rna. 2005, 11: 1809-1824. 10.1261/rna.7430405.

    PubMed Central  CAS  PubMed  Google Scholar 

  145. 145.

    Kolupaeva VG, Hellen CU, Shatsky IN: Structural analysis of the interaction of the pyrimidine tract-binding protein with the internal ribosomal entry site of encephalomyocarditis virus and foot-and-mouth disease virus RNAs. Rna. 1996, 2: 1199-1212.

    PubMed Central  CAS  PubMed  Google Scholar 

  146. 146.

    Meerovitch K, Svitkin YV, Lee HS, Lejbkowicz F, Kenan DJ, Chan EK, Agol VI, Keene JD, Sonenberg N: La autoantigen enhances and corrects aberrant translation of poliovirus RNA in reticulocyte lysate. J Virol. 1993, 67: 3798-3807.

    PubMed Central  CAS  PubMed  Google Scholar 

  147. 147.

    Shiroki K, Isoyama T, Kuge S, Ishii T, Ohmi S, Hata S, Suzuki K, Takasaki Y, Nomoto A: Intracellular redistribution of truncated La protein produced by poliovirus 3Cpro-mediated cleavage. J Virol. 1999, 73: 2193-2200.

    PubMed Central  CAS  PubMed  Google Scholar 

  148. 148.

    Costa-Mattioli M, Svitkin Y, Sonenberg N: La autoantigen is necessary for optimal function of the poliovirus and hepatitis C virus internal ribosome entry site in vivo and in vitro. Mol Cell Biol. 2004, 24: 6861-6870. 10.1128/MCB.24.15.6861-6870.2004.

    PubMed Central  CAS  PubMed  Google Scholar 

  149. 149.

    Cheung P, Zhang M, Yuan J, Chau D, Yanagawa B, McManus B, Yang D: Specific interactions of HeLa cell proteins with Coxsackievirus B3 RNA: La autoantigen binds differentially to multiple sites within the 5' untranslated region. Virus Res. 2002, 90: 23-36. 10.1016/S0168-1702(02)00138-7.

    CAS  PubMed  Google Scholar 

  150. 150.

    Ray PS, Das S: La autoantigen is required for the internal ribosome entry site-mediated translation of Coxsackievirus B3 RNA. Nucleic Acids Res. 2002, 30: 4500-4508. 10.1093/nar/gkf583.

    PubMed Central  CAS  PubMed  Google Scholar 

  151. 151.

    Cordes S, Kusov Y, Heise T, Gauss-Muller V: La autoantigen suppresses IRES-dependent translation of the hepatitis A virus. Biochem Biophys Res Commun. 2008, 368: 1014-1019. 10.1016/j.bbrc.2008.01.163.

    CAS  PubMed  Google Scholar 

  152. 152.

    Blyn LB, Towner JS, Semler BL, Ehrenfeld E: Requirement of poly(rC) binding protein 2 for translation of poliovirus RNA. J Virol. 1997, 71: 6243-6246.

    PubMed Central  CAS  PubMed  Google Scholar 

  153. 153.

    Choi K, Kim JH, Li X, Paek KY, Ha SH, Ryu SH, Wimmer E, Jang SK: Identification of cellular proteins enhancing activities of internal ribosomal entry sites by competition with oligodeoxynucleotides. Nucleic Acids Res. 2004, 32: 1308-1317. 10.1093/nar/gkh300.

    PubMed Central  CAS  PubMed  Google Scholar 

  154. 154.

    Graff J, Cha J, Blyn LB, Ehrenfeld E: Interaction of poly(rC) binding protein 2 with the 5' noncoding region of hepatitis A virus RNA and its effects on translation. J Virol. 1998, 72: 9668-9675.

    PubMed Central  CAS  PubMed  Google Scholar 

  155. 155.

    Bedard KM, Daijogo S, Semler BL: A nucleo-cytoplasmic SR protein functions in viral IRES-mediated translation initiation. Embo J. 2007, 26: 459-467. 10.1038/sj.emboj.7601494.

    PubMed Central  CAS  PubMed  Google Scholar 

  156. 156.

    Walter BL, Nguyen JH, Ehrenfeld E, Semler BL: Differential utilization of poly(rC) binding protein 2 in translation directed by picornavirus IRES elements. Rna. 1999, 5: 1570-1585. 10.1017/S1355838299991483.

    PubMed Central  CAS  PubMed  Google Scholar 

  157. 157.

    Boussadia O, Niepmann M, Creancier L, Prats AC, Dautry F, Jacquemin-Sablon H: Unr is required in vivo for efficient initiation of translation from the internal ribosome entry sites of both rhinovirus and poliovirus. J Virol. 2003, 77: 3353-3359. 10.1128/JVI.77.6.3353-3359.2003.

    PubMed Central  CAS  PubMed  Google Scholar 

  158. 158.

    Cammas A, Pileur F, Bonnal S, Lewis SM, Leveque N, Holcik M, Vagner S: Cytoplasmic relocalization of heterogeneous nuclear ribonucleoprotein A1 controls translation initiation of specific mRNAs. Mol Biol Cell. 2007, 18: 5048-5059. 10.1091/mbc.E07-06-0603.

    PubMed Central  CAS  PubMed  Google Scholar 

  159. 159.

    Lin JY, Shih SR, Pan M, Li C, Lue CF, Stollar V, Li ML: hnRNP A1 Interacts with the 5'UTRs of Enterovirus 71 and Sindbis virus RNA and is Required for Viral Replication. J Virol. 2009

    Google Scholar 

  160. 160.

    Bugler B, Bourbon H, Lapeyre B, Wallace MO, Chang JH, Amalric F, Olson MO: RNA binding fragments from nucleolin contain the ribonucleoprotein consensus sequence. J Biol Chem. 1987, 262: 10922-10925.

    CAS  PubMed  Google Scholar 

  161. 161.

    Ginisty H, Sicard H, Roger B, Bouvet P: Structure and functions of nucleolin. J Cell Sci. 1999, 112 (Pt 6): 761-772.

    CAS  PubMed  Google Scholar 

  162. 162.

    Izumi RE, Valdez B, Banerjee R, Srivastava M, Dasgupta A: Nucleolin stimulates viral internal ribosome entry site-mediated translation. Virus Res. 2001, 76: 17-29. 10.1016/S0168-1702(01)00240-4.

    CAS  PubMed  Google Scholar 

  163. 163.

    Merrill MK, Dobrikova EY, Gromeier M: Cell-type-specific repression of internal ribosome entry site activity by double-stranded RNA-binding protein 76. J Virol. 2006, 80: 3147-3156. 10.1128/JVI.80.7.3147-3156.2006.

    PubMed Central  CAS  PubMed  Google Scholar 

  164. 164.

    Merrill MK, Gromeier M: The double-stranded RNA binding protein 76:NF45 heterodimer inhibits translation initiation at the rhinovirus type 2 internal ribosome entry site. J Virol. 2006, 80: 6936-6942. 10.1128/JVI.00243-06.

    PubMed Central  CAS  PubMed  Google Scholar 

  165. 165.

    Min H, Turck CW, Nikolic JM, Black DL: A new regulatory protein, KSRP, mediates exon inclusion through an intronic splicing enhancer. Genes Dev. 1997, 11: 1023-1036. 10.1101/gad.11.8.1023.

    CAS  PubMed  Google Scholar 

  166. 166.

    Chen CY, Gherzi R, Ong SE, Chan EL, Raijmakers R, Pruijn GJ, Stoecklin G, Moroni C, Mann M, Karin M: AU binding proteins recruit the exosome to degrade ARE-containing mRNAs. Cell. 2001, 107: 451-464. 10.1016/S0092-8674(01)00578-5.

    CAS  PubMed  Google Scholar 

  167. 167.

    Gherzi R, Lee KY, Briata P, Wegmuller D, Moroni C, Karin M, Chen CY: A KH domain RNA binding protein, KSRP, promotes ARE-directed mRNA turnover by recruiting the degradation machinery. Mol Cell. 2004, 14: 571-583. 10.1016/j.molcel.2004.05.002.

    CAS  PubMed  Google Scholar 

  168. 168.

    Lin JY, Li ML, Shih SR: Far upstream element binding protein 2 interacts with enterovirus 71 internal ribosomal entry site and negatively regulates viral translation. Nucleic Acids Res. 2009, 37: 47-59. 10.1093/nar/gkn901.

    PubMed Central  CAS  PubMed  Google Scholar 

  169. 169.

    Huber M, Watson KA, Selinka HC, Carthy CM, Klingel K, McManus BM, Kandolf R: Cleavage of RasGAP and phosphorylation of mitogen-activated protein kinase in the course of coxsackievirus B3 replication. J Virol. 1999, 73: 3587-3594.

    PubMed Central  CAS  PubMed  Google Scholar 

  170. 170.

    Zhang B, Seitz S, Kusov Y, Zell R, Gauss-Muller V: RNA interaction and cleavage of poly(C)-binding protein 2 by hepatitis A virus protease. Biochem Biophys Res Commun. 2007, 364: 725-730. 10.1016/j.bbrc.2007.09.133.

    CAS  PubMed  Google Scholar 

  171. 171.

    Kim YK, Jang SK: La protein is required for efficient translation driven by encephalomyocarditis virus internal ribosomal entry site. J Gen Virol. 1999, 80 (Pt 12): 3159-3166.

    CAS  PubMed  Google Scholar 

  172. 172.

    Schultz DE, Hardin CC, Lemon SM: Specific interaction of glyceraldehyde 3-phosphate dehydrogenase with the 5'-nontranslated RNA of hepatitis A virus. J Biol Chem. 1996, 271: 14134-14142. 10.1074/jbc.271.24.14134.

    CAS  PubMed  Google Scholar 

  173. 173.

    Svitkin YV, Imataka H, Khaleghpour K, Kahvejian A, Liebig HD, Sonenberg N: Poly(A)-binding protein interaction with elF4G stimulates picornavirus IRES-dependent translation. Rna. 2001, 7: 1743-1752. 10.1017/S135583820100108X.

    PubMed Central  CAS  PubMed  Google Scholar 

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The authors would like to thank the National Science Council of the Republic of China, Taiwan, for financially supporting this research under Contract No. NSC97-2320-B-182-007-MY3. Ted Knoy is appreciated for his editorial assistance.

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Correspondence to Shin-Ru Shih.

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The authors declare that they have no competing interests.

Authors' contributions

JYL: Contribution of the part of the induction of background, host factors and viral proteins involved in IRES-mediated translation and conclusion. SCC: Contribution of the part of host factors and capsid proteins that are involved in receptor binding. TCC: Contribution of the part of viral and host proteins involved in RNA replication. KFW: Contribution of the part of viral proteolytic activities influence cellular functions and viral and host proteins involved in RNA replication (2B/2BC). LLC: Contribution of the part of switch from translation to RNA replication. SRS: Contribution of a deep revision of the full text. All authors have read and approved the final manuscript.

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Lin, JY., Chen, TC., Weng, KF. et al. Viral and host proteins involved in picornavirus life cycle. J Biomed Sci 16, 103 (2009).

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  • Internal Ribosome Entry Site
  • Internal Ribosome Entry Site Element
  • Internal Ribosome Entry Site Activity
  • Viral Translation
  • EMCV Internal Ribosome Entry Site