Fig. 1

A simplified model for eukaryotic DNA replication forks. Unlike the situation in prokaryotes, eukaryotic DNA replication is carried out in the context of chromatin. Replication is initiated at multiple distinct replication origins along the chromosome. Unwinding of the double-stranded DNA at origins allows for assembly of a specialized structure called the replication fork (resembling a two-tined fork), where a large group of replication proteins (replication machinery) are dynamically coordinated to duplicate the genome. Importantly, there is a crucial interplay between the replication machinery and chromatin dynamics (including histone eviction and recycling at the fork, specific post-transcriptional modifications, and exchange of canonical histones with histone variants via histone chaperones). When replication forks encounter obstacles that block replicative DNA polymerases and induce fork stalling (replication stress), chromatin structural components may contribute to repair/checkpoint machineries that rescue cells from replication stress