Mybbp1a is important for maintaining rDNA promoter methylation. (A) & (B) The rDNA promoter was amplified from undigested (U, uncut), and HpaII- (H) or MspI-digested (M) genomic DNA from control (ctrl) or Mybbp1a (si-Mybbp1a) knockdown HeLa cells, and resolved on agarose gel (A). GAPDH promoter and chromosome 19 were amplified to control for complete restriction enzyme digestion and input DNA normalization, respectively. Quantitative analysis of the results in (A) was done using real-time PCR (B). (C) Quantitative DNA methylation analyses were done as in (B) with genomic DNA from HeLa cells transfected with control vector (−) or Myc-Mybbp1a-encoding construct (+). (For statistical analyses shown in this figure: *p < 0.05).