RNAi depletion of Mybbp1a alters epigenetic status of rDNA promoters. Mybbp1a regulates the association of RNA Pol I machinery and histone marks with rDNA promoter. Control (−) and knockdown (+) cell lines were subjected to ChIP for analyzing promoter binding of various Pol I components and epigenetic marks: UBF (A), RPA194 (B), H4ac, H3K9Ac, H3K9me3 and H4K20me3 (C). ChIP was carried out with control (IgG) or the specific antibodies, as denoted. Quantitative determination of the bound DNA, carried out with real-time PCR, is depicted by the bar graphs. Data presented are normalized to IgG values, with the ratio for each control group set to 1 (*p < 0.05; **p < 0.01).