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. Author manuscript; available in PMC: 2018 May 23.
Published in final edited form as: Cancer Biol Ther. 2010 Nov 15;10(10):961–978. doi: 10.4161/cbt.10.10.13923

Figure 3.

Figure 3

Epigenetic regulation by tumor virus encoded oncoproteins. Schematic showing epigenetic control of gene transcription by alterations in DNA methylation status and chromatin modifications by tumor virus encoded oncoproteins (red). Transcriptionally active DNA represents an open chromatin structure with widely spaced nucleosomes, associated with unmethylated CpG residues and specific post translational histone modifications, including increased levels of acetylation as well as other enzymes and co-factors. On the other hand, transcriptionally repressive conformation of DNA is characterized by methylated CpG islands, compacted nucleosomes, with deacetylated histones, and further post translational modifications, including methylation of specific histone H3 lysine residues. This repressive conformation renders the DNA inaccessible to the transcriptional machinery. MBPs, methyl-CpG binding proteins; HDACs, histone deacetylases; DNMTs, DNA methyltransferases; HATs, histone acetyl transferase.