21. The core of the histones H2A and H2B can also be modified. 22. Often, DNA methylation and histone deacetylation work together in gene silencing. 23. Also, activation or localization of two histone acetyltransferases can be oncogenic. 24. The reverse reaction of the acetylation is catalyzed by histone deacetylase 6. 25. Deacetylation of histones stabilizes tightly coiled nucleosomes, inhibiting RNA polymerase access. 26. Histone acetylation plays an important role in the regulation of gene expression.27. Transcription is also repressed by histone deacetylase-independent means. 28. Histone H2B is a lightweight structural protein made of 126 amino acids.29. Histone H2B s amino acid sequence is highly evolutionarily conserved.30. This can be done by modifying histones at certain sites by methylation.
