Histone Acetylation/Deacetylation and Regulation of Gene Expression

In eukaryotic cells, covalent modifications of the core histones in nucleosomes play a central role in regulation of gene expression. Several histone modifications have been identified including methylation, acetylation, phosphorylation and ubiquityination. Among them histone acetylation is of critical importance. The level of histone acetylation depends on the activity of two families of enzymes, histone acetyltransferases(HATs) and histone deacetylases(HDACs). Histone acetylation/deacetylation can not only alter the charge and the hydrophobicity of the histones, but also modulate the chromatin structure co operating with some other factors. This could be one of the potential mechanisms of gene regulation by histone acetylation/deacetylation. Recent advances suggest that the histones acetylation states might set a signal to serve as “histone code” that are recognized by other molecules linked to transcriptional activation or inactivation.