Mechanisms of Histone Modifications
Abstract The genome size is, on average, significantly larger in eukaryotes than in prokaryotes. This, on one hand contributed to the acquisition of a number of advantages. On the other hand, it increased the complexity of regulation of the activity, maintenance, and inheritance of the genomic material. To deal with this complexity, eukaryotic organisms acquired new proteins, called histones that not only allow packaging and protecting the DNA into a higher-order structure called chromatin, but can also regulate the accessibility to and the activity of different parts of the genome. This regulatory function is directed by multiple chemical modifications that can take place on the histones. Here, we introduce the most common histone modifications, the machineries that deposit and remove them, their distribution in the genome, and their role in key cellular processes, with a focus on transcriptional regulation and DNA repair.