Medicine

Regulation of nucleosome dynamics by histone modifications

Regulation of nucleosome dynamics by histone modifications

Regulation of nucleosome dynamics by histone modifications

Abstract

Eukaryotic genomes are tightly wound around octamers of core histone proteins to form nucleosomes, the basic unit of chromatin. Nucleosomes must be densely packed to achieve the 10,000–20,000-fold compaction1 necessary to fit a genome into the small volume of the nucleus but must also allow proteins involved in transcription, replication and repair to access DNA. The properties of nucleosomes can be altered in several ways, including the replacement of canonical core histones with specialized variants2, repositioning or eviction of histones from DNA by ATP-dependent chromatin remodeling enzymes3 and, the topic of this Review, covalent modification of histones. Histone modifications have been of great interest ever since the discovery that histones which are associated with highly transcribed genes are hyperacetylated4. In the nearly 50 years since that seminal discovery, well over 100 distinct histone modifications have been described, with more being discovered at a rapid pace. These range from the well known, such as lysine methylation, lysine acetylation and serine/threonine phosphorylation, to more exotic modifications such as crotonylation5,6

 

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