Histone 2A and Histone 2B are two of the four core histones (which also include H3 and H4) fundamental in compacting eukaryotic DNA into the nucleosome. Within this nucleosome core, H2A and H2B form a dimer. Similar to the other core histone, H2A and H2B have globular domains and a flexible N-terminal domain; the “histone tail” which can undergo modifications such as acetylation, methylation, phosphorylation and ubiquitination.
These histone modifications can alter the positioning of the nucleosome, allowing DNA to be either accessible or inaccessible to the transcription machinery. These histone modifications can occur in different complex combinations; making up what is known as the “histone code”. Alterations in the histone modification patterns, can result in cancers, autoimmune diseases and cardiovascular and neurodegenerative disorders.