Histone H3 is one of four histone proteins that assemble into an octamer to form the nucleosome core and serve to spool and compact DNA into chromatin. Histones are subject to a complex set of post-translational modifications (acetylation, methylation, phosphorylation, ubiquitination, sumoylation, citrullination, and ADP ribosylation) that are important to the regulation of gene transcription, DNA replication, and DNA repair.
