MacroH2A1 Background Information
Eukaryotic histones are water soluble, basic nuclear proteins that form hetero-octameric nucleosome particles by wrapping 146 base pairs of DNA in a left-handed super-helical turn sequentially to form chromosomal fiber. Two molecules of each of the four core histones (H2A, H2B, H3, and H4) form the octamer. The octamer consists of two H2A-H2B dimers and two H3-H4 dimers, forming two nearly symmetrical halves by tertiary structure. MacroH2A1, also known as H2AFY (H2A histone family, member Y), MacroH2A1.2, MacroH2A1.1, H2A/y, H2AFJ or mH2A1, is a 372 amino acid ubiquitously expressed nuclear histone variant that is enriched in inactive X chromosome chromatin and senescence-associated heterochromatin. Involved in augmentation of signal-regulated transcription, MacroH2A1 exists as three alternatively spliced isoforms, contains one histone H2A domain and a single Macro domain.
