Atypical histone H2A which can replace conventional H2A in some nucleosomes and is associated with active transcription and mRNA processing . Nucleosomes wrap and compact DNA into chromatin, limiting DNA accessibility to the cellular machineries which require DNA as a template. Histones thereby play a central role in transcription regulation, DNA repair, DNA replication and chromosomal stability (   ). Nucleosomes containing this histone are less rigid and organize less DNA than canonical nucleosomes in vivo ( , ). They are enriched in actively transcribed genes and associate with the elongating form of RNA polymerase (, ). They associate with spliceosome components and are required for mRNA splicing .
Subcellular locations: Nucleus, Chromosome
Associated with the active X chromosome and with autosomes, while it is absent from the inactive X chromosome and excluded from Barr bodies.
Present in mature sperm.