FUNCTION Core component of nucleosome. 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. DNA accessibility is regulated via a complex set of post-translational modifications of histones, also called histone code, and nucleosome remodeling.
SUBUNIT STRUCTURE The nucleosome is a histone octamer containing two molecules each of H2A, H2B, H3 and H4 assembled in one H3-H4 heterotetramer and two H2A-H2B heterodimers. The octamer wraps approximately 147 bp of DNA.
SUBCELLULAR LOCATION Nucleus.
TISSUE SPECIFICTY Expressed in testicular cells.
DEVELOPMENTAL STAGE Expressed during S phase, then expression strongly decreases as cell division slows down during the process of differentiation.
Post-translational modification Acetylation is generally linked to gene activation. Acetylation on Lys-10 impairs methylation at Arg-9. Acetylation on Lys-19 and Lys-24 favors methylation at Arg-18 By similarity.
Citrullination at Arg-9 and/or Arg-18 by PADI4 impairs methylation and represses transcription By similarity.
Asymmetric dimethylation at Arg-18 by CARM1 is linked to gene activation. Symmetric dimethylation at Arg-9 by PRMT5 is linked to gene repression By similarity.
Methylation at Lys-5, Lys-37 and Lys-80 are linked to gene activation. Methylation at Lys-5 facilitates subsequent acetylation of H3 and H4. Methylation at Lys-80 is associated with DNA double-strand break (DSB) responses and is a specific target for TP53BP1. Methylation at Lys-10 and Lys-28 are linked to gene repression. Methylation at Lys-10 is a specific target for HP1 proteins (CBX1, CBX3 and CBX5) and prevents subsequent phosphorylation at Ser-11 and acetylation of H3 and H4. Methylation at Lys-5 and Lys-80 require preliminary monoubiquitination of H2B at 'Lys-120'. Methylation at Lys-10 and Lys-28 are enriched in inactive X chromosome chromatin By similarity.
Phosphorylated at Thr-4 by GSG2/haspin during prophase and dephosphorylated during anaphase. At centromeres, specifically phosphorylated at Thr-12 from prophase to early anaphase. Phosphorylated at Ser-11 during the whole mitosis. Phosphorylation at Ser-11, which is linked to gene activation, prevents methylation at Lys-10 but facilitates acetylation of H3 and H4. Phosphorylated at Ser-29 by MLTK isoform 1, RPS6KA5 or AURKB during mitosis or upon ultraviolet B irradiation By similarity.
Phosphorylation at 'Ser-11' is crucial for chromosome condensation and cell-cycle progression during mitosis and meiosis. In addition phosphorylation at 'Ser-11' is important during interphase because it enables the transcription of genes following external stimulation, like stress or growth factors. Phosphorylation at 'Ser-11' is also an essential regulatory mechanism for neoplastic cell transformation. Phosphorylation at 'Ser-11' by AURKB/Aurora-B mediates the dissociation of HP1 proteins (CBX1, CBX3 and CBX5) from heterochromatin.
Ubiquitinated By similarity.
SEQUENCE SIMILARITIES Belongs to the histone H3 family.