Primate-specific variant histone H3, which constitutes a core component of nucleosomes (PubMed:20819935). 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 (Probable). 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 (PubMed:20819935). The octamer wraps approximately 147 bp of DNA (Probable). Expressed at low level in some tissues, such as testis and brain. Acetylation is generally linked to gene activation. Acetylation on Lys-10 (H3K9ac) impairs methylation at Arg-9 (H3R8me2s). Acetylation on Lys-19 (H3K18ac) and Lys-24 (H3K24ac) favors methylation at Arg-18 (H3R17me). Citrullination at Arg-9 (H3R8ci) and/or Arg-18 (H3R17ci) impairs methylation and represses transcription. Asymmetric dimethylation at Arg-18 (H3R17me2a) is linked to gene activation. Symmetric dimethylation at Arg-9 (H3R8me2s) is linked to gene repression. Asymmetric dimethylation at Arg-3 (H3R2me2a) is linked to gene repression and is mutually exclusive with H3 Lys-5 methylation (H3K4me2 and H3K4me3). H3R2me2a is present at the 3' of genes regardless of their transcription state and is enriched on inactive promoters, while it is absent on active promoters. Methylation at Lys-5 (H3K4me) facilitates subsequent acetylation of H3 and H4. Methylation at Lys-10 (H3K9me) and Lys-28 (H3K27me), which are linked to gene repression, are underrepresented. Methylation at Lys-10 (H3K9me) is a specific target for HP1 proteins (CBX1, CBX3 and CBX5) and prevents subsequent acetylation of H3 and H4. Phosphorylation at Thr-7 (H3T6ph) is a specific tag for epigenetic transcriptional activation that prevents demethylation of Lys-5 (H3K4me) by LSD1/KDM1A. At centromeres, specifically phosphorylated at Thr-12 (H3T11ph) from prophase to early anaphase. Phosphorylation at Thr-12 (H3T11ph) is a specific tag for epigenetic transcriptional activation that promotes demethylation of Lys-10 (H3K9me). Phosphorylation at Tyr-42 (H3Y41ph) promotes exclusion of CBX5 (HP1 alpha) from chromatin. Lysine deamination at Lys-5 (H3K4all) to form allysine. Allysine formation only takes place on H3K4me3 and results in gene repression. Crotonylation (Kcr) is specifically present in male germ cells and marks testis-specific genes in post-meiotic cells, including X-linked genes that escape sex chromosome inactivation in haploid cells. Crotonylation marks active promoters and enhancers and confers resistance to transcriptional repressors. It is also associated with post-meiotically activated genes on autosomes. Butyrylation of histones marks active promoters and competes with histone acetylation. It is present during late spermatogenesis. Belongs to the histone H3 family. Could be the product of a pseudogene.