Histone H3.3 (family member 3B) (H3-3B)

Histone H3.3 (family member 3B), encoded by the H3F3B gene, is a highly conserved histone variant involved in the formation of nucleosomes, the fundamental units of chromatin in eukaryotic cells[1][3]. Unlike canonical histone H3 (e.g., H3.1, H3.2), H3.3 is incorporated into chromatin independently of DNA replication and throughout the cell cycle by specialized histone chaperones (notably HIRA and DAXX complexes)[1][4]. H3.3 is found at actively transcribed regions, regulatory elements, and also in certain types of heterochromatin, participating in the dynamic regulation of gene expression, epigenetic memory, DNA repair, and chromosomal stability[1][2][4]. Mutations in H3-3B and its paralog H3F3A are implicated in various cancers (as driver mutations) and some neurodevelopmental syndromes[2][3][4]. No direct drugs target histone H3.3 clinically due to its fundamental role in chromatin integrity and cellular homeostasis.

Other names

H3.3 histone BHistone H3.3H3-3AH3.3AH3F3H3F3AH3.3BH3F3BPP781BRYLIB2H3 histone family member 3BH3 histone, family 3B (H3.3B)

not applicable (no drugs listed); in cancer, disease often results from gain- or loss-of-function mutations affecting chromatin states rather than direct pharmacological modulation[4]