Histone H3.3
1_MARTK 6_ QTARK 11_ STGGK 16_ APRKQ 21_ LATKA 26_ ARKSA 31_ PSTGG 36_ VKKPH 41_ RYRPG 46_ TVALR 51_ EIRRY 56_ QKSTE 61_ LLIRK 66_ LPFQR 71_ LVREI 76_ AQDFK 81_ TDLRF 86_ QSAAI 91_ GALQE 96_ ASEAY 101_ LVGLF 106_ EDTNL 111_ CAIHA 116_ KRVTI 121_ MPKDI 126_ QLARR 131_IRGER
1: Variant histone H3 which replaces conventional H3 in a wide range of nucleosomes in active genes. Constitutes the predominant form of histone H3 in non-dividing cells and is incorporated into chromatin independently of DNA synthesis. Deposited at sites of nucleosomal displacement throughout transcribed genes, suggesting that it represents an epigenetic imprint of transcriptionally active chromatin. 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