Anti-Histone H3.3

Histones are major chromatin proteins involved in nucleosome assembly. Their major function is to compact long DNA strands inside the nucleus and chromatin regulation. Histone H3.3 is a replication independent variant of Histone H3 which is generally expressed in quiescent or terminally differentiated cells. Modifications in Histone H3.3 are associated with transcriptional activation and acts as an epigenetic mark of transcriptionally active chromatin. Histone H3.3 is a 15 kDa protein which is expressed throughout the cell cycle independently of DNA synthesis in all eukaryotic genomes. Protein function: 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. [The UniProt Consortium]