Histone Variant H3.3: A versatile H3 variant in health and in disease

Histones are the main protein components of eukaryotic chromatin. Histone variants and histone modifications modulate chromatin structure, ensuring the precise operation of cellular processes associated with genomic DNA. H3.3, an ancient and conserved H3 variant, differs from its canonical H3 counterpart by only five amino acids, yet it plays essential and specific roles in gene transcription, DNA repair and in maintaining genome integrity. Here, we review the most recent insights into the functions of histone H3.3, and the involvement of its mutant forms in human diseases.