Histone H2A is a 14 kD nuclear protein that is a component of an octamer containing pairs of each of four core histones (H2A, H2B, H3, H4). The core histones create nucleosome structure of chromosomal fiber in eukaryotes and are dynamic in gene regulation. The histones exhibit cell cycle-dependent transcriptional regulation. Histone H2A can be modified by phosphorylation and acetylation; phosphorylation of H2A correlates with mitotic chromosome condensation. Histone H2A interacts with Histones H3B, H3, and H4 as well as HIV-1 Tat peptides. The Poly6194 antibody has been shown to be useful for the Western blotting of human histone 2A.