Biolegend, 600205, Alexa Fluor® 647 anti-H2A.X Antibody

Histone subunit H2A, along with subunits 2B, 3, and 4, make up the core subunits of the nucleosome octomer. An octomer contains two protomers of each subunit tightly wrapped around a ~147 bp segment of DNA. Histones have integral roles in chromatin integrity, genomic stability, and gene regulation. Post-translational modification of histones in response to certain stimuli results in alterations of nucleosomal positioning relative to DNA. Histone H2A.X is a non-allelic variant of Histone 2A that harbors a C-terminal extension and is essential for checkpoint mediated cell cycle arrest and DNA double-stranded break (DSB) repair in response to both endogenous and exogenous agents, as well as meiotic recombination events and immunoglobulin class switching in lymphocytes. Phosphorylation of C-terminal residue serine 139 by ATM (γ-H2A.X) results in the recruitment of DSB-repair machinery. Phopshorylation of H2A.X is also critical for chromatin fragmentation during apoptosis.