H2AX is one of the histone proteins that is systematically found and ubiquitously distributed throughout the genome. DNA double-strand breaks (DSBs) induce rapid phosphorylation of H2AX (142 amino acids) at serine 139, a highly conserved serine residue located in the C-terminus.
In eukaryotes, DNA is highly condensed and packaged into chromatin within the nuclei. This condensed chromatin forms a structural barrier for DNA processing during DNA repair, replication, transcription, and recombination. A fundamental subunit of the chromosome is the nucleosome, which is composed of 146 bp of DNA wrapped in two complete turns around an octamer of the core histones H2A, H2B, H3, and H4, and there are varying lengths of linker DNA connecting these subunits. The core histone octamer forms a 100-kDa protein complex. Histone H2A has been conserved throughout eukaryotic evolution. There are three H2A subfamilies:...