Artemis is a widely expressed 78 kD protein involved in non-homologous end joining. This protein has been reported to be involved in DNA double-strand break repair and the processing of hairpin coding ends during VDJ recombination. Artemis has endonuclease and exonuclease activity and has been shown to be mutated in human severe combined immune deficiency disorder (T-B- radiosensitive SCID). Artemis is phosphorylated by DNA-PKcs; phosphorylation regulates intrinsic endonuclease and exonuclease activity. Artemis has been shown to form a complex with DNA-PKcs. The Poly6198 antibody has been shown to be useful for Western blotting of the human Artemis protein.