Apurinic/Apyrimidinic Endonuclease 2 (APEX2)

APEX2 is a member of the apurinic/apyrimidinic (AP) family of endonucleases that initiate the repair of AP sites formed by spontaneous hydrolysis of the N-glycosylic bond, mutagen-induced base release, or damaged-base excision by a DNA repair glycosylase. The deduced 518-amino acid protein has a calculated molecular mass of 59.1 kD. APEX2 contains a predicted N-terminal mitochondrial targeting sequence, a C-terminal region that shares homology with S. cerevisiae APN2/ETH1, a putative PCNA-binding motif, and a C-terminal subregion that is homologous to a tandem repeat in the C-terminal region of DNA topoisomerase III family proteins. RT-PCR detected APEX2 expression in HeLa cells, Jurkat cells, and human kidney, brain and fetal brain tissue.