Polymerase DNA Directed Nu (POLn)

POLN is predicted to contain a fingers-thumb-palm structure conserved in the PolA family. Northern blot analysis of human tissues detected an approximately 4-kb transcript in testis, heart, and skeletal muscle, and a 2-kb transcript in heart, liver, skeletal muscle, kidney, and pancreas. The 2-kb transcript was detected in a panel of human cancer cell lines, and the 4-kb transcript was detected only in a chronic myelogenous leukemia cell line. Both POLN and DNA helicase HEL308 showed high expression in human and mouse testis. In situ hybridization of mouse testis tissue localized the highest Poln expression to meiotic spermatocytes and postmeiotic round spermatids, while Hel308 expression occurred in primary spermatocytes but was not detected in round spermatids.