We describe here two novel mouse and human DNA polymerases: one (pol λ) has homology with DNA polymerase β while the other one (pol µ) is closer to terminal deoxynucleotidyltransferase. However both have DNA polymerase activity in vitro and share similar structural organization, including a BRCT domain, helix-loop-helix DNA-binding motifs and polymerase X domain. mRNA expression of pol λ is highest in testis and fetal liver, while expression of pol µ is more lymphoid, with highest expression both in thymus and tonsillar B cells. An unusually large number of splice variants is observed for the pol µ gene, most of which affect the polymerase domain. Expression of mRNA of both polymerases is downregulated upon treatment by DNA damaging agents (UV light, γ-rays or H 2 O 2 ). This suggests that their biological function may differ from DNA translesion synthesis, for which several DNA polymerase activities have been recently described. Possible functions are discussed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.