Abstract
Translesion DNA synthesis is essential for the maintenance of chromosomal integrity as well as the DNA repair function. It has been suggested that functions of the REV genes are required for translesion DNA synthesis, essential for induction of mutations and prevention of cell death caused by ionizing radiation. REV1 is the deoxycytidyl transferase and forms a stable heterodimer with REV7. Recently, it has been found that the REV1 interacts with all of the Y-family DNA polymerases, pol eta, iota and kappa, suggesting the central role of REV1 in the translesion DNA synthesis.
We document a novel biochemical activity of human REV1 protein, which is due to higher affinity for single stranded DNA (ssDNA) than the primer terminus. After preferential binding to long ssDNA regions of the template strand, REV1 is targeted specifically to the included primer termini. Importantly, this property is not shared by other DNA polymerases, including human DNA polymerases eta, iota and kappa. Further, a mutant REV1 lacking N- and C-terminal domains lost only this function, indicating regulatory role of the both domains. The novel activity of REV1 protein might imply a role for ssDNA in regulation of translesion DNA synthesis.
