Mouse Rev1 protein interacts with multiple DNA polymerases involved in translesion DNA synthesis

Polkappa and Rev1 are members of the Y family of DNA polymerases involved in tolerance to DNA damage by replicative bypass [translesion DNA synthesis (TLS)]. We demonstrate that mouse Rev1 protein physically associates with Polkappa. We show too that Rev1 interacts independently with Rev7 (a subunit of a TLS polymerase, Polzeta) and with two other Y-family polymerases, Poliota and Poleta. Mouse Polkappa, Rev7, Poliota and Poleta each bind to the same similar to100 amino acid C-terminal region of Rev1. Furthermore, Rev7 competes directly with Polkappa for binding to the Rev1 C-terminus. Notwith standing the physical interaction between Rev1 and Polkappa, the DNA polymerase activity of each measured by primer extension in vitro is unaffected by the complex, either when extending normal primer-termini, when bypassing a single thymine glycol lesion, or when extending certain mismatched primer termini. Our observations suggest that Rev1 plays a role(s) in mediating protein-protein interactions among DNA polymerases required for TLS. The precise function(s) of these interactions during TLS remains to be determined.