Differential Roles for DNA Polymerases Eta, Zeta, and REV1 in Lesion Bypass of Intrastrand versus Interstrand DNA Cross-Links

Abstract

Translesion DNA synthesis (TLS) is a process whereby specialized DNA polymerases are recruited to bypass DNA lesions that would otherwise stall high-fidelity polymerases. We provide evidence that TLS across cisplatin intrastrand cross-links is performed by multiple translesion DNA polymerases. First, we determined that PCNA monoubiquitination by RAD18 is necessary for efficient bypass of cisplatin adducts by the TLS polymerases eta (Polη), REV1, and zeta (Polζ) based on the observations that depletion of these proteins individually leads to decreased cell survival, cell cycle arrest in S phase, and activation of the DNA damage response. Second, we showed that in addition to PCNA monoubiquitination by RAD18, the Fanconi anemia core complex is also important for recruitment of REV1 to stalled replication forks in cisplatin treated cells. Third, we present evidence that REV1 and Polζ are uniquely associated with protection against cisplatin and mitomycin C-induced chromosomal aberrations, and both are necessary for the timely resolution of DNA double-strand breaks associated with repair of DNA interstrand cross-links. Together, our findings indicate that REV1 and Polζ facilitate repair of interstrand cross-links independently of PCNA monoubiquitination and Polη, whereas RAD18 plus Polη, REV1, and Polζ are all necessary for replicative bypass of cisplatin intrastrand DNA cross-links.

Supplemental material for this article may be found at http://mcb.asm.org/.

We thank Martin Arlt, David Ferguson, JoAnn Sekiguchi, and Mats Ljungman for helpful discussions and Julia Brennan for technical assistance.

This research was supported by a grant from the National Institutes of Health (CA133046 to C.E.C.), through a University of Michigan's Cancer Center Support Grant (5 P30 CA46592), and by a grant from NIGMS (GM007767 to J.K.H.).

The contents of this study are solely the responsibility of the authors and do not necessarily represent the official views of the National Institute of General Medical Sciences.