A four-subunit DNA polymerase zeta complex containing Pol delta accessory subunits is essential for PCNA-mediated mutagenesis

作者：Makarova Alena V; Stodola Joseph L; Burgers Peter M^*

来源：Nucleic Acids Research, 2012, 40(22): 11618-11626.

DOI：10.1093/nar/gks948

DNA polymerase zeta (Pol zeta) plays a key role in DNA translesion synthesis (TLS) and mutagenesis in eukaryotes. Previously, a two-subunit Rev3-Rev7 complex had been identified as the minimal assembly required for catalytic activity in vitro. Herein, we show that Saccharomyces cerevisiae Pol zeta binds to the Pol31 and Pol32 subunits of Pol delta, forming a four-subunit Pol zeta(4) complex (Rev3-ev7-Pol31-Pol32). A [4Fe-4S] cluster in Rev3 is essential for the formation of Pol zeta(4) and damage-induced mutagenesis. Pol32 is indispensible for complex formation, providing an explanation for the long-standing observation that pol32 Delta strains are defective for mutagenesis. The Pol31 and Pol32 subunits are also required for proliferating cell nuclear antigen (PCNA)-dependent TLS by Pol zeta as Pol zeta(2) lacks functional interactions with PCNA. Mutation of the C-terminal PCNA-interaction motif in Pol32 attenuates PCNA-dependent TLS in vitro and mutagenesis in vivo. Furthermore, a mutant form of PCNA, encoded by the mutagenesis-defective pol30-113 mutant, fails to stimulate Pol zeta(4) activity, providing an explanation for the observed mutagenesis phenotype. A stable Pol zeta(4) complex can be identified in all phases of the cell cycle suggesting that this complex is not regulated at the level of protein interactions between Rev3-Rev7 and Pol31-Pol32.

• 出版日期2012-12