Nir Heyman S, Golan M, Liefshitz B, Kupiec M

Several DNA polymerases participate in DNA synthesis during genome replication and DNA repair. PCNA, a homotrimeric ring, acts as a processivity factor for DNA polymerases. PCNA also acts as a "landing pad" for proteins that interact with chromatin and DNA at the moving fork. The interaction between PCNA and polymerase ...

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delta (Pol?) is mediated by PIPs (PCNA-interacting peptides), in particular the one on Pol32, a regulatory subunit of Pol?. Here, we demonstrate that pol3-01, an exonuclease mutant of Pol?'s catalytic subunit, exhibits a weak interaction with Pol30 compared to the WT DNA polymerase. The weak interaction activates DNA bypass pathways, leading to increased mutagenesis and sister chromatid recombination. Strengthening pol3-01's weak interaction with PCNA suppresses most of the phenotypes. Our results are consistent with a model in which Pol3-01 tends to detach from the chromatin, allowing an easier replacement of Pol? by the trans-lesion synthesis polymerase Zeta (Polz), thus leading to the increased mutagenic phenotype.

Date: Feb. 02, 2023

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