A novel function of DNA polymerase zeta regulated by PCNA.
DNA polymerase zeta (Polzeta) participates in translesion DNA synthesis and is involved in the generation of the majority of mutations induced by DNA damage. The mechanisms that license access of Polzeta to the primer terminus and regulate the extent of its participation in genome replication are poorly understood. The Polzeta-dependent damage-induced mutagenesis requires monoubiquitination of proliferating cell nuclear antigen (PCNA) that is triggered by exposure to mutagens. We show that Polzeta contributes to DNA replication and causes mutagenesis not only in response to DNA damage but also in response to malfunction of normal replicative machinery due to mutations in replication genes. These replication defects lead to ubiquitination of PCNA even in the absence of DNA damage. Unlike damage-induced mutagenesis, the Polzeta-dependent spontaneous mutagenesis in replication mutants is reduced in strains defective in both ubiquitination and sumoylation of Lys164 of PCNA. Additionally, studies of a PCNA mutant defective for functional interactions with Polzeta, but not for monoubiquitination by the Rad6/Rad18 complex demonstrate a role for PCNA in regulating the mutagenic activity of Polzeta separate from its modification at Lys164.
Northam
Matthew R
MR
Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198, USA.
Garg
Parie
P
Baitin
Dmitri M
DM
Burgers
Peter M J
PM
Shcherbakova
Polina V
PV
D001483:Base Sequence; D004249:DNA Damage; D004261:DNA Replication / Q000235:genetics; D004271:DNA, Fungal / Q000235:genetics / Q000378:metabolism; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism; D005800:Genes, Fungal; D009154:Mutation; D010641:Phenotype; D018809:Proliferating Cell Nuclear Antigen / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D025841:Small Ubiquitin-Related Modifier Proteins / Q000378:metabolism; D025801:Ubiquitin / Q000378:metabolism; D014466:Ultraviolet Rays
D004271:DNA, Fungal; D018809:Proliferating Cell Nuclear Antigen; D029701:Saccharomyces cerevisiae Proteins; D025841:Small Ubiquitin-Related Modifier Proteins; D025801:Ubiquitin; C425929:DNA polymerase zeta; D004259:DNA-Directed DNA Polymerase