title: Defect of Fe-S cluster binding by DNA polymerase δ in yeast suppresses UV-induced mutagenesis, but enhances DNA polymerase ζ - dependent spontaneous mutagenesis.
abstract: Eukaryotic genomes are duplicated by a complex machinery, utilizing high fidelity replicative B-family DNA polymerases (pols) α, δ and ε. Specialized error-prone pol ζ, the fourth B-family member, is recruited when DNA synthesis by the accurate trio is impeded by replication stress or DNA damage. The damage tolerance mechanism dependent on pol ζ prevents DNA/genome instability and cell death at the expense of increased mutation rates. The pol switches occurring during this specialized replication are not fully understood. The loss of pol ζ results in the absence of induced mutagenesis and suppression of spontaneous mutagenesis. Disruption of the Fe-S cluster motif that abolish the interaction of the C-terminal domain (CTD) of the catalytic subunit of pol ζ with its accessory subunits, which are shared with pol δ, leads to a similar defect in induced mutagenesis. Intriguingly, the pol3-13 mutation that affects the Fe-S cluster in the CTD of the catalytic subunit of pol δ also leads to defective induced mutagenesis, suggesting the possibility that Fe-S clusters are essential for the pol switches during replication of damaged DNA. We confirmed that yeast strains with the pol3-13 mutation are UV-sensitive and defective in UV-induced mutagenesis. However, they have increased spontaneous mutation rates. We found that this increase is dependent on functional pol ζ. In the pol3-13 mutant strain with defective pol δ, there is a sharp increase in transversions and complex mutations, which require functional pol ζ, and an increase in the occurrence of large deletions, whose size is controlled by pol ζ. Therefore, the pol3-13 mutation abrogates pol ζ-dependent induced mutagenesis, but allows for pol ζ recruitment for the generation of spontaneous mutations and prevention of larger deletions. These results reveal differential control of the two major types of pol ζ-dependent mutagenesis by the Fe-S cluster present in replicative pol δ.
authors.affiliation: Department of Genetics and Biotechnology, Saint-Petersburg State University, St. Petersburg, Russia; Saint-Petersburg Branch of Vavilov Institute of General Genetics, Russian Academy of Sciences, St. Petersburg, Russia; Eppley Institute for Research in Cancer, University of Nebraska Medical Center, USA.
authors.forename: E I
authors.initials: EI
authors.lastname: Stepchenkova
authors.affiliation: Department of Plant Physiology and Biochemistry, Saint-Petersburg State University, St. Petersburg, Russia.
authors.forename: E R
authors.initials: ER
authors.lastname: Tarakhovskaya
authors.affiliation: Eppley Institute for Research in Cancer, University of Nebraska Medical Center, USA.
authors.forename: H M
authors.initials: HM
authors.lastname: Siebler
authors.affiliation: Eppley Institute for Research in Cancer, University of Nebraska Medical Center, USA; Departments of Pathology and Microbiology, Biochemistry and Molecular Biology, Genetics and Anatomy, University of Nebraska Medical Center, USA. Electronic address: ypavlov@unmc.edu.
authors.forename: Y I
authors.initials: YI
authors.lastname: Pavlov
mesh_terms: D020816:Amino Acid Motifs; D020134:Catalytic Domain; D004258:DNA Polymerase III / Q000235:genetics / Q000378:metabolism*; D004261:DNA Replication; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism; D016296:Mutagenesis; D009154:Mutation; D059645:Mutation Rate; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D029701:Saccharomyces cerevisiae Proteins; C425929:DNA polymerase zeta; D004258:DNA Polymerase III; D004259:DNA-Directed DNA Polymerase
keywords: DNA polymerases; Fe-S clusters; Induced and spontaneous mutagenesis