title: Involvement of specialized DNA polymerases Pol II, Pol IV and DnaE2 in DNA replication in the absence of Pol I in Pseudomonas putida.
abstract: The majority of bacteria possess a different set of specialized DNA polymerases than those identified in the most common model organism Escherichia coli. Here, we have studied the ability of specialized DNA polymerases to substitute Pol I in DNA replication in Pseudomonas putida. Our results revealed that P. putida Pol I-deficient cells have severe growth defects in LB medium, which is accompanied by filamentous cell morphology. However, growth of Pol I-deficient bacteria on solid rich medium can be restored by reduction of reactive oxygen species in cells. Also, mutants with improved growth emerge rapidly. Similarly to the initial Pol I-deficient P. putida, its adapted derivatives express a moderate mutator phenotype, which indicates that DNA replication carried out in the absence of Pol I is erroneous both in the original Pol I-deficient bacteria and the adapted derivatives. Analysis of the spectra of spontaneous Rif(r) mutations in P. putida strains lacking different DNA polymerases revealed that the presence of specialized DNA polymerases Pol II and Pol IV influences the frequency of certain base substitutions in Pol I-proficient and Pol I-deficient backgrounds in opposite ways. Involvement of another specialized DNA polymerase DnaE2 in DNA replication in Pol I-deficient bacteria is stimulated by UV irradiation of bacteria, implying that DnaE2-provided translesion synthesis partially substitutes the absence of Pol I in cells containing heavily damaged DNA.
authors.affiliation: Department of Genetics, Tartu University and Estonian Biocentre, Tartu, Estonia.
authors.forename: Julia
authors.initials: J
authors.lastname: Sidorenko
authors.forename: Tatjana
authors.initials: T
authors.lastname: Jatsenko
authors.forename: Signe
authors.initials: S
authors.lastname: Saumaa
authors.forename: Riho
authors.initials: R
authors.lastname: Teras
authors.forename: Mariliis
authors.initials: M
authors.lastname: Tark-Dame
authors.forename: Rita
authors.initials: R
authors.lastname: Hõrak
authors.forename: Maia
authors.initials: M
authors.lastname: Kivisaar
mesh_terms: D001426:Bacterial Proteins / Q000502:physiology*; D004249:DNA Damage; D004256:DNA Polymerase I / Q000235:genetics / Q000378:metabolism*; D004257:DNA Polymerase II / Q000378:metabolism*; D004258:DNA Polymerase III / Q000378:metabolism*; D019951:DNA Polymerase beta / Q000378:metabolism*; D004260:DNA Repair; D004261:DNA Replication; D009154:Mutation; D016958:Pseudomonas putida / Q000235:genetics / Q000254:growth & development / Q000378:metabolism* / Q000528:radiation effects; D011836:Radiation Tolerance; D017382:Reactive Oxygen Species / Q000494:pharmacology; D014466:Ultraviolet Rays
chemical_list: D001426:Bacterial Proteins; D017382:Reactive Oxygen Species; C074904:DNA polymerase III, alpha subunit; D004256:DNA Polymerase I; D004257:DNA Polymerase II; D004258:DNA Polymerase III; D019951:DNA Polymerase beta