title: Repair of ultraviolet-light damaged ColE1 factor carrying Escherichia coli genes for guanine synthesis.
abstract: Hybrid ColE1 plasmids called ColE1-coslambda-qua A or ColE1-coslambda-gal can be efficiently tranduced into various E. coli K-12 cells through packaging into lambda phage particles. Using these plasmids, repair of ultraviolet-light (UV) damaged ColE1 DNAs was studied in various UV sensitive E. coli K-12 mutants. (1) The host mutations uvrA and uvrB markedly reduced host-cell reactivation of UV-irradiated ColE1-coslambda-guaA. (2) Pre-existing hybrid ColE1 plasmids had no effect on the frequency of lambda phage-mediated transduction of another differentially marked hybrid ColE1 DNAs. (3) ColE1-coslambda-guaA and ColE1-coslambda-gal DNAs could temporarily but not stably co-exist in E. coli K-12 recA cells. (4) The presence of ColE1-coslambda-gal in uvrB cells promoted the repair of super-infected UV-irradiated ColE1-coslambda-guaA about 7-fold. (5) The same ColE1-coslambda-gal plasmid in a uvrB recA double mutant did not have this promoting effect. These results indicate that the effect of resident hybrid ColE1 plasmids is manifested by the host recA+ gene function(s) and suggest that ColE1 plasmid itself provides norecA+-like functions.
mesh_terms: D002874:Chromosome Mapping; D003090:Coliphages / Q000235:genetics; D004260:DNA Repair; D004269:DNA, Bacterial / Q000378:metabolism / Q000528:radiation effects; D004274:DNA, Recombinant; D004926:Escherichia coli / Q000235:genetics* / Q000528:radiation effects; D005796:Genes; D006147:Guanine / Q000096:biosynthesis*; D009154:Mutation; D010957:Plasmids / Q000528:radiation effects; D011995:Recombination, Genetic; D014161:Transduction, Genetic; D014466:Ultraviolet Rays
chemical_list: D004269:DNA, Bacterial; D004274:DNA, Recombinant; D006147:Guanine