title: UV-induced mutagenesis of phage S13 can occur in the absence of the RecA and UmuC proteins of Escherichia coli.
abstract: The UV-induced mutagenesis of phage S13 that accompanies Weigle repair is known to require the products of the recA and umuDC genes, as does the UV-induced mutagenesis of the Escherichia coli chromosome. I found that UV-induced mutagenesis of phage S13 occurred in the absence of both the RecA and UmuC functions when the irradiated phage was photoreactivated. Furthermore, UV-induced phage mutations were produced in a recA- umuC- cell even without photoreactivation and in the absence of any other known UV repair mechanism, at a frequency 29% of that found after photoreactivation and 7% of that found after Weigle repair, implying that DNA synthesis can proceed past a dimer at an unexpectedly high frequency even when unaided by the UmuC-RecA SOS repair functions. The unaided DNA synthesis appears capable of producing mutations in the vicinity of a pyrimidine dimer; by aiding synthesis past a dimer, a repair mechanism may disclose a mutation without having any active role in producing it.
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology*; D003090:Coliphages / Q000235:genetics* / Q000502:physiology / Q000528:radiation effects; D011088:DNA Ligases / Q000235:genetics / Q000502:physiology*; D004260:DNA Repair; D004261:DNA Replication; D004277:DNA, Single-Stranded / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects; D004279:DNA, Viral / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects; D004255:Deoxyribodipyrimidine Photo-Lyase / Q000502:physiology; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics / Q000502:physiology*; D009154:Mutation; D011118:Polynucleotide Ligases / Q000502:physiology*; D011740:Pyrimidine Dimers / Q000235:genetics / Q000378:metabolism; D011938:Rec A Recombinases / Q000235:genetics / Q000502:physiology*; D014466:Ultraviolet Rays; D014779:Virus Replication
chemical_list: D001426:Bacterial Proteins; D004277:DNA, Single-Stranded; D004279:DNA, Viral; D011740:Pyrimidine Dimers; D011938:Rec A Recombinases; D004255:Deoxyribodipyrimidine Photo-Lyase; D011088:DNA Ligases; D011118:Polynucleotide Ligases