Interactions between epsilon, the proofreading subunit of DNA polymerase III, and proteins involved in the SOS response of Escherichia coli.
Epsilon, a fidelity subunit of Escherichia coli DNA Polymerase III, is encoded by dnaQ+. dnaQ49 is a recessive allele that confers temperature-sensitive and salt-suppressible phenotypes for both replication fidelity and viability. SOS mutagenesis in E. coli is regulated by LexA and requires activated RecA (RecA*) and the products of the umuDC operon. dnaQ49 strains with various recA, lexA and umuDC alleles were constructed to determine if activities induced as part of the SOS response influence epsilon activity. We found: (1) both UmuDC and RecA* independently enhance the dnaQ49 mutator phenotype, and (2) expression of RecA* activity in the absence of UmuDC function increases the temperature sensitivity for viability of dnaQ49. These results support the hypothesis that RecA and one or both of the UmuDC proteins interact with the replication complex during SOS mutagenesis.
Foster
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PL
Division of Environmental Health, Boston University School of Public Health, MA.
Sullivan
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D000483:Alleles; D001426:Bacterial Proteins / Q000235:genetics; D004258:DNA Polymerase III / Q000235:genetics*; D004260:DNA Repair; D004259:DNA-Directed DNA Polymerase / Q000235:genetics*; D029968:Escherichia coli Proteins; D005798:Genes, Bacterial; D005838:Genotype; D009154:Mutation; D010641:Phenotype; D011938:Rec A Recombinases / Q000235:genetics*; D012097:Repressor Proteins / Q000235:genetics; D013014:SOS Response, Genetics; D012697:Serine Endopeptidases; D012965:Sodium Chloride / Q000494:pharmacology; D013696:Temperature; D000099160:LexA Repressor Protein
D001426:Bacterial Proteins; D004258:DNA Polymerase III; D004259:DNA-Directed DNA Polymerase; D029968:Escherichia coli Proteins; D011938:Rec A Recombinases; D012097:Repressor Proteins; D012697:Serine Endopeptidases; D012965:Sodium Chloride; D000099160:LexA Repressor Protein; C055218:UmuD protein, E coli