Recovery from ultraviolet light-induced inhibition of DNA synthesis requires umuDC gene products in recA718 mutant strains but not in recA+ strains of Escherichia coli
Ultraviolet light (UV) inhibits DNA replication in Eschericia coli and induces the SOS response, a set of survival-enhancing phenotypes due to derepression of DNA damage-inducible genes, including recA and umuDC. Recovery of DNA synthesis after UV irradiation (induced replisome reactivation, or IRR) is an SOS function requiring RecA protein and postirradiation synthesis of additional protein(s), but this recovery does not require UmuDC protein. IRR occurs in strains carrying either recA718 (which does not reduce recombination, SOS inducibility, or UV mutagenesis) or umuC36 (which eliminates UV mutability), but not in recA718 umuC36 double mutants. In recA430 mutant strains, IRR does not occur whether or not functional UmuDC protein is present. IRR occurs in lexA-(Ind-) (SOS noninducible) strains if they carry an operator-constitutive recA allele and are allowed to synthesize proteins after irradiation. We conclude the following: (i) that UmuDC protein corrects or complements a defect in the ability of RecA718 protein (but not of RecA430 protein) to promote IRR and (ii) that in lexA(Ind-) mutant strains, IRR requires amplification of RecA+ protein (but not of any other LexA-repressed protein) plus post-UV synthesis of at least one other protein not controlled by LexA protein. We discuss the results in relation to the essential, but unidentified, roles of RecA and UmuDC proteins in UV mutagenesis.
- Research Organization:
- Rutgers, State Univ., Piscataway, NJ
- OSTI ID:
- 5623259
- Journal Information:
- Proc. Natl. Acad. Sci. U.S.A.; (United States), Vol. 84:19
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
DNA REPAIR
RADIOINDUCTION
ESCHERICHIA COLI
DNA REPLICATION
PROTEINS
BIOLOGICAL FUNCTIONS
BIOLOGICAL RECOVERY
DOSE-RESPONSE RELATIONSHIPS
GENES
GENETIC RADIATION EFFECTS
GENOTYPE
INHIBITION
ULTRAVIOLET RADIATION
BACTERIA
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
BIOLOGICAL REPAIR
ELECTROMAGNETIC RADIATION
FUNCTIONS
GENETIC EFFECTS
MICROORGANISMS
NUCLEIC ACID REPLICATION
ORGANIC COMPOUNDS
RADIATION EFFECTS
RADIATIONS
RECOVERY
REPAIR
560130* - Radiation Effects on Microorganisms