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The roles of the RecA protein in the SOS response of Escherichia coli: Isolation and analysis of recA mutants with novel SOS phenotypes

Thesis/Dissertation ·
OSTI ID:5525046
The RecA protein of Escherichia coli is a multifunctional protein which participates in DNA repair. The major goal of this study has been to explore the less well understood roles of the RecA protein in the restart of DNA synthesis at replication forks blocked by the presence of DNA damage (IRR), and in SOS mutagenesis. Toward this goal, several novel and interesting UV-resistant recA mutants have been isolated from the UV-sensitive recA430 strain, a mutant which is nonmutable and which this study has shown to be unable to promote IRR. Three of these mutants have been studied with respect to their abilities to promote various RecA functions: the recA720 mutant is of wild type UV resistance, UV-hypermutable in the presence of adenine at 42{degree}C and is a mutator in the presence of a lezA (Def) mutation, which inactivates the SOS repressor, and studies with this mutant have suggested that the RecA protein has a direct role in SOS mutagenesis. The recA727 mutant is of intermediate UV resistance to its recA430 parent and the recA{sup +} strain due to its partial ability to promote (IRR). This mutant also retains UV-nonmutability of the recA430 parent, but shows modest mutator activity in a lezA (Def) background, and studies with this mutant have suggested that the ability of the RecA protein to promote SOS mutagenesis and IRR cannot be separated by mutation. The recA725 mutant is as UV-resistant as the recA{sup +} strain and is somewhat less UV-mutable than the recA{sup +} strain, probably because it is only partially proficient in promoting the cleavage of the LexA repressor.
Research Organization:
Rutgers--the State Univ., New Brunswick, NJ (USA). Bureau of Engineering Research
OSTI ID:
5525046
Country of Publication:
United States
Language:
English

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Related Subjects

560130* -- Radiation Effects on Microorganisms
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ADENINES
AMINES
ANTIMETABOLITES
AROMATICS
AZAARENES
BACTERIA
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
DNA REPAIR
DNA REPLICATION
DRUGS
ELECTROMAGNETIC RADIATION
ESCHERICHIA COLI
HETEROCYCLIC COMPOUNDS
MICROORGANISMS
MUTAGENESIS
MUTANTS
NUCLEIC ACID REPLICATION
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHENOTYPE
PURINES
RADIATION INDUCED MUTANTS
RADIATIONS
RADIOSENSITIVITY
RECOVERY
REPAIR
ULTRAVIOLET RADIATION