Role of deoxyribonucleic acid polymerases and deoxyribonucleic acid ligase in x-ray-induced repair synthesis in toluene-treated Escherichia coli K-12
Toluene-treated Escherichia coli mutants have been used to study the roles of deoxyribonucleic acid (DNA) polymerases I, II, and III, and of DNA ligase in repair synthesis and strand rejoining following X-irradiation. In cells possessing all three DNA polymerases, both a greater amount of repair synthesis (''exaggerated'' repair synthesis) and failure of ligation are observed when DNA ligase activity is inhibited. In a mutant lacking the polymerizing activity of DNA polymerase I, exaggerated repair synthesis is not observed, and strand rejoining does not occur even if DNA ligase is fully activated. In a mutant possessing the polymerizing activity of DNA polymerase I but lacking its 5' ..-->.. 3' exonuclease activity, exaggerated repair synthesis is minimal. After irradiation, DNA polymerases II and III are capable of carrying out an adenosine 5'-triphosphate-dependent repair synthesis, but rejoining of strand breaks does not occur and exaggerated synthesis is not seen whether DNA ligase is active or not. These results suggest that DNA polymerase I and DNA ligase act together to limit repair synthesis after X irradiation and that both are necessary in toluene-treated cells for strand rejoining. DNA polymerases II and III apparently cannot complete chain elongation and gap filling, and therefore repair carried out by these enzymes does not respond to ligase action.
- Research Organization:
- Oak Ridge National Lab., TN
- OSTI ID:
- 7223067
- Journal Information:
- J. Bacteriol.; (United States), Journal Name: J. Bacteriol.; (United States) Vol. 126:2; ISSN JOBAA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
AROMATICS
BACTERIA
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
DNA
DNA REPLICATION
ELECTROMAGNETIC RADIATION
ENZYMES
ESCHERICHIA COLI
HYDROCARBONS
IONIZING RADIATIONS
LIGASES
MICROORGANISMS
MUTANTS
NUCLEIC ACID REPLICATION
NUCLEIC ACIDS
ORGANIC COMPOUNDS
POLYMERASES
RADIATION EFFECTS
RADIATIONS
RECOVERY
REPAIR
STRAND BREAKS
TOLUENE
X RADIATION