Deoxyribonucleic acid repair in vitro by extracts of Escherichia coli
Deoxyribonucleic acid (DNA) from bacteriophage T7 has been used to monitor the capacity of gently lysed extracts of Escherichia coli to perform repair resynthesis after ultraviolet (uv) irradiation. Purified DNA damaged by up to 100 J of uv radiation per m/sup 2/ was treated with an endonuclease from Micrococcus luteus that introduces single-strand breaks in irradiated DNA. This DNA was then used as a substrate to study repair resynthesis by extracts of E. coli. It was found that incubation with the extract and exogenous nucleoside triphosphates under suitable assay conditions resulted in removal of all pyrimidine dimers and restoration of the substrate DNA to its original molecular weight. Repair resynthesis, detected as nonconservative, uv-stimulated DNA synthesis, was directly proportional to the number of pyrimidine dimers introduced by radiation. The repair mode described here appears to require DNA polymerase I since it does not occur at the restrictive temperature in polA12 mutants, which contain a thermolabile polymerase. The addition of purified DNA polymerase I to extracts made from a polA mutant restores the ability to complete repair at the restrictive temperature.
- Research Organization:
- Oak Ridge National Lab., TN
- OSTI ID:
- 5680372
- Journal Information:
- J. Bacteriol.; (United States), Journal Name: J. Bacteriol.; (United States) Vol. 129:3; ISSN JOBAA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
560400 -- Other Environmental Pollutant Effects
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
AZINES
BACTERIA
BACTERIOPHAGES
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
BIOSYNTHESIS
CHEMICAL REACTIONS
DIMERS
DNA
ELECTROMAGNETIC RADIATION
ENZYMES
ESCHERICHIA COLI
HETEROCYCLIC COMPOUNDS
MICROCOCCUS
MICROCOCCUS LUTEUS
MICROORGANISMS
MONITORING
NUCLEASES
NUCLEIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PARASITES
PHOSPHOTRANSFERASES
POLYMERASES
POLYMERIZATION
PYRIMIDINES
RADIATIONS
RECOVERY
REPAIR
STRAND BREAKS
SYNTHESIS
TRANSFERASES
ULTRAVIOLET RADIATION
VIRUSES