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U.S. Department of Energy
Office of Scientific and Technical Information

Effects of radiations on DNA and repair of the damage. Progress report, May 1, 1976--March 31, 1977. [Escherichia coli, gamma radiation, UV radiation]

Technical Report ·
DOI:https://doi.org/10.2172/7211823· OSTI ID:7211823
Last year's report that repair of DNA double-strand breaks from gamma rays occurs in E. coli was verified by additional experiments. Such repair requires recA function and the presence of another DNA molecule of the same base sequence, so it may involve a recombination-like event. Ultraviolet light acting on DNA containing bromouracil produces double-strand breaks by single photochemical events, and a single model can explain this as well as other results. Strains of E. coli which are unusually mutable by bromouracil--uvrE, mutL, mutR, mutS, are defective in mismatch repair. This strengthens the suggestion in last year's report that such mutagenesis occurs when enzymes responsible for the removal of mismatched bases are unable to remove all the mismatches. Ultraviolet mutagenesis of lambda phage may be a useful model for the study of mutagenesis in cells, because the effects of lesions in the gene mutated (i.e., in the phage) and changes in enzyme systems (by treating the host cells) can be examined separately. Quantitative data support this approach.
Research Organization:
Yale Univ., New Haven, Conn. (USA)
DOE Contract Number:
EY-76-S-02-3571
OSTI ID:
7211823
Report Number(s):
COO-3571-17
Country of Publication:
United States
Language:
English