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FREQUENCY OF ULTRAVIOLET RADIATION‐INDUCED MUTATION AT THE hprt LOCUS IN REPAIR‐PROFICIENT MURINE FIBROBLASTS TRANSFECTED WITH THE denV GENE OF BACTERIOPHAGE T4
Author(s) -
Kusewitt Donna F.,
Budge Cindy L.,
Anderson Mary M.,
Ryan Sharon L.,
Ley Ronald D.
Publication year - 1993
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1993.tb09589.x
Subject(s) - transfection , mutant , microbiology and biotechnology , mutation frequency , biology , hypoxanthine guanine phosphoribosyltransferase , pyrimidine dimer , locus (genetics) , cell culture , gene , genetics , dna repair
— Thc frequency of spontaneous and ultraviolet radiation (UVR)‐induced mutation at the hprt locus was determined in control and denV‐transfected, repair‐proficient murine fibroblasts. Control cells removed an average of 25% of pyrimidine dimers induced by exposure to 150 J/m 2 UVR from an FS40 sunlamp within 24 h; under the same conditions of induction and repair, denV‐transfected cells removed an average of 71% of pyrimidine dimers. Control cells were somewhat more resistant than denV‐transfected cells to killing by UVR. The average frequency of spontancous mutation at the hprt locus for control and denV‐transfected cells was 3 and 15 6‐thioguanine (6‐TG)‐resistant colonies per 10 6 surviving cells, respectively; there was no statistically significant difference between control and dcnV‐transfected cells. However, after exposure to 75 or 150 J/m 2 UVR, denV‐transfected cells had a significantly lower frequency of mutation to 6‐TG resistance. After exposure to a fluence of 75 J/m 2 , the average frequency of UVR‐induced mutation at the hprt locus was 166 mutant colonies per lo h surviving cells for control cells and 92 mutant colonies for denV‐transfectcd cells; after 150 J/m 2 , control cells had 205 6‐TG‐resistant colonies per 10 6 cells, while dmV‐transfected cclls had 61 mutant colonies. These results demonstrate that UVR‐induced pyrimidine dimers are mutagenic photoproducts in mammalian cells.