title: The use of a yeast strain with a temperature-sensitive DNA ligase to estimate DNA repair after exposure to mutagens.
abstract: The yeast strain cdc9 which possesses a temperature-sensitive DNA ligase, was used to estimate DNA repair after mutagen exposure. Following low UV fluences, single-strand breaks in DNA were detected after an incubation at the restrictive temperature but were absent at the permissive temperature. These DNA breaks were shown to be equal to the number of pyrimidine dimers induced in DNA as measured by the presence of UV-endonuclease sensitive sites. Similarly, after exposure to the chemical mutagen 4-chloromethyl-biphenyl (4CMB) single-strand breaks accumulated at the restrictive temperature. Hence the technique described should be applicable for the estimation of the early steps of repair of a wide range of different types of DNA damage induced in yeast by exposure to either physical or chemical mutagens.
mesh_terms: D011088:DNA Ligases / Q000378:metabolism*; D004260:DNA Repair; D004271:DNA, Fungal / Q000528:radiation effects; D005821:Genetic Techniques; D008433:Mathematics; D011118:Polynucleotide Ligases / Q000378:metabolism*; D011740:Pyrimidine Dimers; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D014466:Ultraviolet Rays
chemical_list: D004271:DNA, Fungal; D011740:Pyrimidine Dimers; D011088:DNA Ligases; D011118:Polynucleotide Ligases