title: DNA mismatch repair mediates protection from mutagenesis induced by short-wave ultraviolet light.
abstract: To investigate involvement of DNA mismatch repair in the response to short-wave ultraviolet (UVC) light, we compared UVC-induced mutant frequencies and mutational spectra at the Hprt gene between wild type and mismatch-repair-deficient mouse embryonic stem (ES) cells. Whereas mismatch repair gene status did not significantly affect survival of these cells after UVC irradiation, UVC induced substantially more mutations in ES cells that lack the MutSalpha mismatch-recognizing heterodimer than in wild type ES cells. The global UVC-induced mutational spectra at Hprt and the distribution of most spectral mutational hotspots were found to be similar in mismatch-repair-deficient and wild type cells. However, at one predominant spectral hot spot for mutagenesis in wild type cells, the UVC-induced mutation frequency was not affected by the mismatch repair status. Together these data reveal a major role of mismatch repair in controlling mutagenesis induced by UVC light and may suggest the sequence context-dependent direct mismatch repair of misincorporations opposite UVC-induced pyrimidine dimers.
authors.affiliation: Department of Toxicogenetics, Leiden University Medical Center, PO Box 9600, 2300 RC Leiden, The Netherlands.
authors.forename: Viola
authors.initials: V
authors.lastname: Borgdorff
authors.forename: Bea
authors.initials: B
authors.lastname: Pauw
authors.forename: Sandrine
authors.initials: S
authors.lastname: van Hees-Stuivenberg
authors.forename: Niels
authors.initials: N
authors.lastname: de Wind
mesh_terms: D000818:Animals; D017209:Apoptosis; D002460:Cell Line; D053843:DNA Mismatch Repair; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D053595:Embryonic Stem Cells / Q000528:radiation effects; D007041:Hypoxanthine Phosphoribosyltransferase / Q000235:genetics; D051379:Mice; D008957:Models, Genetic; D051718:MutS Homolog 2 Protein / Q000235:genetics / Q000378:metabolism; D016296:Mutagenesis; D017354:Point Mutation; D014466:Ultraviolet Rays
chemical_list: D004268:DNA-Binding Proteins; C102997:Msh6 protein, mouse; D007041:Hypoxanthine Phosphoribosyltransferase; C497173:Msh2 protein, mouse; D051718:MutS Homolog 2 Protein