UV irradiation causes the loss of viable mitotic recombinants in Schizosaccharomyces pombe cells lacking the G(2)/M DNA damage checkpoint.
891 - 908.
Elevated mitotic recombination and cell cycle delays are MO Of the cellular responses to LTV induced DNA damage. Cell cycle delays in response to DNA damage are mediated via checkpoint proteins, Two distinct DNA damage checkpoints have been characterized in Schizosaccharomyces pombe: an intra-S-phase checkpoint slows replication and a G(g)/M checkpoint stops cells passing from G, into mitosis. In this study we have sought to determine whether UV damage-induced mitotic intrachromosomal recombination relies on damage-induced cell cycle delays. The spontaneous and UV-induced recombination phenotypes were determined for checkpoint mutants lacking the intra-S and/or the G(2)/M checkpoint. Spontaneous mitotic recombinants arc thought to arise due to endogenous DNA damage and/or intrinsic stalling OF replication forks. Cells lacking only the intra-S checkpoint exhibited no UV-induced increase in the frequency of recombinants above spontaneous levels. Mutants lacking the G(2)/M checkpoint exhibited a novel phenotype; following UV irradiation the recombinant frequency fell below the frequency of spontaneous recombinants. This implies that, as well as UV-induced recombinants, spontaneous recombinants are also lost in G(2)/M mutants after UV irradiation. Therefore, as well as lack of time for DNA repair, loss of spontaneous and damage-induced recombinants also contributes to cell death in UV-irradiated G(2)/M checkpoint mutants.
|Title:||UV irradiation causes the loss of viable mitotic recombinants in Schizosaccharomyces pombe cells lacking the G(2)/M DNA damage checkpoint|
|Keywords:||SISTER-CHROMATID RECOMBINATION, BREAK-INDUCED RECOMBINATION, FISSION YEAST, SACCHAROMYCES-CEREVISIAE, HOMOLOGOUS RECOMBINATION, GENETIC-CONTROL, INTRACHROMOSOMAL RECOMBINATION, CYCLE CHECKPOINTS, PROTEIN-KINASE, RAD51 HOMOLOG|
|UCL classification:||UCL > School of Life and Medical Sciences > Faculty of Life Sciences > Biosciences (Division of) > Structural and Molecular Biology|
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