Cloning and characterisation of theSchizosaccharomyces pombe rad32gene: a gene required for repair of double strand breaks and recombination

Abstract

A new Schizosaccharomyces pombe mutant (rad32) which is sensitive to gamma and UV irradiation is described. Pulsed field gel electrophoresis of DNA from irradiated cells indicates that the rad32 mutant, in comparison to wild type cells, has decreased ability to repair DNA double strand breaks. The mutant also undergoes decreased meiotic recombination and displays reduced stability of minichromosomes. The rad32 gene has been cloned by complementation of the UV sensitive phenotype. The gene, which is not essential for cell viability and is expressed at a moderate level in mitotically dividing cells, has significant homology to the meiotic recombination gene MRE11 of Saccharomyces cerevisiae. Epistasis analysis indicates that rad32 functions in a pathway which includes the rhp51 gene (the S.pombe homologue to S.cerevisiae RAD51) and that cells deleted for the rad32 gene in conjunction with either the rad3 deletion (a G2 checkpoint mutation) or the rad2 deletion (a chromosome stability and potential nucleotide excision repair mutation) are not viable.

Linear Element-Independent Meiotic Recombination in Schizosaccharomyces pombe

“…Moreover, while the rec10-155 mutant is defective in recombination, we cannot dismiss the possibility that LinEs have no function in regulating interhomolog meiotic recombination to any degree and that the reduced recombination levels observed in this allele are 29.1 6 9.2 1.0 6 0.4 rec10-175 37.5 6 10.4 14.4 6 3.0 a n $ 4 in all cases; values are 6 SD. b Similar to values previously reported for the rad32D mutant (Tavassoli et al 1995). p caused by other functions of Rec10 being impaired due to the truncation of the Rec10 protein and not due to the loss of LinEs per se.…”

“…Rad32 is required to process recombination-initiating lesions. If such lesions are formed in the absence of Rad32 they cannot be properly processed and there is a low viable spore yield (Tavassoli et al 1995). However, if no initiating lesions form then the viable spore yield is elevated to levels consistent with random segregation of the three S. pombe chromosomes, i.e., $12% (see Ellermeier and Smith 2005 for further details).…”

Inactivation of Mre11 Does Not Affect VSG Gene Duplication Mediated by Homologous Recombination in Trypanosoma brucei

“…Usually, inactivation of Mre11 leads to increased sensitivity to MMS (3,7,20,22,53), although this is not always the case when the NBS1 component of the human M/R complex is mutated (54). Nonetheless, the sensitivity of the trypanosome null mutant to phleomycin and its altered integration patterns do show that Mre11 is involved in repair and recombination.…”

Exo1 Roles for Repair of DNA Double-Strand Breaks and Meiotic Crossing Over inSaccharomyces cerevisiae

“…MMS, a radiomimetic agent, is assumed to cause DSBs, and the MMS sensitivity of the mre11 mutant is attributed to its inability to repair DSBs (Tavassoli et al, 1995;Bressan et al, 1998). DSBs are predominantly repaired by homologous recombination in yeast (Friedberg et al, 1995), and the process of mating-type switching serves as a model system for analyzing the recombination process (Haber, 1995).…”