Article

Ajimura, M., Leem, S. H. & Ogawa, H. Identification of new genes required for meiotic recombination in Saccharomyces cerevisiae. Genetics 133, 51-66

Department of Biology, Faculty of Science, Osaka University, Japan.
Genetics (Impact Factor: 5.96). 02/1993; 133(1):51-66.
Source: PubMed
ABSTRACT
Mutants defective in meiotic recombination were isolated from a disomic haploid strain of Saccharomyces cerevisiae by examining recombination within the leu2 and his4 heteroalleles located on chromosome III. The mutants were classified into two new complementation groups (MRE2 and MRE11) and eight previously identified groups, which include SPO11, HOP1, REC114, MRE4/MEK1 and genes in the RAD52 epistasis group. All of the mutants, in which the mutations in the new complementation groups are homozygous and diploid, can undergo premeiotic DNA synthesis and produce spores. The spores are, however, not viable. The mre2 and mre11 mutants produce viable spores in a spo13 background, in which meiosis I is bypassed, suggesting that these mutants are blocked at an early step in meiotic recombination. The mre2 mutant does not exhibit any unusual phenotype during mitosis and it is, thus, considered to have a mutation in a meiosis-specific gene. By contrast, the mre11 mutant is sensitive to damage to DNA by methyl methanesulfonate and exhibits a hyperrecombination phenotype in mitosis. Among six alleles of HOP1 that were isolated, an unusual pattern of intragenic complementation was observed.

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    • "The MRE11-RAD50-NBS1 (MRN) complex (Figure 2) acts both as a sensor and an effector in the DDR, with crucial roles in the detection, signalling and repair of DSBs. Mre11 and Rad50 were originally characterized in genetic screens from Saccharomyces cerevisiae, the Mre11 mutant being defective in meiotic recombination [175] and Rad50 mutant sensitive to DNA damage [176]. NBS1 was later isolated as a member of the ternary complex, binding MRE11 and RAD50. "
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    • "Originally, Mre11 was identified in yeast, S. cerevisiae as a gene required for early steps of meiotic recombination, namely for induction as well as for repair of meiotic DSBs. Mutational analysis of the yeast MRE11 gene showed that its function in DSB initiation is located in the C-terminal part of the protein and is distinct from its end processing function which is associated with the N-terminal part of the protein [20,25,26]. Elucidating Mre11 function in vertebrates is hampered by the fact that null mutations in any component of the MRX complex cause embryonic lethality272829. "
    [Show abstract] [Hide abstract] ABSTRACT: The evolutionary conserved Mre11/Rad50/Nbs1 complex functions as one of the guardians of genome integrity in eukaryotes; it is required for the double-strand break repair, meiosis, DNA checkpoint, and telomere maintenance. To better understand the role of the MRE11 gene in Arabidopsis, we performed comparative analysis of several mre11 alleles with respect to genome stability and meiosis. The mre11-4 and mre11-2 alleles presumably produce truncated MRE11 proteins composed of the first 499 and 529 amino acids, respectively. Although the putative MRE11 truncated proteins differ only by 30 amino acids, the mutants exhibited strikingly different phenotypes in regards to growth morphology, genome stability and meiosis. While the mre11-2 mutants are fully fertile and undergo normal meiosis, the mre11-4 plants are sterile due to aberrant repair of meiotic DNA breaks. Structural homology analysis suggests that the T-DNA insertion in the mre11-4 allele probably disrupted the putative RAD50 interaction and/or homodimerization domain, which is assumed to be preserved in mre11-2 allele. Intriguingly, introgression of the atm-2 mutant plant into the mre11-2 background renders the double mutant infertile, a phenotype not observed in either parent line. This data indicate that MRE11 partially compensates for ATM deficiency in meiosis of Arabidopsis.
    Preview · Article · Oct 2013 · PLoS ONE
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    • "Originally, Mre11 was identified in yeast, S. cerevisiae as a gene required for early steps of meiotic recombination, namely for induction as well as for repair of meiotic DSBs. Mutational analysis of the yeast MRE11 gene showed that its function in DSB initiation is located in the C-terminal part of the protein and is distinct from its end processing function which is associated with the N-terminal part of the protein [20,25,26]. Elucidating Mre11 function in vertebrates is hampered by the fact that null mutations in any component of the MRX complex cause embryonic lethality272829. "
    [Show abstract] [Hide abstract] ABSTRACT: The evolutionary conserved Mre11/Rad50/Nbs1 complex functions as one of the guardians of genome integrity in eukaryotes; it is required for the double-strand break repair, meiosis, DNA checkpoint, and telomere maintenance. To better understand the role of the MRE11 gene in Arabidopsis, we performed comparative analysis of several mre11 alleles with respect to genome stability and meiosis. The mre11-4 and mre11-2 alleles presumably produce truncated MRE11 proteins composed of the first 499 and 529 amino acids, respectively. Although the putative MRE11 truncated proteins differ only by 30 amino acids, the mutants exhibited strikingly different phenotypes in regards to growth morphology, genome stability and meiosis. While the mre11-2 mutants are fully fertile and undergo normal meiosis, the mre11-4 plants are sterile due to aberrant repair of meiotic DNA breaks. Structural homology analysis suggests that the T-DNA insertion in the mre11-4 allele probably disrupted the putative RAD50 interaction and/or homodimerization domain, which is assumed to be preserved in mre11-2 allele. Intriguingly, introgression of the atm-2 mutant plant into the mre11-2 background renders the double mutant infertile, a phenotype not observed in either parent line. This data indicate that MRE11 partially compensates for ATM deficiency in meiosis of Arabidopsis. Citation: Šamanić I, Simunić J, Riha K, Puizina J (2013) Evidence for Distinct Functions of MRE11 in Arabidopsis Meiosis . PLoS ONE 8(10): e78760. doi: 10.1371/journal.pone.0078760
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