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The role of AtMUS81 in interference-insensitive crossovers in A. thaliana.

Berchowitz LE, Francis KE, Bey AL, Copenhaver GP - PLoS Genet. (2007)

Bottom Line: The AtMUS81 transcript is produced in all tissues, but is elevated greater than 9-fold in the anthers and its levels are increased in response to gamma radiation and methyl methanesulfonate treatment.Data from genetic intervals on Chromosomes 1 and 3 show that Atmus81 mutants have a moderate decrease in meiotic recombination.These data are consistent with the hypothesis that AtMUS81 is involved in a secondary subset of meiotic crossovers that are interference insensitive.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America.

ABSTRACT
MUS81 is conserved among plants, animals, and fungi and is known to be involved in mitotic DNA damage repair and meiotic recombination. Here we present a functional characterization of the Arabidopsis thaliana homolog AtMUS81, which has a role in both mitotic and meiotic cells. The AtMUS81 transcript is produced in all tissues, but is elevated greater than 9-fold in the anthers and its levels are increased in response to gamma radiation and methyl methanesulfonate treatment. An Atmus81 transfer-DNA insertion mutant shows increased sensitivity to a wide range of DNA-damaging agents, confirming its role in mitotically proliferating cells. To examine its role in meiosis, we employed a pollen tetrad-based visual assay. Data from genetic intervals on Chromosomes 1 and 3 show that Atmus81 mutants have a moderate decrease in meiotic recombination. Importantly, measurements of recombination in a pair of adjacent intervals on Chromosome 5 demonstrate that the remaining crossovers in Atmus81 are interference sensitive, and that interference levels in the Atmus81 mutant are significantly greater than those in wild type. These data are consistent with the hypothesis that AtMUS81 is involved in a secondary subset of meiotic crossovers that are interference insensitive.

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Hypersensitivity of Atmus81 Mutants to MMS, Cisplatin, and Gamma Radiation(A) Wild-type Col-0 (rows one and three) and mutant Atmus81/Atmus81 (rows two and four) were subjected to a gradient (0–75 ppm) of MMS. The photograph was taken after 20 d. The wild-type plants can grow at each concentration tested while the mutants cannot grow at >30 ppm MMS. (B) Wild-type Col-0 (right side of plate) and mutant Atmus81/Atmus81 (left side of plate) were subjected to various concentrations of cisplatin (0–15 ppm). The photograph was taken after 12 d. Wild-type plants consistently outperformed the mutants at all concentrations tested.(C) Wild-type Col-0 (upper left third), mutant Atmus81/Atmus81 (upper right third), and gamma-hypersensitive mutant atm-2/atm-2 (bottom third) were exposed to various levels of gamma radiation (0–150 Gy). At 75–100 Gy, the Atmus81 mutants resembled the atm-2 mutants rather than the wild-type plants.
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pgen-0030132-g002: Hypersensitivity of Atmus81 Mutants to MMS, Cisplatin, and Gamma Radiation(A) Wild-type Col-0 (rows one and three) and mutant Atmus81/Atmus81 (rows two and four) were subjected to a gradient (0–75 ppm) of MMS. The photograph was taken after 20 d. The wild-type plants can grow at each concentration tested while the mutants cannot grow at >30 ppm MMS. (B) Wild-type Col-0 (right side of plate) and mutant Atmus81/Atmus81 (left side of plate) were subjected to various concentrations of cisplatin (0–15 ppm). The photograph was taken after 12 d. Wild-type plants consistently outperformed the mutants at all concentrations tested.(C) Wild-type Col-0 (upper left third), mutant Atmus81/Atmus81 (upper right third), and gamma-hypersensitive mutant atm-2/atm-2 (bottom third) were exposed to various levels of gamma radiation (0–150 Gy). At 75–100 Gy, the Atmus81 mutants resembled the atm-2 mutants rather than the wild-type plants.

Mentions: A feature of mus81 mutants in other organisms is that they exhibit increased sensitivity to many DNA-damaging agents [19,21,29]. To determine if the Atmus81 insertion mutant has elevated sensitivity to DNA damage, we exposed seedlings to the radiomimetic MMS. We assayed the growth of both mutant and wild-type individuals (six replicates) on a gradient of MMS concentrations from 0 to 75 ppm (Figure 2A). Visual analysis showed that although both wild-type and homozygous mutants became more sickly with increased concentration of MMS, the Atmus81 mutants consistently died at 40 ppm while the wild type lines were much healthier at this concentration and survived at even the highest dosages we tested. These results are consistent with those reported by Hartung et al. [27].


The role of AtMUS81 in interference-insensitive crossovers in A. thaliana.

Berchowitz LE, Francis KE, Bey AL, Copenhaver GP - PLoS Genet. (2007)

Hypersensitivity of Atmus81 Mutants to MMS, Cisplatin, and Gamma Radiation(A) Wild-type Col-0 (rows one and three) and mutant Atmus81/Atmus81 (rows two and four) were subjected to a gradient (0–75 ppm) of MMS. The photograph was taken after 20 d. The wild-type plants can grow at each concentration tested while the mutants cannot grow at >30 ppm MMS. (B) Wild-type Col-0 (right side of plate) and mutant Atmus81/Atmus81 (left side of plate) were subjected to various concentrations of cisplatin (0–15 ppm). The photograph was taken after 12 d. Wild-type plants consistently outperformed the mutants at all concentrations tested.(C) Wild-type Col-0 (upper left third), mutant Atmus81/Atmus81 (upper right third), and gamma-hypersensitive mutant atm-2/atm-2 (bottom third) were exposed to various levels of gamma radiation (0–150 Gy). At 75–100 Gy, the Atmus81 mutants resembled the atm-2 mutants rather than the wild-type plants.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC1941751&req=5

pgen-0030132-g002: Hypersensitivity of Atmus81 Mutants to MMS, Cisplatin, and Gamma Radiation(A) Wild-type Col-0 (rows one and three) and mutant Atmus81/Atmus81 (rows two and four) were subjected to a gradient (0–75 ppm) of MMS. The photograph was taken after 20 d. The wild-type plants can grow at each concentration tested while the mutants cannot grow at >30 ppm MMS. (B) Wild-type Col-0 (right side of plate) and mutant Atmus81/Atmus81 (left side of plate) were subjected to various concentrations of cisplatin (0–15 ppm). The photograph was taken after 12 d. Wild-type plants consistently outperformed the mutants at all concentrations tested.(C) Wild-type Col-0 (upper left third), mutant Atmus81/Atmus81 (upper right third), and gamma-hypersensitive mutant atm-2/atm-2 (bottom third) were exposed to various levels of gamma radiation (0–150 Gy). At 75–100 Gy, the Atmus81 mutants resembled the atm-2 mutants rather than the wild-type plants.
Mentions: A feature of mus81 mutants in other organisms is that they exhibit increased sensitivity to many DNA-damaging agents [19,21,29]. To determine if the Atmus81 insertion mutant has elevated sensitivity to DNA damage, we exposed seedlings to the radiomimetic MMS. We assayed the growth of both mutant and wild-type individuals (six replicates) on a gradient of MMS concentrations from 0 to 75 ppm (Figure 2A). Visual analysis showed that although both wild-type and homozygous mutants became more sickly with increased concentration of MMS, the Atmus81 mutants consistently died at 40 ppm while the wild type lines were much healthier at this concentration and survived at even the highest dosages we tested. These results are consistent with those reported by Hartung et al. [27].

Bottom Line: The AtMUS81 transcript is produced in all tissues, but is elevated greater than 9-fold in the anthers and its levels are increased in response to gamma radiation and methyl methanesulfonate treatment.Data from genetic intervals on Chromosomes 1 and 3 show that Atmus81 mutants have a moderate decrease in meiotic recombination.These data are consistent with the hypothesis that AtMUS81 is involved in a secondary subset of meiotic crossovers that are interference insensitive.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America.

ABSTRACT
MUS81 is conserved among plants, animals, and fungi and is known to be involved in mitotic DNA damage repair and meiotic recombination. Here we present a functional characterization of the Arabidopsis thaliana homolog AtMUS81, which has a role in both mitotic and meiotic cells. The AtMUS81 transcript is produced in all tissues, but is elevated greater than 9-fold in the anthers and its levels are increased in response to gamma radiation and methyl methanesulfonate treatment. An Atmus81 transfer-DNA insertion mutant shows increased sensitivity to a wide range of DNA-damaging agents, confirming its role in mitotically proliferating cells. To examine its role in meiosis, we employed a pollen tetrad-based visual assay. Data from genetic intervals on Chromosomes 1 and 3 show that Atmus81 mutants have a moderate decrease in meiotic recombination. Importantly, measurements of recombination in a pair of adjacent intervals on Chromosome 5 demonstrate that the remaining crossovers in Atmus81 are interference sensitive, and that interference levels in the Atmus81 mutant are significantly greater than those in wild type. These data are consistent with the hypothesis that AtMUS81 is involved in a secondary subset of meiotic crossovers that are interference insensitive.

Show MeSH
Related in: MedlinePlus