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Involvement of the Cohesin Cofactor PDS5 (SPO76) During Meiosis and DNA Repair in Arabidopsis thaliana.

Pradillo M, Knoll A, Oliver C, Varas J, Corredor E, Puchta H, Santos JL - Front Plant Sci (2015)

Bottom Line: Cohesin cofactors contribute to cohesin dynamics and interact with cohesin complexes during cell cycle.In Arabidopsis, AtWAPL proteins are essential during meiosis, however, the role of AtPDS5 remains to be ascertained.Furthermore, this cohesin cofactor could be important for the function of the AtSMC5/AtSMC6 complex.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Genética, Facultad de Biología, Universidad Complutense Madrid, Spain.

ABSTRACT
Maintenance and precise regulation of sister chromatid cohesion is essential for faithful chromosome segregation during mitosis and meiosis. Cohesin cofactors contribute to cohesin dynamics and interact with cohesin complexes during cell cycle. One of these, PDS5, also known as SPO76, is essential during mitosis and meiosis in several organisms and also plays a role in DNA repair. In yeast, the complex Wapl-Pds5 controls cohesion maintenance and colocalizes with cohesin complexes into chromosomes. In Arabidopsis, AtWAPL proteins are essential during meiosis, however, the role of AtPDS5 remains to be ascertained. Here we have isolated mutants for each of the five AtPDS5 genes (A-E) and obtained, after different crosses between them, double, triple, and even quadruple mutants (Atpds5a Atpds5b Atpds5c Atpds5e). Depletion of AtPDS5 proteins has a weak impact on meiosis, but leads to severe effects on development, fertility, somatic homologous recombination (HR) and DNA repair. Furthermore, this cohesin cofactor could be important for the function of the AtSMC5/AtSMC6 complex. Contrarily to its function in other species, our results suggest that AtPDS5 is dispensable during the meiotic division of Arabidopsis, although it plays an important role in DNA repair by HR.

No MeSH data available.


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AtPDS5 genes promote somatic homologous recombination. Quantification of somatic HR events in WT and Atpds5a Atpds5b Atpds5c plants containing the IC9 recombination reporter reveals a strongly significant reduction of HR frequency by about 50% in the triple mutant without (A) or with (B) treatment with 5 μg/ml bleomycin. Bars represent the mean number of recombination events per plant calculated from 4 replicates with 50 plants each. Error bars represent standard deviation. Statistical significance between WT and triple mutant was calculated using the Mann–Whitney test: ∗∗∗p < 0.001.
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Figure 6: AtPDS5 genes promote somatic homologous recombination. Quantification of somatic HR events in WT and Atpds5a Atpds5b Atpds5c plants containing the IC9 recombination reporter reveals a strongly significant reduction of HR frequency by about 50% in the triple mutant without (A) or with (B) treatment with 5 μg/ml bleomycin. Bars represent the mean number of recombination events per plant calculated from 4 replicates with 50 plants each. Error bars represent standard deviation. Statistical significance between WT and triple mutant was calculated using the Mann–Whitney test: ∗∗∗p < 0.001.

Mentions: Taking into account the DNA repair defects and the alterations in the expression of several genes involved in DNA damage response observed, we decided to analyze a possible effect on somatic HR. As the T-DNA in Atpds5e contains a GUS gene that might interfere with the reporter system that is based on the restoration of this gene by HR, we concentrated our effort on the triple mutant Atpds5a Atpds5b Atpds5c. We crossed it with the reporter line IC9 (Molinier et al., 2004). After isolation of the Atpds5a Atpds5b Atpds5c IC9 line, we determined the HR frequency with and without induction of DSBs by bleomycin. In untreated plants, the WT IC9 control showed about 0.8 recombination events per plant, while the HR frequency in the Atpds5a Atpds5b Atpds5c IC9 line was reduced by 50% to about 0.4 (Figure 6A; p < 0.001, n = 4, 50 plantlets each). Treatment with the DSB-inducing agent bleomycin induced the overall number of recombination events in both lines by a factor of 27. However, the Atpds5a Atpds5b Atpds5c IC9 line still displayed a HR frequency that was only about 50% of the WT IC9 control line (Figure 6B; p < 0.001, n = 4, 50 plantlets each). Thus, HR efficiency is indeed reduced in the mutant background.


Involvement of the Cohesin Cofactor PDS5 (SPO76) During Meiosis and DNA Repair in Arabidopsis thaliana.

Pradillo M, Knoll A, Oliver C, Varas J, Corredor E, Puchta H, Santos JL - Front Plant Sci (2015)

AtPDS5 genes promote somatic homologous recombination. Quantification of somatic HR events in WT and Atpds5a Atpds5b Atpds5c plants containing the IC9 recombination reporter reveals a strongly significant reduction of HR frequency by about 50% in the triple mutant without (A) or with (B) treatment with 5 μg/ml bleomycin. Bars represent the mean number of recombination events per plant calculated from 4 replicates with 50 plants each. Error bars represent standard deviation. Statistical significance between WT and triple mutant was calculated using the Mann–Whitney test: ∗∗∗p < 0.001.
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Figure 6: AtPDS5 genes promote somatic homologous recombination. Quantification of somatic HR events in WT and Atpds5a Atpds5b Atpds5c plants containing the IC9 recombination reporter reveals a strongly significant reduction of HR frequency by about 50% in the triple mutant without (A) or with (B) treatment with 5 μg/ml bleomycin. Bars represent the mean number of recombination events per plant calculated from 4 replicates with 50 plants each. Error bars represent standard deviation. Statistical significance between WT and triple mutant was calculated using the Mann–Whitney test: ∗∗∗p < 0.001.
Mentions: Taking into account the DNA repair defects and the alterations in the expression of several genes involved in DNA damage response observed, we decided to analyze a possible effect on somatic HR. As the T-DNA in Atpds5e contains a GUS gene that might interfere with the reporter system that is based on the restoration of this gene by HR, we concentrated our effort on the triple mutant Atpds5a Atpds5b Atpds5c. We crossed it with the reporter line IC9 (Molinier et al., 2004). After isolation of the Atpds5a Atpds5b Atpds5c IC9 line, we determined the HR frequency with and without induction of DSBs by bleomycin. In untreated plants, the WT IC9 control showed about 0.8 recombination events per plant, while the HR frequency in the Atpds5a Atpds5b Atpds5c IC9 line was reduced by 50% to about 0.4 (Figure 6A; p < 0.001, n = 4, 50 plantlets each). Treatment with the DSB-inducing agent bleomycin induced the overall number of recombination events in both lines by a factor of 27. However, the Atpds5a Atpds5b Atpds5c IC9 line still displayed a HR frequency that was only about 50% of the WT IC9 control line (Figure 6B; p < 0.001, n = 4, 50 plantlets each). Thus, HR efficiency is indeed reduced in the mutant background.

Bottom Line: Cohesin cofactors contribute to cohesin dynamics and interact with cohesin complexes during cell cycle.In Arabidopsis, AtWAPL proteins are essential during meiosis, however, the role of AtPDS5 remains to be ascertained.Furthermore, this cohesin cofactor could be important for the function of the AtSMC5/AtSMC6 complex.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Genética, Facultad de Biología, Universidad Complutense Madrid, Spain.

ABSTRACT
Maintenance and precise regulation of sister chromatid cohesion is essential for faithful chromosome segregation during mitosis and meiosis. Cohesin cofactors contribute to cohesin dynamics and interact with cohesin complexes during cell cycle. One of these, PDS5, also known as SPO76, is essential during mitosis and meiosis in several organisms and also plays a role in DNA repair. In yeast, the complex Wapl-Pds5 controls cohesion maintenance and colocalizes with cohesin complexes into chromosomes. In Arabidopsis, AtWAPL proteins are essential during meiosis, however, the role of AtPDS5 remains to be ascertained. Here we have isolated mutants for each of the five AtPDS5 genes (A-E) and obtained, after different crosses between them, double, triple, and even quadruple mutants (Atpds5a Atpds5b Atpds5c Atpds5e). Depletion of AtPDS5 proteins has a weak impact on meiosis, but leads to severe effects on development, fertility, somatic homologous recombination (HR) and DNA repair. Furthermore, this cohesin cofactor could be important for the function of the AtSMC5/AtSMC6 complex. Contrarily to its function in other species, our results suggest that AtPDS5 is dispensable during the meiotic division of Arabidopsis, although it plays an important role in DNA repair by HR.

No MeSH data available.


Related in: MedlinePlus