TY - JOUR
T1 - The STRUCTURAL MAINTENANCE of CHROMOSOMES 5/6 complex promotes sister chromatid alignment and homologous recombination after DNA damage in Arabidopsis thaliana
AU - Watanabe, Koichi
AU - Pacher, Michael
AU - Dukowic, Stefanie
AU - Schubert, Veit
AU - Puchta, Holger
AU - Schubert, Ingo
PY - 2009
Y1 - 2009
N2 - Sister chromatids are often arranged as incompletely aligned entities in interphase nuclei of Arabidopsis thaliana. The STRUCTURAL MAINTENANCE OF CHROMOSOMES (SMC) 5/6 complex, together with cohesin, is involved in double-strand break (DSB) repair by sister chromatid recombination in yeasts and mammals. Here, we analyzed the function of genes in Arabidopsis. The wild-type allele of SMC5 is essential for seed development. Each of the two SMC6 homologs of Arabidopsis is required for efficient repair of DNA breakage via intermolecular homologous recombination in somatic cells. Alignment of sister chromatids is enhanced transiently after X-irradiation (and mitomycin C treatment) in wild-type nuclei. In the smc5/6 mutants, the x-ray-mediated increase in sister chromatid alignment is much lower and delayed. The reduced S phase-established cohesion caused by a knockout mutation in one of the α-kleisin genes, SYN1, also perturbed enhancement of sister chromatid alignment after irradiation, suggesting that the S phase-established cohesion is a prerequisite for correct DSB-dependent cohesion. The radiation-sensitive51 mutant, deficient in heteroduplex formation during DSB repair, showed wild-type frequencies of sister chromatid alignment after X-irradiation, implying that the irradiation-mediated increase in sister chromatid alignment is a prerequisite for, rather than a consequence of, DNA strand exchange between sister chromatids. Our results suggest that the SMC5/6 complex promotes sister chromatid cohesion after DNA breakage and facilitates homologous recombination between sister chromatids.
AB - Sister chromatids are often arranged as incompletely aligned entities in interphase nuclei of Arabidopsis thaliana. The STRUCTURAL MAINTENANCE OF CHROMOSOMES (SMC) 5/6 complex, together with cohesin, is involved in double-strand break (DSB) repair by sister chromatid recombination in yeasts and mammals. Here, we analyzed the function of genes in Arabidopsis. The wild-type allele of SMC5 is essential for seed development. Each of the two SMC6 homologs of Arabidopsis is required for efficient repair of DNA breakage via intermolecular homologous recombination in somatic cells. Alignment of sister chromatids is enhanced transiently after X-irradiation (and mitomycin C treatment) in wild-type nuclei. In the smc5/6 mutants, the x-ray-mediated increase in sister chromatid alignment is much lower and delayed. The reduced S phase-established cohesion caused by a knockout mutation in one of the α-kleisin genes, SYN1, also perturbed enhancement of sister chromatid alignment after irradiation, suggesting that the S phase-established cohesion is a prerequisite for correct DSB-dependent cohesion. The radiation-sensitive51 mutant, deficient in heteroduplex formation during DSB repair, showed wild-type frequencies of sister chromatid alignment after X-irradiation, implying that the irradiation-mediated increase in sister chromatid alignment is a prerequisite for, rather than a consequence of, DNA strand exchange between sister chromatids. Our results suggest that the SMC5/6 complex promotes sister chromatid cohesion after DNA breakage and facilitates homologous recombination between sister chromatids.
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U2 - 10.1105/tpc.108.060525
DO - 10.1105/tpc.108.060525
M3 - Article
C2 - 19737979
AN - SCOPUS:70849109889
SN - 1040-4651
VL - 21
SP - 2688
EP - 2699
JO - Plant Cell
JF - Plant Cell
IS - 9
ER -