The Number of Meiotic Double-Strand Breaks Influences Crossover Distribution in Arabidopsis.
Plant Cell
; 30(10): 2628-2638, 2018 10.
Article
em En
| MEDLINE
| ID: mdl-30282794
ABSTRACT
Meiotic recombination generates genetic diversity and ensures proper chromosome segregation. Recombination is initiated by the programmed formation of double-strand breaks (DSBs) in chromosomal DNA by DNA Topoisomerase VI-A Subunit (SPO11), a topoisomerase-like enzyme. Repair of some DSBs leads to the formation of crossovers (COs). In most organisms, including plants, the number of DSBs greatly exceeds the number of COs and which DSBs become CO sites is tightly controlled. The CO landscape is affected by DNA sequence and epigenome features of chromosomes as well as by global mechanisms controlling recombination dynamics. The latter are poorly understood and their effects on CO distribution are not well elucidated. To study how recombination dynamics affects CO distribution, we engineered Arabidopsis thaliana plants to carry hypomorphic alleles of SPO11-1 Two independent transgenic lines showed â¼30% and 40% reductions in DSB numbers, which were commensurate with the dosage of the SPO11-1 transcript. The reduction in DSB number resulted in proportional, although smaller, reductions of the number of COs. Most interestingly, CO distribution along the chromosomes was dramatically altered, with substantially fewer COs forming in pericentromeric chromosome regions. These results indicate that SPO11 activity, and the resulting DSB numbers are major factors shaping the CO landscape.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Arabidopsis
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Troca Genética
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Quebras de DNA de Cadeia Dupla
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Meiose
Idioma:
En
Revista:
Plant Cell
Assunto da revista:
BOTANICA
Ano de publicação:
2018
Tipo de documento:
Article
País de afiliação:
China