Loss of DNA methylation affects the recombination landscape in Arabidopsis

Article Article scientifique Article Loss of DNA methylation affects the recombination landscape in Arabidopsis eng 2012 author Mirouze Marie 646829 author Lieberman Lazarovich Michal 733150 author Aversano Riccardo 689558 author Bucher Etienne 651582 author Nicolet Joël 114592 author Reinders Jon 585979 author Paszkowski Jerzy 134849 5880-5885 10.1073/pnas.1120841109 22451936 0027-8424 http://www.pnas.org/content/109/15/5880.long During sexual reproduction, one-half of the genetic material is deposited in gametes, and a complete set of chromosomes is restored upon fertilization. Reduction of the genetic information before gametogenesis occurs in meiosis, when cross-overs (COs) between homologous chromosomes secure an exchange of their genetic information. COs are not evenly distributed along chromosomes and are suppressed in chromosomal regions encompassing compact, hypermethylated centromeric and pericentromeric DNA. Therefore, it was postulated that DNA hypermethylation is inhibitory to COs. Here, when analyzing meiotic recombination in mutant plants with hypomethylated DNA, we observed unexpected and counterintuitive effects of DNA methylation losses on CO distribution. Recombination was further promoted in the hypomethylated chromosome arms while it was inhibited in heterochromatic regions encompassing pericentromeric DNA. Importantly, the total number of COs was not affected, implying that loss of DNA methylation led to a global redistribution of COs along chromosomes. To determine by which mechanisms altered levels of DNA methylation influence recombination--whether directly in cis or indirectly in trans by changing expression of genes encoding recombination components--we analyzed CO distribution in wild-type lines with randomly scattered and well-mapped hypomethylated chromosomal segments. The results of these experiments, supported by expression profiling data, suggest that DNA methylation affects meiotic recombination in cis. Because DNA methylation exhibits significant variation even within a single species, our results imply that it may influence the evolution of plant genomes through the control of meiotic recombination. Arabidopsis/cytology/genetics Arabidopsis Proteins/genetics Chromosomes, Plant/genetics DNA (Cytosine-5-)-Methyltransferase/genetics DNA Methylation/genetics Euchromatin/metabolism Heterochromatin/metabolism Inbreeding Meiosis/genetics Mutation/genetics Recombination, Genetic Dewey 580 45 Département des sciences végétales 163 false Proceedings of the National Academy of Sciences of the United States of America 109 15 12df7a69-6974-4294-bc31-dd8cfeecd3ab Article (Published version) Restricted Mirouze_PNAS_2012.pdf 1117014 application/pdf restrictedAccess Faculté des sciences / Section de biologie / Département des sciences végétales

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Loss of DNA methylation affects the recombination landscape in Arabidopsis	Proceedings of the National Academy of Sciences of the United States of America			2012	577	0

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Aversano, Riccardo