Dataset Information

Budding yeast ATM/ATR contribute to meiotic double-strand-break (DSB) homeostasis by down-regulating Rec114, an essential component of the DSB-machinery

ABSTRACT: In most organisms, meiotic recombination begins with programmed DNA double strand break (DSB) formation by Spo11. Here, we present evidence that Tel1/Mec1, the budding yeast ATM/ATR, regulate DSB formation by phosphorylating Rec114, an essential Spo11-accessory protein. Analyses of a non-phosphorylatable- or phosphomimetic- alleles of rec114 revealed that DSB-dependent phosphorylation of Rec114 limited its association with DSB-hotspots resulting in reduction in DSB formation. Also observed were the impact of Rec114 phosphorylation on its homolog synapsis-associated removal from chromosomes and NDT80-dependent turnover. Specifically, we found that the synapsis- and NDT80-dependent Rec114 downregulation occurred later in the rec114 mutant with a reduced Spo11-catalysis, but earlier in the other with an enhanced catalysis, strongly implicating the existence of a feedback mechanism coupling the extent of Spo11-catalysis to Rec114 activity. Taken together, these observations suggest that three different mechanisms of down regulating Rec114 contribute to meiotic DSB homeostasis, a feedback mechanism to maintain the number of meiotic DSBs at the developmentally programmed level.

ORGANISM(S): Saccharomyces cerevisiae

PROVIDER: GSE43384 | GEO | 2013/06/01

SECONDARY ACCESSION(S): PRJNA185805

REPOSITORIES: GEO

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Project description:DNA double strand breaks (DSBs) in repetitive sequences are a potent source of genomic instability, due to the possibility of non-allelic homologous recombination (NAHR). Repetitive sequences are especially at risk during meiosis, when numerous programmed DSBs are introduced into the genome to initiate meiotic recombination 1. Within the budding yeast repetitive ribosomal (r)DNA array, meiotic DSB formation is prevented in part through Sir2-dependent heterochromatin 2,3. Here, we demonstrate that the edges of the rDNA array are exceptionally susceptible to meiotic DSBs, revealing an inherent heterogeneity within the rDNA array. We find that this localised DSB susceptibility necessitates a border-specific protection system consisting of the meiotic ATPase Pch2 and the origin recognition complex subunit Orc1. Upon disruption of these factors, DSB formation and recombination specifically increased in the outermost rDNA repeats, leading to NAHR and rDNA instability. Strikingly, the Sir2-dependent heterochromatin of the rDNA itself was responsible for the induction of DSBs at the rDNA borders in pch2? cells. Thus, while Sir2 activity globally prevents meiotic DSBs within the rDNA, it creates a highly permissive environment for DSB formation at the heterochromatin/euchromatin junctions. Heterochromatinised repetitive DNA arrays are abundantly present in most eukaryotic genomes. Our data define the borders of such chromatin domains as distinct high-risk regions for meiotic NAHR, whose protection may be a universal requirement to prevent meiotic genome rearrangements associated with genomic diseases and birth defects. This SuperSeries is composed of the following subset Series: GSE30071: ssDNA mapping in dmc1 strains GSE30072: ChIP-chip of DSB factors in wild type and pch2 strains Two types of study were undertaken to understand the regulation of meiotic DSB formation close to repetitive DNA elements in yeast. First, DSBs were mapped using ssDNA enrichment in strains isogenic for a dmc1 mutation, and also including pch2 delete, orc1-161, rdna delete and a reciprocal translocation between chromosomes 2 and 12 (trans2to12). Second, the association of the DSB factors Hop1, Rec114, Mer2, and Mre1, as well as total histone H3 and H3K4-trimethylation were measured by ChIP-chip analysis in wild-type and pch2 delete strains.