EXO1 promotes the meiotic MLH1-MLH3 endonuclease through conserved interactions with MLH1, MSH4 and DNA
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ABSTRACT:
PROVIDER: PRJEB88381 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| ERR14838039.fastq.gz | Fastqsanger.gz | |||
| ERR14838040.fastq.gz | Fastqsanger.gz |
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Project description:Programmed DNA double-strand breaks (DSBs) initiate meiotic recombination and their subsequent repair culminates in crossover (CO) formation. COs result from the asymmetric cleavage of double-Holliday junction (dHJ) intermediates, that requires the MutLγ endonuclease and a non-catalytic function of Exo1, an activity essential for fertility but at risk of generating unwanted chromosome rearrangements. Here we show how crossover formation by MutLγ is activated at the right time and at the right place. MutLγ forms a constitutive complex with Exo1, and in meiotic cells transiently contacts the upstream MutSγ (Msh4-Msh5) heterodimer. MutLγ associates with DSB hotspots only once recombination intermediates have been stabilized and engaged in the crossover repair pathway. MutLγ-Exo1 is recruited to DSB hotspots independently of the polo-like Cdc5 kinase, but to activate dHJ resolution, Cdc5 is recruited to the recombination intermediates and interacts individually with both MutLγ and Exo1, suggesting their direct modification. in vivo, MutLγ occupancy is restrained on recombination intermediates, and MutLγ associates with the vast majority of DSB hotspots, but at a lower frequency in centromeres, consistent with a strategy to reduce at-risk crossover events in these regions, and in late replicating regions. Our data highlight the tight temporal and spatial control of the activity of this constitutive, potentially harmful, nuclease.
2020-01-15 | GSE133108 | GEO
Project description:Programmed DNA double-strand breaks (DSBs) initiate meiotic recombination and their subsequent repair culminates in crossover (CO) formation. COs result from the asymmetric cleavage of double-Holliday junction (dHJ) intermediates, that requires the MutLγ complex together with a non-catalytic function of Exo1, an activity essential for fertility but at risk of generating unwanted chromosome rearrangements. Here we show how crossover formation by MutLγ is activated at the right time and at the right place. MutLγ forms a constitutive complex with Exo1, and in meiotic cells transiently contacts the upstream MutSγ (Msh4-Msh5) heterodimer. MutLγ associates with DSB hotspots at a late step in the recombinational repair, once recombination intermediates have been stabilized and engaged in the crossover repair pathway. MutLγ-Exo1 is recruited to DSB hotspots independently of the polo-like Cdc5 kinase, but to activate dHJ resolution, Cdc5 is recruited to the recombination intermediates and interacts individually with both MutLγ and Exo1, suggesting their direct modification. in vivo, MutLγ occupancy is restrained on recombination intermediates, and genome-wide, MutLγ associates with the vast majority of DSB hotspots, but at a lower frequency in centromeres, consistent with a strategy to reduce at-risk crossover events in these regions, and in late replicating regions. Our data highlight the highly temporally and spatially control of the activity of this constitutive, potentially harmful, nuclease
2019-12-01 | GSE132850 | GEO
Project description:Homologous recombination is essential for high-fidelity DNA repair during mitotic proliferation and meiosis. Yet, context-specific modifications must tailor the recombination machinery to avoid, or enforce, formation of reciprocal exchanges – crossovers – between recombining chromosomes. To obtain molecular insight into how crossover control is achieved, we affinity-purified the 7 DNA-processing enzymes with known roles in channelling HR intermediates into crossovers, or non-crossovers, from vegetative cells, or cells undergoing meiosis. Using mass spectrometry, we provide the first global characterization of their composition. The resulting mitosis- and meiosis-specific interaction maps reveal intricate changes in enzyme architecture and a concerted rewiring of the interaction networks to support flexible control to the recombination outcome. Moreover, functional analyses of 31 novel interactions uncovered 8 meiosis-specific network components that remodel HR to support crossing-over. Chd1, which transiently associates with Exo1 during meiosis, enables the formation of MutLγ-Exo1-dependent crossovers through its conserved ability to bind and displace nucleosomes.
2019-07-31 | PXD012486 | Pride
Project description:Drosophila melanogaster Mlh1, Mlh1, is differentially expressed in 18 experiment(s);
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Project description:Drosophila melanogaster Mlh1, Mlh1, is expressed in 2 baseline experiment(s);
| FBgn0011659 | ExpressionAtlas
Project description:Background: Constitutional MLH1 epimutations are characterized by monoallelic methylation of the MLH1 promoter throughout normal tissues, accompanied by allele-specific silencing. The mechanism underlying primary MLH1 epimutations is currently unknown. The aim of this study was to perform an in-depth characterization of constitutional MLH1 epimutations targeting the aberrantly methylated region around MLH1 and other genomic loci. Methods: Twelve MLH1 epimutation carriers, 61 Lynch syndrome patients and 41 healthy controls, were analyzed by Infinium Human Methylation 450K beadchip, and targeted molecular techniques were used to characterize the MLH1 epimutation in carriers and their inheritance pattern. Results: No nucleotide or structural variants were identified in-cis on the epimutated allele in ten carriers, in which intergenerational methylation erasure was demonstrated in two, suggesting primary type of epimutation. CNVs outside the MLH1 locus were found in two cases. EPM2AIP1-MLH1 CpG island was identified as the sole differentially methylated region in MLH1 epimutation carriers compared to controls. Conclusion: Primary constitutional MLH1 epimutations arise as a focal epigenetic event at the EPM2AIP1-MLH1 CpG island in the absence of cis-acting genetic variants. Further molecular characterization is needed to elucidate the mechanistic basis of MLH1 epimutations and their heritability/reversibility.
2017-11-28 | GSE107351 | GEO
Project description:Background: Constitutional MLH1 epimutations are characterized by monoallelic methylation of the MLH1 promoter throughout normal tissues, accompanied by allele-specific silencing. The mechanism underlying primary MLH1 epimutations is currently unknown. The aim of this study was to perform an in-depth characterization of constitutional MLH1 epimutations targeting the aberrantly methylated region around MLH1 and other genomic loci. Methods: Twelve MLH1 epimutation carriers, 61 Lynch syndrome patients and 41 healthy controls, were analyzed by Infinium Human Methylation 450K beadchip, and targeted molecular techniques were used to characterize the MLH1 epimutation in carriers and their inheritance pattern. Results: No nucleotide or structural variants were identified in-cis on the epimutated allele in ten carriers, in which intergenerational methylation erasure was demonstrated in two, suggesting primary type of epimutation. CNVs outside the MLH1 locus were found in two cases. EPM2AIP1-MLH1 CpG island was identified as the sole differentially methylated region in MLH1 epimutation carriers compared to controls. Conclusion: Primary constitutional MLH1 epimutations arise as a focal epigenetic event at the EPM2AIP1-MLH1 CpG island in the absence of cis-acting genetic variants. Further molecular characterization is needed to elucidate the mechanistic basis of MLH1 epimutations and their heritability/reversibility.
2017-11-28 | GSE107352 | GEO
Project description:Meiosis, a reductional cell division, relies on precise initiation, maturation and resolution of crossovers (COs)-connections between homologs chromosomes-to ensure their accurate segregation during metaphase I. This process is finely regulated in eukaryotes by the interplay of RING-E3 ligases such as Rnf212 and Hei10 in mammals. In this study, we functionally characterized a novel RNF212B E3 ligase. RNF212B co-localizes and interacts with RNF212 forming numerous small foci at zygotene. These consolidate into larger foci at mature COs, colocalizing with Hei10 and MLH1 at pachytene on a synapsis-dependent and DSB-independent manner. Moreover, Rnf212b interacts with pro-COs proteins such as Tex11, MSH4 and RPA and other recombination proteins. Genetically, RNF212B foci depend on the presence of RNF212 and MSH4 but not on Hei10 and CNTD1. Rnf212b-deficient and -enzymatic-dead mutant mice exhibit modest synapsis defects a reduction in pro-CO factors (MSH4, TEX11, RPA, MZIP2) and a complete loss of MLH1-staining of COs, resulting in metaphase I with most univalents. Double mutants for RNF212b and RNF212 exhibit an identical phenotype, while double heterozygous demonstrate a dosage-dependent reduction in the number of COs relative to the single mutant, indicating a functional interplay between both paralogs. SUMOylome analysis of testis from Rnf212b mutants and pull-down analysis of Sumo- and Ubiquitin-tagged Hela cells, suggest that RNf212B is a novel E3 ligase with Ubiquitin activity, serving as a crucial factor for CO designation and maturation. This pathway holds physiological significance, with RNF212B and RNF212 genetic variants substantially contributing to the natural variation in genome-wide recombination rates in humans and mammals.
2024-05-31 | PXD047019 | Pride
Project description:As part of collaboration between UCLA and CHDI, UCLA is creating knockouts (KOs) of 123 genes, implicated in Huntington’s disease (HD) through various computational modeling efforts. Striatum and cortex were isolated from 6-month-old Mlh1+/- mice crossed with the Q140 knock-in (KI) HD mice and their respective controls. Transcriptomic analysis (RNASeq) was performed on 4 genotypes: WT, Mlh1+/-, Q140, and Q140 X Mlh1+/-, 8 replicates per genotype.
2025-02-10 | GSE229811 | GEO
Project description:Lynch syndrome, caused by germline heterozygous mutations of the DNA mismatch repair genes MLH1, MSH2, MSH6 and PMS2, or deletions affecting the EPCAM gene upstream of MSH2, is characterized by a predisposition to early-onset colorectal and additional extracolonic cancers. An alternative but rare cause of Lynch syndrome is a constitutional epimutation of MLH1, which is characterized by promoter methylation and transcriptional silencing of a single allele in normal tissues. Worldwide, five families with autosomal dominant transmission of a constitutional MLH1 epimutation linked to an MLH1 haplotype with two single nucleotide variants (c.-27C>A and c.85G>T) have been identified. Array-based genotyping using Affymetrix SNP 6.0 data in four of these families revealed a shared haplotype extending across a ≤2.6 Mb region of chromosome 3p22 encompassing MLH1 and additional flanking genes, indicating common ancestry. Genomic DNA from 5 carriers of the c.-27C>A and c.85G>T variants was hybridized on Affymetrix SNP6.0 array according to manufacturer's procedures
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