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ABSTRACT:
PROVIDER: PRJEB22901 | ENA |
REPOSITORIES: ENA
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Project description:The mismatch repair (MMR) family is a highly conserved group of proteins that function in correcting base-base and insertion-deletion mismatches generated during DNA replication. To systematically investigate the mismatch repair pathway, we conducted a proteomic analysis and identified MMR-associated protein complexes using a tandem-affinity purification coupled with mass spectrometry (TAP-MS) method. In total, we identified 262 high-confidence candidate interaction proteins (HCIPs).
2016-02-08 | PXD003014 | Pride
Project description:The mismatch repair (MMR) family is a highly conserved group of proteins that function in correcting base-base and insertion-deletion mismatches generated during DNA replication. To systematically investigate the mismatch repair pathway, we conducted a proteomic analysis and identified MMR-associated protein complexes using a tandem-affinity purification coupled with mass spectrometry (TAP-MS) method. In total, we identified 262 high-confidence candidate interaction proteins (HCIPs).
2016-03-13 | MSV000079578 | MassIVE
Project description:In yeast, DNA breaks are usually repaired by homologous recombination (HR). An early step for HR pathways is formation of a heteroduplex, in which a single-strand from the broken DNA molecule pairs with a strand derived from an intact DNA molecule. If the two strands of DNA are not identical, there will be mismatches within the heteroduplex DNA (hetDNA). In wild-type strains, these mismatches are repaired by the mismatch repair (MMR) system, producing a gene conversion event. In strains lacking MMR, the mismatches persist. Most previous studies involving hetDNA formed during mitotic recombination were restricted to one locus. Below, we present a global mapping of hetDNA formed in the MMR-defective mlh1 strain. We find that many recombination events are associated with repair of double-stranded DNA gaps and/or involve Mlh1-independent mismatch repair. Many of our events are not explicable by the simplest form of the double-strand break repair model of recombination.
2017-06-27 | GSE100497 | GEO
Project description:We show that mismatch-repair (MMR) signature mutations can activate colorectal cancer (CRC)-specific enhancers, through analysis of enhancer DNA associated with the active enhancer histone mark H3K27ac. We demonstrate that MMR mutations activate enhancers using a xenograft metastasis model, where mutations are induced naturally via CRISPR/Cas9 inactivation of MLH1 prior to tumor cell injection.
2019-02-07 | GSE126188 | GEO
Project description:There is mounting evidence that mismatch repair (MMR) proteins are involved in oxidative DNA damage response. SETD2, the histone H3K36 tri-methyltransferase, is a newly found factor participate in MMR pathway in human cells. In this study, we show that SETD2 can directly interact with MMR protein MutSα, and they are enriched and colocalized in chromatin in response to oxidative damage, which maybe the reason for the amplification of H3K36me3. Moreover, MutSα and SETD2 are essential for ATM and CHK2 activation upon H2O2 treatment, loss of SETD2 and MutSα will display impaired DNA damage response and oxidative DNA repair, which will accumulate oxidative damage and lead to more cell apoptosis and cell death. Our finding provided a novel SETD2 dependent mechanism for the oxidative DNA damage response together with MMR protein.
2022-07-06 | GSE163940 | GEO
Project description:DNA mismatch repair (MMR) is an evolutionarily conserved process that corrects innate DNA polymerase infidelities during replication to maintain genomic integrity. Defects in a subset of MMR genes are associated with hereditary non-polyposis colon cancer and some other sporadic cancers, highlighting the crucial role for MMR in genome maintenance. In E. coli a helicase implicated in the MMR process is well characterized, and named UvrD, whereas in mammals it has not been identified yet, even though the eukaryotic DNA mismatch pathway is analogous to the bacterial one and uses a similar repair mechanism and key components. Here we identify MCM9 as a helicase playing a vital role in MMR in mammals. MCM9 is the last discovered member of the MCM2-9 family, and has been implicated in replication and homologous recombination processes. By an affinity-purification proteomic approach, we found that MCM9 interacts with the MMR initiation complex. Immortalized cells from MCM9 knockout mice showed clear length alterations in their microsatellites, and a dramatic MMR deficiency compared to wild-type cells. We also found that a helicase-dead form of MCM9 is totally unable to restore the MMR deficiency phenotype. Furthermore, using an siRNA approach in human cells, we demonstrated that MCM9 is regulated by MSH2, a protein responsible for mismatch recognition. Our results clearly reveal that MCM9 functions as a helicase for DNA mismatch repair in mammals, and thus is essential for the maintenance of genome stability. Proteomics analysis: FLAG-HA-tagged human MCM9 plus associated proteins were isolated by tandem affinity purification from nuclear extracts of stably-expressing HeLa S3 cells, then analysed by SDS-PAGE and silver staining. Gel lanes were cut into slices, which were processed and analysed separately. Proteins in each gel slice were digested with trypsin, extracted and analysed by LC-MS/MS on a Thermo Scientific LTQ Velos mass spectrometer, generating a series of MS RAW files. Bioinformatics: Peptide and protein identification from MS data was performed using the Sequest program, with a human IPI sequence database (v.3.60). Trypsin was defined as the protease used, a peptide mass tolerance of 2.5 was specified, and all peptide matches have a Sequest Xcorr score ≥0.5.
2015-08-19 | PXD000212 | Pride
Project description:An enduring issue in evolutionary and cancer biology is how replication infidelity influences genome composition and vice versa. Here we examine this issue by sequencing the genomes of diploid budding yeast strains that are either mismatch repair (MMR) proficient or deficient and encode wild type or mutator variants of the three major nuclear DNA replicases. Analysis of over 43,000 mutations that accumulated in the absence of selective pressure demonstrates that the nuclear DNA replication machinery generates less than one mismatch per genome and in combination with MMR, achieves a genome-wide per base error rate of 1.7 x 10-10. Absent both MMR and purifying selection, replication error patterns strongly depend on replication origin proximity, replication fork direction, and the local DNA sequence. Preferred sequences were observed for base substitutions and deletions. Error rates also vary with replication time, in linker versus nucleosome-bound DNA, in 5'- and 3'-untranslated regions, in coding regions and in intergenic DNA. This genome-wide view shows that replication fidelity is amazingly high but heterogeneous, in patterns that suggest the underlying mechanisms by which replication modulates genome stability and composition and vice versa. Six to ten isolates were sequenced for each combination of DNA polymerase (WT, pol1-L868M, pol2-M644G, pol3-L612M) and mismatch repair (proficient, deficient) genotypes. A single WT isolate was sequenced following micrococcal nuclease digestion.
2014-08-25 | E-GEOD-56939 | biostudies-arrayexpress
Project description:Mass spectrometry based PTM phosphorylation analysis to study regulation mechanism of MUTL alpha, a heterodimer consisting of MLH1 and PMS2 and a key player in DNA mismatch repair (MMR). It could be demonstrated that phosphorylation of MLH1 by Casein Kinase II (CK2) at amino acid position 477 can switch off MMR activity in vitro.
2018-08-29 | PXD009026 | Pride
Project description:Inherited defects in the base-excision repair gene MBD4 predispose individuals to adenomatous polyposis and colorectal cancer, which is characterized by an accumulation of C>T transitions resulting from spontaneous deamination of 5’-methylcytosine. Despite its significance, this DNA repair pathway is still poorly understood. Here we show that the protein MBD4 is required for DNA methylation maintenance and G/T mismatch repair. Transcriptome and methylome analyses reveal a genome-wide hypomethylation of promoters, gene bodies and repetitive elements in the absence of MBD4 in vivo. Methylation mark loss is accompanied by a broad transcriptional derepression phenotype affecting promoters and retroelements with low methylated CpG density. MBD4 in vivo forms a complex with the mismatch repair proteins (MMR), which exhibits high bi-functional glycosylase/AP-lyase endonuclease specific activity towards methylated DNA substrates containing a G/T mismatch. Experiments using recombinant proteins reveal that the association of MBD4 with the MMR protein MLH1 is required for this activity. The described data identify MBD4 as an enzyme specifically designed to repair deaminated 5-methylcytosines and illustrates how MBD4 functions in normal and pathological conditions.
2022-01-10 | GSE84319 | GEO
Project description:Inherited defects in the base-excision repair gene MBD4 predispose individuals to adenomatous polyposis and colorectal cancer, which is characterized by an accumulation of C>T transitions resulting from spontaneous deamination of 5’-methylcytosine. Despite its significance, this DNA repair pathway is still poorly understood. Here we show that the protein MBD4 is required for DNA methylation maintenance and G/T mismatch repair. Transcriptome and methylome analyses reveal a genome-wide hypomethylation of promoters, gene bodies and repetitive elements in the absence of MBD4 in vivo. Methylation mark loss is accompanied by a broad transcriptional derepression phenotype affecting promoters and retroelements with low methylated CpG density. MBD4 in vivo forms a complex with the mismatch repair proteins (MMR), which exhibits high bi-functional glycosylase/AP-lyase endonuclease specific activity towards methylated DNA substrates containing a G/T mismatch. Experiments using recombinant proteins reveal that the association of MBD4 with the MMR protein MLH1 is required for this activity. The described data identify MBD4 as an enzyme specifically designed to repair deaminated 5-methylcytosines and illustrates how MBD4 functions in normal and pathological conditions.
2022-01-10 | GSE84497 | GEO