Ontology highlight
ABSTRACT:
PROVIDER: PRJNA896776 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR22138200.fastq.gz | Fastqsanger.gz | |||
| SRR22138200_1.fastq.gz | Fastqsanger.gz | |||
| SRR22138200_2.fastq.gz | Fastqsanger.gz | |||
| SRR22138201.fastq.gz | Fastqsanger.gz | |||
| SRR22138201_1.fastq.gz | Fastqsanger.gz |
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Similar Datasets
Project description:Mutation accumulation over time in normal somatic cells contributes to cancer development and is proposed as a cause of ageing. DNA polymerases POLE and POLD1 replicate DNA with high fidelity during normal cell divisions. However, in some cancers defective proofreading due to acquired mutations in the exonuclease domains of POLE or POLD1 causes markedly elevated somatic mutation burdens with distinctive mutational signatures. POLE and POLD1 exonuclease domain mutations also cause familial cancer predisposition when inherited through the germline. Here, we sequenced normal tissue DNA from individuals with germline POLE or POLD1 exonuclease domain mutations. Increased mutation burdens with characteristic mutational signatures were found to varying extents in all normal adult somatic cell types examined, during early embryogenesis and in sperm. Mutation burdens were further markedly elevated in neoplasms from these individuals. Thus human physiology is able to tolerate ubiquitously elevated mutation burdens. Indeed, with the exception of early onset cancer, individuals with germline POLE and POLD1 exonuclease domain mutations are not reported to show abnormal phenotypic features, including those of premature ageing. The results, therefore, do not support a simple model in which all features of ageing are attributable to widespread cell malfunction directly resulting from somatic mutation burdens accrued during life.
| EGAD00001006212 | EGA
Project description:Somatic mutations in the proofreading domain of the replicative DNA polymerase epsilon (POLE-exonuclease domain mutations, POLE-EDMs) are frequently found in colorectal and endometrial cancers and, occasionally, in other tumours. POLE-associated cancers typically display hypermutation, microsatellite stability and a unique mutational signature, with predominance of C > A transversions in the context TCT. To understand better the contribution of hypermutagenesis to tumour development, we have modelled the most recurrent POLE-EDM (POLE-P286R) in Schizosaccharomyces pombe. Whole-genome sequencing analysis revealed that the corresponding pol2-P287R also has a strong mutator effect in vivo, with high frequency of base substitutions and relatively few frameshift mutations. The mutations are equally distributed across different genomic regions, but they occur within an AT-rich context. The most abundant mutations are TCT > TAT transversions and, in contrast to human, TCG > TTG transitions are not elevated, likely due to the absence of cytosine methylation in fission yeast. The high mutation burden of pol2-P287R leads to increased sensitivity to elevated dNTP levels and DNA damaging agents and a phenotype that is exacerbated by depletion of the Pfh1 helicase. In addition, S phase is aberrant and RPA foci are elevated, suggestive of persistent ssDNA or DNA damage, and pol2-P287R shows synthetic lethality with rad3 deletion, indicative of checkpoint activation. Significantly, deletion of translesion polymerases kappa and eta partially suppresses pol2-P287R hypermutation, indicating that both enzymes contribute to this phenotype.
2021-06-11 | GSE169231 | GEO
Project description:DNA polymerase epsilon (Pole) carries out leading strand synthesis with high fidelity owing to its exonuclease activity. Pole polymerase and exonuclease activities are in balance, due to partitioning of nascent strands between catalytic sites, so that net end resection occurs when synthesis is impaired. Stalling of chromosomal DNA synthesis activates replication checkpoint kinases, required to preserve the functional integrity of replication forks. We found that Pole is phosphorylated in a Rad53CHK1-dependent manner upon fork stalling, likely to limit Pole-driven nascent strand resection that causes replication fork collapse. In stress conditions Pole phosphorylation occurs on serine 430 of the Pol2 catalytic subunit. A S430 phosphomimic limits strand partitioning and exonucleolytic processivity, while non-phosphorylatable Pol2-S430A bypasses checkpoint regulation causing stalled fork resection and collapse. We propose that checkpoint kinases switch Pole to an exonuclease-safe mode by curbing active site partitioning thus preventing nascent strand resection and stabilizing stalled replication forks.
2021-04-30 | GSE156480 | GEO
Project description:<p>The purpose of the original study was to search for somatic mutations in the tyrosine kinome of serous and clear cell endometrial carcinomas (human). The study was conducted in two phases.</p> <p>Phase 1: A mutation discovery screen, in which ~577 exons encoding the catalytic domains of 86 tyrosine kinases were PCR-amplified and bidirectionally Sanger sequenced from 24 serous, 11 clear cell, and 5 mixed histology endometrial tumors. This was followed by alignment of sequence reads to the human reference sequence and subsequent nucleotide variant calling to identify potential somatic (tumor-specific) mutations. Potential somatic mutations were confirmed by re-amplification and sequencing of the relevant tumor DNA as well as matched non-tumor ("normal") DNA from the same case.</p> <p>Phase 2: A mutation prevalence screen, in which the non-catalytic regions two tyrosine kinase genes, TNK2 and DDR1, were PCR-amplified and sequenced from the 40 discovery screen tumors, and all coding exons of TNK2 and DDR1 were PCR-amplified and sequenced from another 10 clear cell, 21 serous, and 41 endometrioid endometrial tumors, in an effort to identify additional somatic mutations in each gene. Exons encoding the exonuclease domain of POLE were also sequenced to document somatic mutations.</p>
| phs000841 | dbGaP
Project description:During genome replication, the leading strand DNA polymerase conducts continuous synthesis over long stretches of DNA within each replicon. Processive DNA synthesis supports symmetric progression of sister replication forks and efficient genome duplication. To address the mechanisms underlying leading strand polymerase-mediated synthesis, we examine one of its conserved domains, referred to as POPS, in the budding yeast Pol2 enzyme. We provide evidence that POPS supports replication fork symmetry and efficient genome replication via balancing the function of the Pol2 exonuclease domain. We found that the defective growth, slow S phase progression, and impaired genome synthesis associated with a POPS mutation were rescued by abolishing the Pol2 exonuclease activity. The suppressive effects further extended to the increased DNA re-arrangements in the POPS mutant and its negative genetic interactions with mutants of other genome maintenance factors. Significantly, our single molecule replicon-seq data demonstrate that the POPS mutant exhibited genome-wide replication fork asymmetry, and this defect was improved by eliminating the Pol2 exonuclease activity, thus providing a basis for its rescuing of a range of POPS mutant phenotypes. Collectively, these data suggest a model in which balanced activity between a unique Pol2 catalytic domain, and its exonuclease domain facilitates replication fork symmetry and genome maintenance.
2022-09-02 | GSE212101 | GEO
Project description:DNA polymerase epsilon (Pol epsilon) plays multiple roles in genome duplication and its catalytic subunit POLE suppresses tumorigenesis in humans. Despite its importance, we have limited understanding of Pol epsilon functional mechanisms and how its loss-of-function affects the evolution of cancer genomes. To address this issue, we used the budding yeast ortholog Pol2 to model cancer-associated POLE mutations that affect an uncharacterized yet highly conserved Pol2/POLE family-specific region. Analysis of pol2 mutants revealed an unexpected role for this region in the incorporation of Pol epsilon into the pre-loading complex during replisome assembly. Cellular and reconstitution experiments further identified a separate role for this region in promoting Pol epsilon polymerase activity. Unlike previously reported POLE mutations leading to hypermutation in cancer cells, the examined pol2 variants increase gross chromosomal rearrangements but not mutation rates. Our findings thus suggest that the Pol epsilon catalytic core integrates replisome assembly and DNA polymerization functions and that POLE tumor suppressive roles likely extend beyond limiting replication errors.
2020-03-29 | GSE132450 | GEO
Project description:Transcription termination was analyzed by anti RNA pol II ChIP-seq in isogenic human HEK293 cell lines that inducibly express a-amanitin resistant mutants of the RNA polymerase II large subunit with slow and fast elongation rates and in lines that inducbily over-express WT or an active site mutant of the RNA exonuclease "torpedo" Xrn2. Transcription termination zones were mapped by anti-pol II ChIP-seq under conditions where transcription elongation rate was increased or decreased by point mutations in the large subunit of the enzyme. Termination was also assayed under conditions where Xrn2 exonuclease activity was inhibited by over-expression of an active site mutant (D235A).
2015-11-19 | E-GEOD-72800 | biostudies-arrayexpress
Project description:Cohesin is present in almost all active enhancer regions, where it is associated with transcription factors. Cohesin frequently colocalizes with CTCF (CCCTC-binding factor), affecting genomic stability, expression and epigenetic homeostasis. Cohesin subunits are mutated in cancer, but CTCF/cohesin-binding sites (CBSs) in DNA have not been examined for mutations. Here we report frequent mutations at CBSs in cancers displaying a mutational signature where mutations in A•T base pairs predominate. Integration of whole-genome sequencing data from 213 colorectal cancer (CRC) samples and chromatin immunoprecipitation sequencing (ChIP-exo) data identified frequent point mutations at CBSs. In contrast, CRCs showing an ultramutator phenotype caused by defects in the exonuclease domain of DNA polymerase ɛ (POLE) displayed significantly fewer mutations at and adjacent to CBSs. Analysis of public data showed that multiple cancer types accumulate CBS mutations. CBSs are a major mutational hotspot in the noncoding cancer genome.
| EGAS00001003010 | EGA
Project description:Mutations in non-essential RSC genes was shown to cause spontaneous diploidization due to defective spindle pole body (SPB) duplication. RNA sequencing was performed to assess whether these effects were due to altered transcript profiles in rsc mutants
2018-05-30 | GSE106768 | GEO
Project description:Dis3 is a 3'-5' exonuclease and endonuclease that is conserved from bacteria to humans, and participates in the processing and degradation of many RNA species. DIS3 mutants suffer from impaired RNA processing, defective microtubules, growth retardation, and temperature sensitivity; however, the mechanisms by which DIS3 mutations influence cell cycle-related phenotypes remains largely unknown. Since the major impact of Dis3 mutation should be on the transcriptome, we performed an expression microarray on dis3E729K in order to elucidate the expression consequences of this allele.
2019-03-01 | GSE124143 | GEO