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ABSTRACT:
PROVIDER: PRJEB11440 | ENA |
REPOSITORIES: ENA
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Project description:Mre11, together with Rad50 and Xrs2/NBS, plays pivotal roles in homologous recombination, repair of DNA double strand breaks (DSBs), activation of damage-induced checkpoint, and telomere maintenance. Using DNA microarray assays to analyze yeast mutants (mre11delta, rad50delta, and spo11Y135F) defective for meiotic DSB formation, we demonstrate that the absence of Mre11 in yeast causes specific effects on regulation of a class of meiotic genes for spore development. The transcriptional deficiency was not observed in other DSB mutants such as rad50delta and spo11Y135F, suggesting the transcriptional defect in mre11delta is due to neither lack of meiotic DSB formation, nor disintegrity of Mre11-Rad50-Xrs2 complex.These defects were confirmed by northern and lacZ reporter gene assays. Keywords: mutant vs. wildtype strains
2007-04-10 | GSE6620 | GEO
Project description:Mre11, together with Rad50 and Xrs2/NBS, plays pivotal roles in homologous recombination, repair of DNA double strand breaks (DSBs), activation of damage-induced checkpoint, and telomere maintenance. Using DNA microarray assays to analyze yeast mutants (mre11delta, rad50delta, and spo11Y135F) defective for meiotic DSB formation, we demonstrate that the absence of Mre11 in yeast causes specific effects on regulation of a class of meiotic genes for spore development. The transcriptional deficiency was not observed in other DSB mutants such as rad50delta and spo11Y135F, suggesting the transcriptional defect in mre11delta is due to neither lack of meiotic DSB formation, nor disintegrity of Mre11-Rad50-Xrs2 complex.These defects were confirmed by northern and lacZ reporter gene assays. Experiment Overall Design: Gene expression data from wild type, mre11delta, rad50delta, and spo11Y135F cells in premeiosis (meiosis 0 hr) and prophase (meiosis 4 hr). Affymetrix GeneChip YG-S98 was used. All strains used were SK1 background diploid cells.
2007-10-23 | E-GEOD-6620 | biostudies-arrayexpress
Project description:Deletion mutants of the yeast MRX complex (Rad50, Mre11 and Xrs2) were studied for gene expression levels. Significant difference in expression levels was observed in genes pertaining to DNA damage, cell cycle etc. as compared to the BY4741 wild type.
2015-12-31 | GSE48538 | GEO
Project description:Deletion mutants of the yeast MRX complex (Rad50, Mre11 and Xrs2) were studied for gene expression levels. Significant difference in expression levels was observed in genes pertaining to DNA damage, cell cycle etc. as compared to the BY4741 wild type. Organism : Saccharomyces cerevisiae , Custom Saccharomyces cerevisiae 8x15k Gene expresssion Microarray (AMADID: 016333) designed by Genotypic Technology Private Limited
2015-12-31 | E-GEOD-48538 | biostudies-arrayexpress
Project description:The Mre11 complex (Mre11, Rad50, and Nbs1) and Chk2 have been implicated in the DNA damage response, an inducible process required for the suppression of malignancy. The Mre11 complex is predominantly required for repair and checkpoint activation in S phase, while Chk2 governs apoptosis. We examined the relationship between the Mre11 complex and Chk2 in the DNA damage response via the establishment of Nbs1âB/âB Chk2-/- and Mre11ATLD1/ATLD1 Chk2-/- mice. Chk2 deficiency did not modify the checkpoint defects or chromosomal instability of Mre11 complex mutants; however, the double mutant mice exhibited synergistic defects in DNA damage-induced p53 regulation and apoptosis. Nbs1âB/âB Chk2-/- and Mre11ATLD1/ATLD1 Chk2-/- mice were also predisposed to tumors. In contrast, DNA-PKcs deficient mice, in which G1-specific chromosome breaks are present, did not exhibit synergy with Chk2-/- mutants. These data suggest that Chk2 suppresses the oncogenic potential of DNA damage arising during S and G2 phases of the cell cycle. Experiment Overall Design: Thymocytes from Wild type (Wt), Atm-/- and Chk2-/- mice were exposed to mock 5 Gy radiation (IR). The RNA was harvested 8 hours post treatment.
2008-06-20 | E-GEOD-11436 | biostudies-arrayexpress
Project description:Rad50 is a component of the conserved MRE11-RAD50-NBS1 (MRN) complex, which functions in genome stability and the cell’s ability to deal with stalled DNA replication forks. We identified Rad50 as a factor important for R-loop tolerance and thus mapped DNA:RNA hybrids in Rad50KO cells and compare them to previously reported wild-type and Sgs1KO profiles.
2019-10-31 | E-MTAB-7885 | biostudies-arrayexpress
Project description:The genomic DNAs of strains 263 of L. infantum and five derived independent resistant mutants to 5-fluorouracil were used in comparative genomic hybridizations to reveal the deletion and/or amplification events occured by drug resistance mechanisms. The human protozoan parasites Leishmania are prototrophic for pyrimidines and de novo pyrimidine biosynthesis is necessary for their growth. Five independent L. infantum mutants were selected for resistance to the pyrimidine analogue 5-fluorouracil (5-FU) in the hope to better understand the metabolism of pyrimidine in Leishmania. Analysis of the 5-FU mutants by comparative genomic hybridization and whole genome sequencing revealed amplification and deletion events as well as point mutations in metabolic genes involved in either the uridine salvage, folate or dTMP biosynthesis pathways. In particular, a dhfr-ts containing amplicon was observed in two mutants and a deletion of part of chromosome 10 was detected in one mutant. Point mutations in uridine phosphorybosyl transferase (UPRT), thymidine kinase (TK) and uridine phosphorylase (UP) were also discovered. Transfection experiments confirmed that these molecular alterations were responsible for the 5-FU resistance phenotype. Transport studies revealed that one resistant mutant was defective for uracil and 5-FU import although the identity of the transporter remains elusive. This study provided further insights in pyrimidine metabolism in Leishmania and confirmed that multiple mutations can co-exist in a cell to lead to resistance. Each independent resistant mutant to 5-fluorouracil was hybridizated with the wild-type L. infantum 263 to 10 microarrays, each with three biological replicates (independent cultures).
2013-12-31 | E-GEOD-45866 | biostudies-arrayexpress
Project description:The Mre11 complex (Mre11, Rad50, and Nbs1) and Chk2 have been implicated in the DNA damage response, an inducible process required for the suppression of malignancy. The Mre11 complex is predominantly required for repair and checkpoint activation in S phase, while Chk2 governs apoptosis. We examined the relationship between the Mre11 complex and Chk2 in the DNA damage response via the establishment of Nbs1∆B/∆B Chk2-/- and Mre11ATLD1/ATLD1 Chk2-/- mice. Chk2 deficiency did not modify the checkpoint defects or chromosomal instability of Mre11 complex mutants; however, the double mutant mice exhibited synergistic defects in DNA damage-induced p53 regulation and apoptosis. Nbs1∆B/∆B Chk2-/- and Mre11ATLD1/ATLD1 Chk2-/- mice were also predisposed to tumors. In contrast, DNA-PKcs deficient mice, in which G1-specific chromosome breaks are present, did not exhibit synergy with Chk2-/- mutants. These data suggest that Chk2 suppresses the oncogenic potential of DNA damage arising during S and G2 phases of the cell cycle. Keywords: Global gene expression analysis, response to radiation, Nbs1∆B/∆B Chk2-/- and Mre11ATLD1/ATLD1 Chk2-/- mutant mice
2008-05-15 | GSE11436 | GEO
Project description:Programed DNA double-strand breaks (DSBs) catalyzed by the topoisomerase II-like enzymes, SPO11 and TOPVIBL, initiate meiotic recombination. Following DSB formation, the MRE11-RAD50-NBS1/Xrs2 (MRN/X) complex, along with EXO1 and DNA2, cleave the SPO11-DNA to generate 3′ single-stranded DNA (ssDNA) ends, which are prerequisite for meiotic DSB repair. In both yeast and mammals, MRE11 exhibits endonucleolytic cleavage of the 5′ terminated DNA strand in the vicinity of the DSBs and exonucleolytic resection from 3′ to 5′ towards the DSB ends. RAD50 is a structure maintenance of chromosome (SMC) related protein that contains one ATPase domain at its N- and C- terminal ends, respectively, Zn hook, and anti-parallel coiled coils. RAD50 plays a crucial role in facilitating the MRE11 nuclease activity on DSBs by ATP binding and hydrolysis. However, the in vivo function of Rad50 in mammalian germ cells, particularly its in vivo role in the resection of meiotic DSB ends at the molecular level remains elusive. Here, we performed END-seq with synchronized zygotene spermatocytes from control and germ cell specific Rad50 mutant (Rad50-sKO) mice. We find that the number of formed DSB in the mutant spermatocytes was reduced compared to control spermatocytes (6 636 DSBs in Rad50-sKO spermatocytes vs 8 168 in control spermatocytes) and abnormal DSB end resection occurred in mutant spermatocytes (DSB end resection length: 1 279 nts in Rad50-sKO spermatocytes vs 1 923 nts in control spermatocytes). Thus, RAD50 is essential for DSB formation and end resection during mammalian meiosis.
2024-04-02 | GSE262706 | GEO