EGAS00001002551-2-sc-20180615 - samples
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PROVIDER: EGAD00001004163 | EGA |
REPOSITORIES: EGA
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Project description:Abnormal numerical and structural chromosome content is frequently found in human cancer. However, the role of aneuploidy in tumor initiation and progression is poorly understood. To test the effect of aneuploidy on cancer development, we transiently induced chromosome instability (CIN) in mice by inducible overexpression of polo-like kinase 4 (PLK4), a master regulator of centrosome number. Short term increased PLK4 expression generated significant centrosome amplification and aneuploidy resulting in the formation of aggressive T cell lymphomas in mice with heterozygous inactivation of one p53 allele or accelerated tumor development in the absence of p53. Transient CIN increased the frequency of lymphoma-initiating cells, as revealed by T cell receptor sequencing of tumor samples. Transient CIN produced a unique tumor karyotype containing triploid chromosomes 4, 5, 14, and 15, as determined by whole genome sequencing.
2021-06-14 | GSE161728 | GEO
Project description:The duplication and segregation of chromosomes involve the dynamic re-organization of their internal structure by conserved architectural proteins, such as structural maintenance of chromosomes complexes (i.e., cohesin and condensin). Although the roles of these factors is actively investigated, a genome-wide view of chromosome dynamic architecture at both small and large-scales during cell division remains elusive. Here we report the first comprehensive 4D analysis of the Saccharomyces cerevisiae genome higher-order organization during the cell cycle, and investigate the roles of SMC in the observed structural transitions. During replication, cohesion establishment promotes long-range intra-chromosomal contacts and correlates with the individualization of chromosomes, which culminates at metaphase. Mitotic chromosomes are then abruptly reorganized in anaphase by mechanical forces exerted by the mitotic spindle. The formation of a condensin-dependent loop, that bridges the centromere cluster with the rDNA loci, suggests that condensin-mediated forces may also directly facilitate segregation. This work provides a comprehensive overview of chromosome dynamics during the cell cycle of a unicellular eukaryote that recapitulates and unveils new features of highly conserved stages of the cell division.
2017-07-20 | GSE90902 | GEO
Project description:Chromosomal abnormalities, such as structural and numerical abnormalities, are a common occurrence in cancer. The close association of homologous chromosomes during interphase, a phenomenon termed somatic chromosome pairing, has been observed in cancerous cells, but the functional consequences of somatic pairing have not been established. Gene expression profiling studies revealed that somatic pairing of chromosome 19 is a recurrent chromosomal abnormality in renal oncocytoma, a neoplasia of the adult kidney. Somatic pairing was associated with significant disruption of gene expression within the paired regions and resulted in the deregulation of the prolyl-hydroxylase EGLN2, a key protein that regulates the oxygen-dependent degradation of hypoxia-inducible factor (HIF). Overexpression of EGLN2 in renal oncocytoma increased ubiquitin-mediated destruction of HIF and concomitantly suppressed the expression of several HIF-target genes, including the pro-death BNIP3L gene. The transcriptional changes that are associated with somatic pairing of chromosome 19 mimic the transcriptional changes that occur following DNA amplification. Therefore, in addition to numerical and structural chromosomal abnormalities, alterations in chromosomal spatial dynamics should be considered as genomic events that are associated with tumorigenesis. The identification of EGLN2 as a significantly deregulated gene that maps within the paired chromosome region directly implicates defects in the oxygen-sensing network to the biology of renal oncocytoma. Keywords: Gene expression profiling, SNP analysis, renal, tumor Oncocytoma and Chromophobe RCC samples - expression profiling and SNP chip analysis
2010-05-25 | E-GEOD-8271 | biostudies-arrayexpress
Project description:Chromosomal abnormalities, such as structural and numerical abnormalities, are a common occurrence in cancer. The close association of homologous chromosomes during interphase, a phenomenon termed somatic chromosome pairing, has been observed in cancerous cells, but the functional consequences of somatic pairing have not been established. Gene expression profiling studies revealed that somatic pairing of chromosome 19 is a recurrent chromosomal abnormality in renal oncocytoma, a neoplasia of the adult kidney. Somatic pairing was associated with significant disruption of gene expression within the paired regions and resulted in the deregulation of the prolyl-hydroxylase EGLN2, a key protein that regulates the oxygen-dependent degradation of hypoxia-inducible factor (HIF). Overexpression of EGLN2 in renal oncocytoma increased ubiquitin-mediated destruction of HIF and concomitantly suppressed the expression of several HIF-target genes, including the pro-death BNIP3L gene. The transcriptional changes that are associated with somatic pairing of chromosome 19 mimic the transcriptional changes that occur following DNA amplification. Therefore, in addition to numerical and structural chromosomal abnormalities, alterations in chromosomal spatial dynamics should be considered as genomic events that are associated with tumorigenesis. The identification of EGLN2 as a significantly deregulated gene that maps within the paired chromosome region directly implicates defects in the oxygen-sensing network to the biology of renal oncocytoma. Keywords: Gene expression profiling, SNP analysis, renal, tumor
2008-08-13 | GSE8271 | GEO
Project description:The chromosomal condensin complex gives metaphase chromosomes structural stability. In addition, condensin is required for sister chromatid resolution during their segregation in anaphase. How condensin promotes chromosome resolution is poorly understood. Chromosome segregation during anaphase also fails after inactivation of topoisomerase II (topo II), the enzyme that removes catenation between sister chromatids left behind after completion of DNA replication. This has led to the proposal that condensin promotes DNA decatenation, but direct evidence for this is missing and alternative roles for condensin in chromosome resolution have been suggested. Using the budding yeast rDNA as a model, we now show that anaphase bridges in a condensin mutant are resolved by ectopic expression of a foreign (Chlorella virus) but not endogenous topo II. This suggests that catenation prevents sister rDNA segregation, and that yeast topo II is ineffective in decatenating the locus without condensin. Condensin and topo II colocalize along both rDNA and euchromatin, consistent with coordination of their activities. We investigate the physiological consequences of condensin-dependent rDNA decatenation and find that late decatenation determines the late segregation timing of this locus during anaphase. Regulation of decatenation therefore provides a means to finetune segregation timing of chromosomes in mitosis. Keywords: ChIP-chip, Cell Cycle
2008-07-18 | GSE11988 | GEO
Project description:Sexual reproduction relies on meiotic recombination and the accurate segregation of homologous chromosomes to generate viable, genetically diverse gametes. While the molecular mechanisms of recombination and chromosome segregation are well studied, the upstream regulatory cues that drive expression of key meiotic genes remain poorly understood, especially in metazoans. Emerging evidence suggests that post-transcriptional regulation plays a central role in initiating and coordinating the meiotic program in both fruit flies and mammals. Here, we identify the RNA-binding protein Ataxin-2 (Atx2) as a crucial regulator of meiosis in Drosophila melanogaster. We show that Atx2 positively regulates critical meiotic factors, especially components of the synaptonemal complex (SC), a structure essential for pairing, recombination and segregation of homologous chromosomes. In Atx2-depleted germ cells, SC component mRNA and protein levels are markedly reduced, leading to defective SC assembly and maintenance. Consequently, homologous chromosomes fail to pair properly, which is essential to ensure homolog segregation and prevent aneuploidy. These findings uncover Atx2 as a key regulator of the SC and highlight an underappreciated layer of gene regulation essential for accurate meiotic chromosome segregation and fertility.
2026-02-27 | GSE318364 | GEO
Project description:Chromatin fibres dynamically change their organisation during cell cycle. In interphase nucleus, chromatin fibres are evenly distributed whereas their spatial occupancy are reorganised to form condensed chromosomes in mitosis. This process called chromosome condensation is necessary for an accomplishment of faithful chromosome segregation. One of the Structural Maintenance of Chromosomes complexes, Condensin, is indispensable for chromosome condensation. It remains, however, unknown how Condensin plays its role in shaping mitotic chromosome. Here we show that chromatin fibres change their interacting partners; short-range contacts in interphase nucleus are converted into long-range interactions to shape condensed chromosomes. This conversion of interactions among chromatin fibres results in the formation of larger domains within mitotic chromosomes. Condensin is solely in charge of the conversion and large domain formation in fission yeast mitosis. Our results show how fission yeast Condensin is involved in shaping mitotic chromosomes.
2017-07-13 | GSE94475 | GEO
Project description:Chromatin fibres dynamically change their organisation during cell cycle. In interphase nucleus, chromatin fibres are evenly distributed whereas their spatial occupancy are reorganised to form condensed chromosomes in mitosis. This process called chromosome condensation is necessary for an accomplishment of faithful chromosome segregation. One of the Structural Maintenance of Chromosomes complexes, Condensin, is indispensable for chromosome condensation. It remains, however, unknown how Condensin plays its role in shaping mitotic chromosome. Here we show that chromatin fibres change their interacting partners; short-range contacts in interphase nucleus are converted into long-range interactions to shape condensed chromosomes. This conversion of interactions among chromatin fibres results in the formation of larger domains within mitotic chromosomes. Condensin is solely in charge of the conversion and large domain formation in fission yeast mitosis. Our results show how fission yeast Condensin is involved in shaping mitotic chromosomes.
2017-07-13 | GSE94474 | GEO
Project description:Gametes are produced via meiosis, a specialized cell division associated with frequent errors which cause birth defects and infertility. Uniquely in meiosis I, homologous chromosomes segregate to opposite poles, usually requiring their linkage by chiasmata, the products of crossover recombination1. The spindle checkpoint delays cell cycle progression until all chromosomes are properly attached to microtubules2 but the steps leading to the capture and alignment of chromosomes on the meiosis I spindle remain poorly understood. In budding yeast meiosis I, Mad2 and Mad3BUBR1 are equally important for spindle checkpoint delay, but biorientation of homologs on the meiosis I spindle requires Mad2, but not Mad3BUBR1 3,4. Here we show that Mad3BUBR1 promotes accurate meiosis I homolog segregation outside its canonical checkpoint role, independently of Mad2. We find that Mad3BUBR1 associates with the TOGL1 domain of Stu1CLASP, a conserved plus-end microtubule protein which is important for chromosome capture onto the spindle. Homologous chromosome pairs that are proficient in crossover formation, but which fail to biorient, rely on Mad3BUBR1-Stu1CLASP to ensure their efficient attachment to microtubules and segregation during meiosis I. Furthermore, we show that Mad3BUBR1-Stu1CLASP are essential to rescue the segregation of mini-chromosomes lacking crossovers. Our findings define a new pathway ensuring microtubule-dependent chromosome capture and demonstrate that spindle checkpoint proteins safeguard the fidelity of chromosome segregation both by actively promoting chromosome alignment and delaying cell cycle progression until this has occurred.
2024-07-18 | PXD048251 | Pride
Project description:X chromosome inactivation is a process that compensates X-linked gene dosage in mammalian female cells. The silencing of a randomly selected chromosome is accompanied by dramatic three-dimensional reorganization across the entire chromosome. To investigate the four-dimensional chromatin dynamics during early inactivation stages, we applied the multi-omics sequencing technique HiRES, which simultaneously detects three-dimensional genome and transcriptome in single cells, in a mouse embryonic stem cell line with induced random inactivation. The three-dimensional genome and transcriptome dual-omics data allowed us to identify random inactivation trajectories at single-cell resolution. We characterized multiple layers of X-chromosome reorganization and discovered a transient structural state shared by both X chromosomes, associated with biallelic Xist expression. By constructing single-cell inactivation trajectories, we found that most chromatin remodeling either accompanied or followed gene silencing. Further analysis of interaction decay kinetics revealed that TAD attenuation began from loss of interactions on TAD anchors. This study thus provides a detailed depiction of fine-scale chromatin reorganization during the initiation of random X chromosome inactivation.
2026-01-01 | GSE310759 | GEO