Re-replication generates whole-chromosomal instability and anueploidy
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ABSTRACT:
ORGANISM(S): Saccharomyces cerevisiae
PROVIDER: GSE55641 | GEO | 2014/07/25
SECONDARY ACCESSION(S): PRJNA240280
REPOSITORIES: GEO
Similar Datasets
Project description:Aneuploidy, a hallmark of cancer, often arises from whole chromosome instability (W-CIN). Many cancers exhibiting W-CIN, however, show no direct insult to the mitotic proteins that ensure proper segregation of chromosomes. This has stimulated interest in identifying defects in non-mitotic processes that might disrupt chromosome behavior in mitosis. Here we show in Saccharomyces cerevisiae that re-replication of centromeric DNA, caused by deregulation of replication initiation proteins, efficiently induces chromosome instability––either by causing missegregation of both sister chromatids to one daughter cell or by triggering formation of an extra chromatid through a pathway dependent on homologous recombination. Given the emerging connections between the deregulation of replication initiation proteins and oncogenesis, our findings offer the possibility of a new non-mitotic source of W-CIN and aneuploidy that may be relevant to cancer. Diploid strains containing a re-replicating locus were induced to re-replicate through a centromere. This compilation includes the analysis of the re-replication, as well as the copy-number determination of alleged aneuploid colonies from various backgrounds. Series contains a total of 194 copy number hybridizations and 8 re-replication profile hybridizations. Note that the VALUE field reported for all of the sample tables in this series are the log2 of the normalized Cy3/Cy5 ratio. To convert these into usable copy number profiles raise 2 to the indicated VALUE.
2014-07-25 | E-GEOD-55641 | biostudies-arrayexpress
Project description:Chromosome instability (CIN) leads to aneuploidy and copy number variations (CNVs). Even though both are hallmarks of cancer cells, aneuploidy inhibits proliferation of untransformed cells, suggesting that cancer cells have adapted to cope with CIN. The spindle assembly checkpoint (SAC) prevents CIN by monitoring chromosome attachment and sister chromatid tension in mitosis. By conditionally inactivating Mad2, an essential SAC gene, we find that SAC inactivation in T-cells or hepatocytes is remarkably well tolerated and becomes tumorigenic when placed in a p53null or p53+/- predisposed background. The resulting T-ALLs and HCCs are highly aneuploid, exhibit clonal copy number changes that are tumor specific despite ongoing CIN, indicating that CIN is a powerful driver of tumor evolution.
2017-03-20 | GSE63688 | GEO
Project description:Transcriptome analysis to map transcriptomes of Mad2 p53null-driven aneuploid liver cancers and T-ALLs, to determine correlation between copy number changes and expression changes and to map the transcriptional response to CIN Chromosome instability (CIN) leads to aneuploidy and copy number variations (CNVs). Even though both are hallmarks of cancer cells, aneuploidy inhibits proliferation of untransformed cells, suggesting that cancer cells have adapted to cope with CIN. The spindle assembly checkpoint (SAC) prevents CIN by monitoring chromosome attachment and sister chromatid tension in mitosis. By conditionally inactivating Mad2, an essential SAC gene, we find that SAC inactivation in T-cells or hepatocytes is remarkably well tolerated and becomes tumorigenic when placed in a p53null or p53+/- predisposed background. The resulting T-ALLs and HCCs are highly aneuploid, exhibit clonal copy number changes that are tumor specific despite ongoing CIN, indicating that CIN is a powerful driver of tumor evolution.
2017-03-20 | GSE63687 | GEO
Project description:Mad2 and p53 loss were combined in liver or T-cells specificely leading to early onset and highly aggressive aneuploid HCC and T-ALL. Tumours were characterized for (recurrrent) copy number changes with a focus on whole chromosome abnormalities. DNA content was compared to the DNA content of sex-matched uninfiltrated control liver samples from litter mates Chromosome instability (CIN) leads to aneuploidy and copy number variations (CNVs). Even though both are hallmarks of cancer cells, aneuploidy inhibits proliferation of untransformed cells, suggesting that cancer cells have adapted to cope with CIN. The spindle assembly checkpoint (SAC) prevents CIN by monitoring chromosome attachment and sister chromatid tension in mitosis. By conditionally inactivating Mad2, an essential SAC gene, we find that SAC inactivation in T-cells or hepatocytes is remarkably well tolerated and becomes tumorigenic when placed in a p53null or p53+/- predisposed background. The resulting T-ALLs and HCCs are highly aneuploid, exhibit clonal copy number changes that are tumor specific despite ongoing CIN, indicating that CIN is a powerful driver of tumor evolution.
2017-03-20 | GSE63686 | GEO
Project description:The ring-shaped cohesin complex links sister chromatids until their timely segregation during mitosis. Cohesin is enriched at centromeres, where it provides the cohesive counter-force to bi-polar tension produced by the mitotic spindle. As a consequence of spindle tension, centromeric sequences transiently split in pre-anaphase cells, in some organisms up to several micrometeres. This ‘centromere breathing’ presents a paradox, how sister sequences separate where cohesin is most enriched. We now show that in the budding yeast S. cerevisiae, cohesin binding diminishes over centromeric sequences that split during breathing. We see no evidence for cohesin translocation to surrounding sequences, suggesting that cohesin is removed from centromeres during breathing. Two pools of cohesin can be distinguished. Cohesin loaded before DNA replication, that has established sister chromatid cohesion, disappears during breathing. In contrast, cohesin loaded after DNA replication is partly retained. As sister centromeres re-associate after transient separation, cohesin is re-loaded in a manner independent of the canonical cohesin loader Scc2/Scc4. Efficient centromere re-association requires the cohesion establishment factor Eco1, suggesting that re-establishment of sister chromatid cohesion contributes to the dynamic behaviour of centromeres in mitosis. These findings provide new insights into cohesin behaviour at centromeres. Keywords: ChIP-chip
2007-09-30 | GSE8661 | GEO
Project description:The fidelity of chromosome duplication through cell divisions requires timely binding and release of the cohesin. Cohesin is a ring-shaped protein complex linking newly replicated sister chromatids to ensure their appropriate transmission through mitosis. Upon commencement of mitosis cohesin is removed from DNA in two steps: first, from chromosome arms resulting in sister chromatid resolution, and, second, from centromers leading to sister chromatid segregation. As DNA of eukaryotic chromosomes is assembled into chromatin, regulation of sister chromatid cohesion-segregation may involve chromatin modifying machinery, but this link is not well understood. Here we report that H2A-H2B histone chaperone NAP1, a factor, which is primarily implicated in chromatin assembly, is required for cohesin release from mitotic chromosome arms. NAP1 and cohesin protein complex interact directly and share multiple binding sites on chromatin. Depletion of the NAP1 hinders cohesin removal during mitosis resulting in accumulation of unresolved sister chromatids. Thus, in addition to its well established functions in chromatin dynamics, histone chaperone NAP1 coordinates cell cycle dependent cohesin release. These results reveal a novel molecular pathway for sister chromatid resolution and emphasizes a role for histone chaperones in control of eukaryotic genome replication and transmission.
2012-07-26 | GSE30938 | GEO
Project description:The fidelity of chromosome duplication through cell divisions requires timely binding and release of the cohesin. Cohesin is a ring-shaped protein complex linking newly replicated sister chromatids to ensure their appropriate transmission through mitosis. Upon commencement of mitosis cohesin is removed from DNA in two steps: first, from chromosome arms resulting in sister chromatid resolution, and, second, from centromers leading to sister chromatid segregation. As DNA of eukaryotic chromosomes is assembled into chromatin, regulation of sister chromatid cohesion-segregation may involve chromatin modifying machinery, but this link is not well understood. Here we report that H2A-H2B histone chaperone NAP1, a factor, which is primarily implicated in chromatin assembly, is required for cohesin release from mitotic chromosome arms. NAP1 and cohesin protein complex interact directly and share multiple binding sites on chromatin. Depletion of the NAP1 hinders cohesin removal during mitosis resulting in accumulation of unresolved sister chromatids. Thus, in addition to its well established functions in chromatin dynamics, histone chaperone NAP1 coordinates cell cycle dependent cohesin release. These results reveal a novel molecular pathway for sister chromatid resolution and emphasizes a role for histone chaperones in control of eukaryotic genome replication and transmission. Genome-wide NAP1 and Cohesin ChIP-chip profiling in Drosophila S2 cells. The supplementary bed file S2_cohesin_sites.bed contains cohesin binding sites obtained by intersecting the sets of significant ChIP-chip peaks for SA (a cohesin subunit; stromalin) and SMC1.
2012-07-25 | E-GEOD-30938 | biostudies-arrayexpress
Project description:Sister chromatid cohesion (SCC), the pairing of sister chromatids following DNA replication until mitosis, is established by loading of the cohesin complex on newly replicated chromatids. Cohesin must then be maintained until mitosis to prevent segregation defects and aneuploidy. However, how SCC is established and maintained until mitosis remains incompletely understood and emerging evidence suggests that replication stress may lead to premature SCC loss. Here, we report that the single-stranded DNA-binding protein CTC1-STN1-TEN1 (CST) aids in SCC. CST primarily functions in telomere length regulation but also has known roles in replication restart and DNA repair. Following depletion of CST subunits, we observed an increase in the complete loss of SCC. Additionally, we determined that CST associates with the cohesin complex. Unexpectedly, we did not find evidence of altered cohesion or mitotic progression in the absence of CST; however, we did find that treatment with various replication inhibitors increased the association between CST and cohesin. Since replication stress was recently shown to induce SCC loss, we hypothesized that CST may be required to maintain or remodel SCC following DNA replication fork stalling. In agreement with this idea, SCC loss was greatly increased in CST-depleted cells following exogenous replication stress. Based on our findings, we propose that CST aids in the maintenance of SCC at stalled replication forks to prevent premature cohesion loss.
2021-07-28 | PXD026264 | Pride
Project description:Chromosomal instability (CIN), defined as an increased occurrence of chromosome segregation errors during cell division, is a prominent form of genomic instability (Bakhoum and Avi Landau, 2017). It is the major cause of aneuploidy, an imbalanced complement of whole chromosomes or chromosome arms, which is the most prevalent genetic alteration in human cancers (Vasudevan et al., 2021; Santaguida and Amon, 2015). Importantly, aneuploidy is commonly associated with ongoing CIN through consecutive cell divisions (Shelzer et al. 2011; Passerini et al., 2016), resulting in intratumor genetic heterogeneity, a central driver of cancer evolution and therapeutic resistance (Sansregret et al., 2018; Ben-David and Amon, 2019). Indeed, aneuploidy has been shown to act both as a tumor suppressor and as a tumor initiator (Weaver et al., 2007; Silk et al., 2013; Vasudevan et al., 2020), most likely depending on the specific chromosomes that are gained or lost (Ben-David et al., 2011; Sack et al., 2018; Adell et al., 2023). Despite the ubiquitous presence of CIN in several aneuploid cancer types and its clinical relevance, its presence in B-cell acute lymphoblastic leukemia (B-ALL) remains largely unexplored owing to the impaired proliferation of leukemic cells in vitro and the lack of reliable experimental models to comprehensively assess chromosome segregation in vivo. B-ALL is the most frequent childhood cancer, with 75% of cases occurring in children under 6 years of age, and it is characterized by the accumulation of highly proliferative immature B-cell precursors in the bone marrow (BM) (Hunger and Mullighan, 2015). The presence of CIN and its contribution to aneuploid cB-ALL progression is largely unknown due to the lack of preclinical models to study actively dividing cells. Accordingly, studies of CIN in cB-ALL are limited to the characterization of chromosomal copy-number heterogeneity (chr-CNH) in primary cB-ALL samples, but there is controversy over its presence due to the different techniques used to assess karyotype variability (Raimondi et al., 1996; Talamo et al., 2010; Alpar et al., 2014; Heerema et al.; 2007; Ramos-Muntada et al., 2022). Here, we explored the presence and the levels of CIN in different clinically-relevant aneuploid subtypes of cB-ALL using single-cell whole-genome sequencing (WGS) of primary samples to reliably assess chr-CNH, and by generating a large cohort of PDX models from primary cB-ALL samples (cB-ALL-PDX). Our results in cB-ALL-PDX models revealed variable levels of CIN in aneuploid cB-ALL subtypes, which significantly correlate with intraclonal karyotype heterogeneity and with disease progression. Additionally, mass-spectrometry analyses of cB-ALL-PDX samples revealed a CIN “signature” enriched in mitosis and chromosome segregation regulatory pathways. We speculate that this signature identifies adaptive mechanisms to ongoing CIN in aneuploid cB-ALL cells, which displayed a transcriptional signature characterized by an impaired mitotic spindle as observed by RNA-sequencing (RNA-Seq) analyses of a large cohort of primary cB-ALL patient samples. Our work might help to improve stratification of patients with cB-ALL with different levels of CIN who could benefit in the future from new therapeutic approaches aiming to target ongoing CIN.
2023-09-15 | PXD042785 | Pride
Project description:Tumors that overexpress the MYC oncogene frequently demonstrate aneuploidy, numerical chromosome alterations associated with highly aggressive cancers, rapid tumor evolution, and poor patient outcome. Here, we identify that MYC overexpression induces defects in microtubule nucleation and mitotic spindle assembly, promoting chromosome segregation defects, micronuclei and chromosomal instability (CIN). High TPX2 expression is permissive for mitotic spindle assembly and chromosome segregation in cells with MYC overexpression; whereas TPX2 depletion blocks mitotic progression, induces cell death and prevents tumor growth. Attenuating MYC expression reverses mitotic defects, even in established tumor cell lines, implicating an ongoing role for high MYC in the persistence of CIN in tumors. Our studies implicate the MYC oncogene as a regulator of spindle assembly and identify a new MYC-TPX2 synthetic-lethal interaction that could represent a future therapeutic strategy in MYC-overexpressing cancers. Moreover, our studies suggest that blocking MYC activity can attenuate the emergence of CIN and tumor evolution.
2020-03-30 | GSE130921 | GEO