Browse
Submit Data
Databases
API
Help

Dataset Information

19 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Topoisomerase II deficiency leads to a postreplicative structural shift in all Saccharomyces cerevisiae chromosomes.

ABSTRACT: The key role of Topoisomerase II (Top2) is the removal of topological intertwines between sister chromatids. In yeast, inactivation of Top2 brings about distinct cell cycle responses. In the case of the conditional top2-5 allele, interphase and mitosis progress on schedule but cells suffer from a chromosome segregation catastrophe. We here show that top2-5 chromosomes fail to enter a Pulsed-Field Gel Electrophoresis (PFGE) in the first cell cycle, a behavior traditionally linked to the presence of replication and recombination intermediates. We distinguished two classes of affected chromosomes: the rDNA-bearing chromosome XII, which fails to enter a PFGE at the beginning of S-phase, and all the other chromosomes, which fail at a postreplicative stage. In synchronously cycling cells, this late PFGE retention is observed in anaphase; however, we demonstrate that this behavior is independent of cytokinesis, stabilization of anaphase bridges, spindle pulling forces and, probably, anaphase onset. Strikingly, once the PFGE retention has occurred it becomes refractory to Top2 re-activation. DNA combing, two-dimensional electrophoresis, genetic analyses, and GFP-tagged DNA damage markers suggest that neither recombination intermediates nor unfinished replication account for the postreplicative PFGE shift, which is further supported by the fact that the shift does not trigger the G₂/M checkpoint. We propose that the absence of Top2 activity leads to a general chromosome structural/topological change in mitosis.

SUBMITTER: Ayra-Plasencia J

PROVIDER: S-EPMC8298500 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Genome-Scale Genetic Interactions and Cell Imaging Confirm Cytokinesis as Deleterious to Transient Topoisomerase II Deficiency in Saccharomyces cerevisiae.

Project description:Topoisomerase II (Top2) is an essential protein that resolves DNA catenations. When Top2 is inactivated, mitotic catastrophe results from massive entanglement of chromosomes. Top2 is also the target of many first-line anticancer drugs, the so-called Top2 poisons. Often, tumors become resistant to these drugs by acquiring hypomorphic mutations in the genes encoding Top2 Here, we have compared the cell cycle and nuclear segregation of two coisogenic Saccharomyces cerevisiae strains carrying top2 thermosensitive alleles that differ in their resistance to Top2 poisons: the broadly-used poison-sensitive top2-4 and the poison-resistant top2-5 Furthermore, we have performed genome-scale synthetic genetic array (SGA) analyses for both alleles under permissive conditions, chronic sublethal Top2 downregulation, and acute, yet transient, Top2 inactivation. We find that slowing down mitotic progression, especially at the time of execution of the mitotic exit network (MEN), protects against Top2 deficiency. In all conditions, genetic protection was stronger in top2-5; this correlated with cell biology experiments in this mutant, whereby we observed destabilization of both chromatin and ultrafine anaphase bridges by execution of MEN and cytokinesis. Interestingly, whereas transient inactivation of the critical MEN driver Cdc15 partly suppressed top2-5 lethality, this was not the case when earlier steps within anaphase were disrupted; i.e., top2-5 cdc14-1 We discuss the basis of this difference and suggest that accelerated progression through mitosis may be a therapeutic strategy to hypersensitize cancer cells carrying hypomorphic mutations in TOP2.

| S-EPMC5633387 | biostudies-literature

Thiol peroxidase deficiency leads to increased mutational load and decreased fitness in Saccharomyces cerevisiae.

Project description:Thiol peroxidases are critical enzymes in the redox control of cellular processes that function by reducing low levels of hydroperoxides and regulating redox signaling. These proteins were also shown to regulate genome stability, but how their dysfunction affects the actual mutations in the genome is not known. Saccharomyces cerevisiae has eight thiol peroxidases of glutathione peroxidase and peroxiredoxin families, and the mutant lacking all these genes (?8) is viable. In this study, we employed two independent ?8 isolates to analyze the genome-wide mutation spectrum that results from deficiency in these enzymes. Deletion of these genes was accompanied by a dramatic increase in point mutations, many of which clustered in close proximity and scattered throughout the genome, suggesting strong mutational bias. We further subjected multiple lines of wild-type and ?8 cells to long-term mutation accumulation, followed by genome sequencing and phenotypic characterization. ?8 lines showed a significant increase in nonrecurrent point mutations and indels. The original ?8 cells exhibited reduced growth rate and decreased life span, which were further reduced in all ?8 mutation accumulation lines. Although the mutation spectrum of the two independent isolates was different, similar patterns of gene expression were observed, suggesting the direct contribution of thiol peroxidases to the observed phenotypes. Expression of a single thiol peroxidase could partially restore the growth phenotype of ?8 cells. This study shows how deficiency in nonessential, yet critical and conserved oxidoreductase function, leads to increased mutational load and decreased fitness.

| S-EPMC4224179 | biostudies-literature

Sir protein-independent repair of dicentric chromosomes in Saccharomyces cerevisiae.

Project description:Sir2 protein has been reported to be recruited to dicentric chromosomes under tension, and such chromosomes are reported to be especially vulnerable to breakage in sir2? mutants. We found that the loss of viability in such mutants was an indirect effect of the repression of nonhomologous end joining in Sir(-) mutants and that the apparent recruitment of Sir2 protein to chromosomes under tension was likely due to methodological weakness in early chromatin immunoprecipitation studies.

| S-EPMC5025274 | biostudies-literature

Metabolic response to iron deficiency in Saccharomyces cerevisiae.

Project description:Iron is an essential cofactor for enzymes involved in numerous cellular processes, yet little is known about the impact of iron deficiency on cellular metabolism or iron proteins. Previous studies have focused on changes in transcript and proteins levels in iron-deficient cells, yet these changes may not reflect changes in transport activity or flux through a metabolic pathway. We analyzed the metabolomes and transcriptomes of yeast grown in iron-rich and iron-poor media to determine which biosynthetic processes are altered when iron availability falls. Iron deficiency led to changes in glucose metabolism, amino acid biosynthesis, and lipid biosynthesis that were due to deficiencies in specific iron-dependent enzymes. Iron-sulfur proteins exhibited loss of iron cofactors, yet amino acid synthesis was maintained. Ergosterol and sphingolipid biosynthetic pathways had blocks at points where heme and diiron enzymes function, whereas Ole1, the essential fatty acid desaturase, was resistant to iron depletion. Iron-deficient cells exhibited depletion of most iron enzyme activities, but loss of activity during iron deficiency did not consistently disrupt metabolism. Amino acid homeostasis was robust, but iron deficiency impaired lipid synthesis, altering the properties and functions of cellular membranes.

| S-EPMC2863190 | biostudies-literature

PIASy mediates SUMO-2 conjugation of Topoisomerase-II on mitotic chromosomes.

Project description:Here we show that the PIASy protein is specifically required for mitotic modification of Topoisomerase-II by SUMO-2 conjugation in Xenopus egg extracts. PIASy was unique among the PIAS family members in its capacity to bind mitotic chromosomes and recruit Ubc9 onto chromatin. These properties were essential, since PIASy mutants that did not bind chromatin or failed to recruit Ubc9 were functionally inactive. We observed that PIASy depletion eliminated essentially all chromosomal accumulation of EGFP-SUMO-2-conjugated species, suggesting that it is the primary E3-like factor for mitotic chromosomal substrates of SUMO-2. PIASy-dependent SUMO-2-conjugated species were highly concentrated on the inner centromere, and inhibition of PIASy blocked anaphase sister chromatid segregation in egg extracts. Taken together, our observations suggest that PIASy is a critical regulator of mitotic SUMO-2 conjugation for Topoisomerase-II and other chromosomal substrates, and that its activity may have particular relevance for centromeric functions required for proper chromosome segregation.

| S-EPMC1150894 | biostudies-literature

Comprehensive Temporal Protein Dynamics during the Diauxic Shift in Saccharomyces cerevisiae.

Project description:Yeast (Saccharomyces cerevisiae) has served as a key model system in biology and as a benchmark for "omics" technology. Although near-complete proteomes of log phase yeast have been measured, protein abundance in yeast is dynamic, particularly during the transition from log to stationary phase. Defining the dynamics of proteomic changes during this transition, termed the diauxic shift, is important to understand the basic biology of proliferative versus quiescent cells. Here, we perform temporal quantitative proteomics to fully capture protein induction and repression during the diauxic shift. Accurate and sensitive quantitation at a high temporal resolution and depth of proteome coverage was achieved using TMT10 reagents and LC-MS3 analysis on an Orbitrap Fusion tribrid mass spectrometer deploying synchronous precursor selection. Triplicate experiments were analyzed using the time-course R package and a simple template matching strategy was used to reveal groups of proteins with similar temporal patterns of protein induction and repression. Within these groups are functionally distinct types of proteins such as those of glyoxylate metabolism and many proteins of unknown function not previously associated with the diauxic shift (e.g. YNR034W-A and FMP16). We also perform a dual time-course experiment to determine Hap2-dependent proteins during the diauxic shift. These data serve as an important basic model for fermentative versus respiratory growth of yeast and other eukaryotes and are a benchmark for temporal quantitative proteomics.

| S-EPMC4563728 | biostudies-literature

Ribosome deficiency protects against ER stress in Saccharomyces cerevisiae.

Project description:In Saccharomyces cerevisiae, 59 of the 78 ribosomal proteins are encoded by duplicated genes that, in most cases, encode identical or very similar protein products. However, different sets of ribosomal protein genes have been identified in screens for various phenotypes, including life span, budding pattern, and drug sensitivities. Due to potential suppressors of growth rate defects among this set of strains in the ORF deletion collection, we regenerated the entire set of haploid ribosomal protein gene deletion strains in a clean genetic background. The new strains were used to create double deletions lacking both paralogs, allowing us to define a set of 14 nonessential ribosomal proteins. Replicative life-span analysis of new strains corresponding to ORF deletion collection strains that likely carried suppressors of growth defects identified 11 new yeast replicative aging genes. Treatment of the collection of ribosomal protein gene deletion strains with tunicamycin revealed a significant correlation between slow growth and resistance to ER stress that was recapitulated by reducing translation of wild-type yeast with cycloheximide. Interestingly, enhanced tunicamycin resistance in ribosomal protein gene deletion mutants was independent of the unfolded protein response transcription factor Hac1. These data support a model in which reduced translation is protective against ER stress by a mechanism distinct from the canonical ER stress response pathway and further add to the diverse yet specific phenotypes associated with ribosomal protein gene deletions.

| S-EPMC3338253 | biostudies-literature

A comprehensive gene regulatory network for the diauxic shift in Saccharomyces cerevisiae.

Project description:Existing machine-readable resources for large-scale gene regulatory networks usually do not provide context information characterizing the activating conditions for a regulation and how targeted genes are affected. Although this information is essentially required for data interpretation, available networks are often restricted to not condition-dependent, non-quantitative, plain binary interactions as derived from high-throughput screens. In this article, we present a comprehensive Petri net based regulatory network that controls the diauxic shift in Saccharomyces cerevisiae. For 100 specific enzymatic genes, we collected regulations from public databases as well as identified and manually curated >400 relevant scientific articles. The resulting network consists of >300 multi-input regulatory interactions providing (i) activating conditions for the regulators; (ii) semi-quantitative effects on their targets; and (iii) classification of the experimental evidence. The diauxic shift network compiles widespread distributed regulatory information and is available in an easy-to-use machine-readable form. Additionally, we developed a browsable system organizing the network into pathway maps, which allows to inspect and trace the evidence for each annotated regulation in the model.

| S-EPMC3794591 | biostudies-literature

Compromised RNA polymerase III complex assembly leads to local alterations of intergenic RNA polymerase II transcription in Saccharomyces cerevisiae.

Project description:BackgroundAssembled RNA polymerase III (Pol III) complexes exert local effects on chromatin processes, including influencing transcription of neighboring RNA polymerase II (Pol II) transcribed genes. These properties have been designated as 'extra-transcriptional' effects of the Pol III complex. Previous coding sequence microarray studies using Pol III factor mutants to determine global effects of Pol III complex assembly on Pol II promoter activity revealed only modest effects that did not correlate with the proximity of Pol III complex binding sites.ResultsGiven our recent results demonstrating that tDNAs block progression of intergenic Pol II transcription, we hypothesized that extra-transcriptional effects within intergenic regions were not identified in the microarray study. To reconsider global impacts of Pol III complex binding, we used RNA sequencing to compare transcriptomes of wild type versus Pol III transcription factor TFIIIC depleted mutants. The results reveal altered intergenic Pol II transcription near TFIIIC binding sites in the mutant strains, where we observe readthrough of upstream transcripts that normally terminate near these sites, 5'- and 3'-extended transcripts, and de-repression of adjacent genes and intergenic regions.ConclusionsThe results suggest that effects of assembled Pol III complexes on transcription of neighboring Pol II promoters are of greater magnitude than previously appreciated, that such effects influence expression of adjacent genes at transcriptional start site and translational levels, and may explain a function of the conserved ETC sites in yeast. The results may also be relevant to synthetic biology efforts to design a minimal yeast genome.

| S-EPMC4228148 | biostudies-literature

Structural analysis of Wss1 protein from saccharomyces cerevisiae.

Project description:Wss1 is a DNA-protein crosslinks (DPCs) repair protein, which is responsible for degradation of the protein components in DPCs. In this investigation, crystal structure of the protease domain from saccharomyces cerevisiae Wss1 (ScWss1) was solved and was compared with the known crystal structure of Schizosaccharomyces prombe Wss1 (SpWss1). It is found that the cleft near zinc ion to be the most conserved core region of Wss1 and that the electronic surface distributions vary greatly between the two homologs. Solution architecture of the full-length ScWss1 was further investigated by small-angle X-ray scattering (SAXS), which indicated the protein contains a flexible region inside. Finally, based on the structural information, a mechanism was proposed about how the enzyme is activated by DNA substrates.

| S-EPMC5557861 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data