A fast-acting lipid checkpoint in G1 prevents mitotic defects
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE254479 | GEO | 2024/02/22
REPOSITORIES: GEO
Similar Datasets
Project description:Cell cycle sensing of oxidative stress in Saccharomyces cerevisiae by oxidation of a specific cysteine residue in the transcription factor Swi6p. Yeast cells begin to bud and enter S phase when growth conditions are favourable during G1 phase. When subjected to oxidative stress, cells arrest at G1 delaying entry into the cell cycle allowing repair of cellular damage. Hence, oxidative stress sensing is coordinated with the regulation of cell cycle. We identified a redox sensing cysteine residue in the cell-cycle regulator of Saccharomyces cerevisiae, Swi6p, at position 404. Mutation of Cys404 to alanine abolished the ability of the cells to arrest at G1 upon treatment by lipid hydroperoxide. By constructing a truncated form of Swi6p, the Cys404 residue was found to be oxidised when cells were subjected to the oxidant. Furthermore, microarray analysis revealed that mutation of Cys404 to alanine led to loss of suppression of G1-cyclins CLN1 and PCL1 when the cells were exposed to lipid hydroperoxide. In conclusion, oxidation of Cys404 serves as a molecular sensor of oxidative stress and inhibits entry into the cell cycle by suppression of G1-cyclin expression.
2011-01-31 | GSE18334 | GEO
Project description:Cell cycle sensing of oxidative stress in Saccharomyces cerevisiae by oxidation of a specific cysteine residue in the transcription factor Swi6p. Yeast cells begin to bud and enter S phase when growth conditions are favourable during G1 phase. When subjected to oxidative stress, cells arrest at G1 delaying entry into the cell cycle allowing repair of cellular damage. Hence, oxidative stress sensing is coordinated with the regulation of cell cycle. We identified a redox sensing cysteine residue in the cell-cycle regulator of Saccharomyces cerevisiae, Swi6p, at position 404. Mutation of Cys404 to alanine abolished the ability of the cells to arrest at G1 upon treatment by lipid hydroperoxide. By constructing a truncated form of Swi6p, the Cys404 residue was found to be oxidised when cells were subjected to the oxidant. Furthermore, microarray analysis revealed that mutation of Cys404 to alanine led to loss of suppression of G1-cyclins CLN1 and PCL1 when the cells were exposed to lipid hydroperoxide. In conclusion, oxidation of Cys404 serves as a molecular sensor of oxidative stress and inhibits entry into the cell cycle by suppression of G1-cyclin expression. We used a gene expression approach to assess the involvement of Cys404 in oxidative stress by mutating this residue to alanine in order to study whether it contributes to Swi6p, a transcriptional factor, function for redox regulation of the cell cycle. Wild type, swi6-deletant, and swi6 C404A-mutated yeast cells were treated with either linoleic acid hydroperoxide (LoaOOH) or control. Three replicates per group/treatment.
2011-01-31 | E-GEOD-18334 | biostudies-arrayexpress
Project description:Not many models of mammalian cell cycle system exist due to its complexity. Some models are too complex and hard to understand, while some others are too simple and not comprehensive enough. Moreover, some essential aspects, such as the response of G1-S and G2-M checkpoints to DNA damage as well as the growth factor signalling, have not been investigated from a systems point of view in current mammalian cell cycle models. To address these issues, we bring a holistic perspective to cell cycle by mathematically modelling it as a complex system consisting of important sub-systems that interact with each other. This retains the functionality of the system and provides a clearer interpretation to the processes within it while reducing the complexity in comprehending these processes. To achieve this, we first update a published ODE mathematical model of cell cycle with current knowledge. Then the part of the mathematical model relevant to each sub-system is shown separately in conjunction with a diagram of the sub-system as part of this representation. The model sub-systems are Growth Factor, DNA damage, G1-S, and G2-M checkpoint signalling. To further simplify the model and better explore the function of sub-systems, they are further divided into modules. Here we also add important new modules of: chk-related rapid cell cycle arrest, p53 modules expanded to seamlessly integrate with the rapid arrest module, Tyrosine phosphatase modules that activate Cyc_Cdk complexes and play a crucial role in rapid and delay arrest at both G1-S and G2-M, Tyrosine Kinase module that is important for inactivating nuclear transport of CycB_cdk1 through Wee1 to resist M phase entry, Plk1-Related module that is crucial in activating Tyrosine phosphatases and inactivating Tyrosine kinase, and APC-Related module to show steps in CycB degradation. This multi-level systems approach incorporating all known aspects of cell cycle allowed us to (i) study, through dynamic simulation of an ODE model, comprehensive details of cell cycle dynamics under normal and DNA damage conditions revealing the role and value of the added new modules and elements, (ii) assess, through a global sensitivity analysis, the most influential sub-systems, modules and parameters on system response, such as G1-S and G2-M transitions, and (iii) probe deeply into the relationship between DNA damage and cell cycle progression and test the biological evidence that G1-S is relatively inefficient in arresting damaged cells compared to G2-M checkpoint. To perform sensitivity analysis, Self-Organizing Map with Correlation Coefficient Analysis (SOMCCA) is developed which shows that Growth Factor and G1-S Checkpoint sub-systems and 13 parameters in the modules within them are crucial for G1-S and G2-M transitions. To study the relative efficiency of DNA damage checkpoints, a Checkpoint Efficiency Evaluator (CEE) is developed based on perturbation studies and statistical Type II error. Accordingly, cell cycle is about 96% efficient in arresting damaged cells with G2-M checkpoint being more efficient than G1-S. Further, both checkpoint systems are near perfect (98.6%) in passing healthy cells. Thus this study has shown the efficacy of the proposed systems approach to gain a better understanding of different aspects of mammalian cell cycle system separately and as an integrated system that will also be useful in investigating targeted therapy in future cancer treatments.
2018-12-13 | MODEL1812130001 | BioModels
Project description:The retinoblastoma (Rb) protein is a potent tumor suppressor which is known to negatively regulate the cell cycle as well as tumor progression. Phosphorylated Rb protein (pRb) has been demonstrated to be in-charge for the key G1 checkpoint, blocking entry into S-phase and thereby the cell growth. This study was designed to capture interacting protein partners of Rb1 as the cell cycle progresses. Rb1 expressing HEK-293 cells were cultured in light, medium and heavy SILAC labels to capture the changes in Rb1 interactome as the cell cycle progressed from G0 to G1S and then to G2 phase, respectively. This data might help in understanding the cell cycle regulatory effect of Rb1 protein and complement the available information on its interacting partners.
2017-09-14 | PXD007708 | Pride
Project description:Coordination of cell cycle progression with central metabolism is fundamental to all cell types and likely underlies differentiation into dispersal cells in bacteria. How central metabolism is monitored to regulate cell cycle functions is poorly understood. A forward genetic selection for cell cycle regulators in the polarized alpha-proteobacterium Caulobacter crescentus unearthed the uncharacterized CitA citrate synthase, a TCA (tricarboxylic acid) cycle enzyme, as unprecedented checkpoint regulator of the G1→S transition. We show that loss of the CitA protein provokes a (p)ppGpp alarmone-dependent G1-phase arrest without apparent metabolic or energy insufficiency. While S-phase entry is still conferred when CitA is rendered catalytically inactive, the paralogous CitB citrate synthase has no overt role other than sustaining TCA cycle activity when CitA is absent. With eukaryotic citrate synthase paralogs known to fulfill regulatory functions, our work extends the moonlighting paradigm to citrate synthase coordinating central (TCA) metabolism with development and perhaps antibiotic tolerance in bacteria.
2020-03-19 | GSE144533 | GEO
Project description:Genomic aberrations of Cyclin D1 (CCND1) and CDK4 in neuroblastoma indicate that dysregulation of the G1 entry checkpoint is an important cell cycle aberration in this pediatric tumor. Here we report that analysis of Affymetrix expression data of primary neuroblastic tumors shows an extensive over-expression of Cyclin D1 and CDK4 which correlates with histological subgroups and prognosis respectively. Immunohistochemical analysis demonstrated an over-expression of Cyclin D1 in neuroblasts and a low Cyclin D1 expression in all cell types in ganglioneuroma. This suggests an involvement of G1 regulating genes in neuronal differentiation processes which we further evaluated using RNA interference against Cyclin D1 and its kinase partner CDK4 in several neuroblastoma cell lines. This resulted in pRb pathway inhibition as shown by an almost complete disappearance of CDK4 specific pRb phosphorylation; reduction of E2F transcriptional activity and a decrease of Cyclin A protein levels. The Cyclin D1 and CDK4 knock-down resulted in a significant reduction in cell proliferation, a G1 specific cell cycle arrest and moreover an extensive neuronal differentiation. Affymetrix microarray profiling of siRNA treated cells revealed a shift in expression profile towards a neuronal phenotype. Several new potential downstream players are identified. We conclude that neuroblastoma functionally depend on over-expression of G1 regulating genes to maintain their undifferentiated phenotype. Experiment Overall Design: The Cell line IMR-32 at time point 0 and transiently transfected with siRNA against GFP, Cyclin D1 and CDK4 at time point 48 hours. All experiments are biological triplicates.
2008-10-25 | E-GEOD-8866 | biostudies-arrayexpress
Project description:MBF and SBF transcription factors regulate a large family of coordinately expressed G1/S genes required for early cell cycle functions including DNA replication and repair. SBF is inactivated upon S phase entry by Clb/CDK whereas MBF targets are repressed by the corepressor, Nrm1. Using genome-wide expression analysis, we show that genotoxic stress during S phase specifically induces MBF-regulated genes via direct phosphorylation of Nrm1 by Rad53, the effector checkpoint kinase, and prevents its binding to MBF target promoters. Interestingly, some previously defined targets of SBF, including Swe1, are activated by replication stress. Swe1 undergoes a transcription factor exchange leading to its repression by Nrm1/MBF, which renders it sensitive to derepression by the S phase checkpoint. We conclude that MBF-regulated genes are distinguished from SBF-regulated genes by their sensitivity to activation by the S phase checkpoint, thereby, providing an effective mechanism for enhancing DNA replication and repair and promoting genome stability. Modified Loop Time-series design, time points at 0, 30, 45, 60 and 75 minutes. Conditions are untreated (UT), methyl methane sulfonate (MMS-0.033%), camptothecin (CPT-50uM), and hydroxyurea (HU-0.2M)
2012-02-15 | E-GEOD-33695 | biostudies-arrayexpress
Project description:Defects in DNA damage responses may underlie genetic instability and malignant progression in melanoma. Cultures of normal human melanocytes (NHMs) and melanoma lines were analyzed to determine whether global patterns of gene expression could predict the efficacy of DNA damage cell cycle checkpoints that arrest growth and suppress genetic instability. NHMs displayed effective G1 and G2 checkpoint responses to ionizing radiation-induced DNA damage. A majority of melanoma cell lines (11/16) displayed significant quantitative defects in one or both checkpoints. Melanomas with B-RAF mutations as a class displayed a significant defect in DNA damage G2 checkpoint function. In contrast the epithelial-like subtype of melanomas with wildtype N-RAS and B-RAF alleles displayed an effective G2 checkpoint but a significant defect in G1 checkpoint function. RNA expression profiling revealed that melanoma lines with defects in the DNA damage G1 checkpoint displayed reduced expression of p53 transcriptional targets, such as CDKN1A and DDB2, and enhanced expression of proliferation-associated genes, such as CDC7 and GEMININ. A Bayesian analysis tool was more accurate than significance analysis of microarrays for predicting checkpoint function using a leave-one-out method. The results suggest that defects in DNA damage checkpoints may be recognized in melanomas through analysis of gene expression. Experiment Overall Design: Normal human melanocyte and melanoma cell lines w/wo mutations in B-raf or N-ras were treated with 1.5 Gy IR irridiartion for G1 and G2 checkpoint determination. RNA was isolated from exponentially growing cultures and applied for microarray hybridizaton with Agilent 44 K (G4112A) array.
2008-06-15 | E-GEOD-7469 | biostudies-arrayexpress
Project description:The ERK family of MAP kinase plays a critical role in growth factor-stimulated cell cycle progression from G0/G1 to S phase. But, how sustained activation of ERK promotes G1 progression has remained unclear. Here, our systematic analysis on the temporal program of ERK-dependent gene expression shows that sustained activation of ERK is required for induction and maintenance of the decreased expression levels of a set of genes. Moreover, our cell biological analysis reveals that these ERK-dependent downregulated genes have the ability to block S phase entry. Cessation of ERK activation at mid or late G1 leads to a rapid increase of these anti-proliferative genes and results in the inhibition of S phase entry. These findings uncover an important mechanism by which the duration of ERK activation regulates cell cycle progression through dynamic changes in gene expression, and identify novel ERK target genes crucial for the regulation of cell cycle progression.
2007-11-24 | E-GEOD-4739 | biostudies-arrayexpress
Project description:Biosynthesis scales with cell size such that protein concentrations generally remain constant as cells grow. As an exception, synthesis of the cell-cycle inhibitor Whi5 ‘sub-scales’ with cell size so that its concentration is lower in larger cells to promote cell-cycle entry. Here, we find that a transcriptional control uncouples Whi5 synthesis from cell size and, screening for similar genes, identify histones as the major class of sub-scaling transcripts besides WHI5. Histone synthesis is thereby matched to genome content rather than cell size. Such sub-scaling proteins are challenged by asymmetric cell division because proteins are typically partitioned in proportion to new-born cell volume. To avoid this fate, Whi5 uses chromatin-binding to partition similar protein amounts to each new-born cell regardless of cell size. Finally, disrupting both Whi5 synthesis and chromatin-based partitioning compromises G1 size control. Thus, specific transcriptional and partitioning mechanisms determine protein sub-scaling to control cell size.
2021-12-01 | GSE167842 | GEO