scholarly journals Requirement for TAFII250 Acetyltransferase Activity in Cell Cycle Progression

2000 ◽  
Vol 20 (4) ◽  
pp. 1134-1139 ◽  
Author(s):  
Elizabeth L. Dunphy ◽  
Theron Johnson ◽  
Scott S. Auerbach ◽  
Edith H. Wang
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Temperature Sensitive ◽  
Cycle Progression ◽  
Acetyltransferase Activity ◽  
Cycle Arrest ◽  
Protein Encoding ◽  
Acetyltransferase Domain ◽  
Mutant Cells

ABSTRACT The TATA-binding protein (TBP)-associated factor TAFII250 is the largest component of the basal transcription factor IID (TFIID). A missense mutation that maps to the acetyltransferase domain of TAFII250 induces the temperature-sensitive (ts) mutant hamster cell lines ts13 and tsBN462 to arrest in late G1. At the nonpermissive temperature (39.5°C), transcription from only a subset of protein encoding genes, including the G1 cyclins, is dramatically reduced in the mutant cells. Here we demonstrate that the ability of the ts13 allele of TAFII250 to acetylate histones in vitro is temperature sensitive suggesting that this enzymatic activity is compromised at 39.5°C in the mutant cells. Mutagenesis of a putative acetyl coenzyme A binding site produced a TAFII250 protein that displayed significantly reduced histone acetyltransferase activity but retained TBP and TAFII150 binding. Expression of this mutant in ts13 cells was unable to complement the cell cycle arrest or transcriptional defect observed at 39.5°C. These data suggest that TAFII250 acetyltransferase activity is required for cell cycle progression and regulates the expression of essential proliferative control genes.

scholarly journals PHF2 histone demethylase prevents DNA damage and genome instability by controlling cell cycle progression of neural progenitors

2019 ◽  
Vol 116 (39) ◽  
pp. 19464-19473 ◽  
Author(s):  
Stella Pappa ◽  
Natalia Padilla ◽  
Simona Iacobucci ◽  
Marta Vicioso ◽  
Elena Álvarez de la Campa ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Genome Stability ◽  
Cell Cycle Progression ◽  
Genome Instability ◽  
Neural Progenitors ◽  
Cycle Progression ◽  
Cycle Arrest ◽  
Biochemical Assays

Histone H3 lysine 9 methylation (H3K9me) is essential for cellular homeostasis; however, its contribution to development is not well established. Here, we demonstrate that the H3K9me2 demethylase PHF2 is essential for neural progenitor proliferation in vitro and for early neurogenesis in the chicken spinal cord. Using genome-wide analyses and biochemical assays we show that PHF2 controls the expression of critical cell cycle progression genes, particularly those related to DNA replication, by keeping low levels of H3K9me3 at promoters. Accordingly, PHF2 depletion induces R-loop accumulation that leads to extensive DNA damage and cell cycle arrest. These data reveal a role of PHF2 as a guarantor of genome stability that allows proper expansion of neural progenitors during development.

scholarly journals A Novel Interaction of Ecdysoneless (ECD) Protein with R2TP Complex Component RUVBL1 Is Required for the Functional Role of ECD in Cell Cycle Progression

2015 ◽  
Vol 36 (6) ◽  
pp. 886-899 ◽  
Author(s):  
Riyaz A. Mir ◽  
Aditya Bele ◽  
Sameer Mirza ◽  
Shashank Srivastava ◽  
Appolinaire A. Olou ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Protein Interactions ◽  
Cell Cycle Progression ◽  
Germ Line ◽  
Regulatory Function ◽  
Cycle Progression ◽  
Cycle Arrest

Ecdysoneless (ECD) is an evolutionarily conserved protein whose germ line deletion is embryonic lethal. Deletion ofEcdin cells causes cell cycle arrest, which is rescued by exogenousECD, demonstrating a requirement ofECDfor normal mammalian cell cycle progression. However, the exact mechanism by which ECD regulates cell cycle is unknown. Here, we demonstrate that ECD protein levels and subcellular localization are invariant during cell cycle progression, suggesting a potential role of posttranslational modifications or protein-protein interactions. Since phosphorylated ECD was recently shown to interact with the PIH1D1 adaptor component of the R2TP cochaperone complex, we examined the requirement of ECD phosphorylation in cell cycle progression. Notably, phosphorylation-deficient ECD mutants that failed to bind to PIH1D1in vitrofully retained the ability to interact with the R2TP complex and yet exhibited a reduced ability to rescueEcd-deficient cells from cell cycle arrest. Biochemical analyses demonstrated an additional phosphorylation-independent interaction of ECD with the RUVBL1 component of the R2TP complex, and this interaction is essential for ECD's cell cycle progression function. These studies demonstrate that interaction of ECD with RUVBL1, and its CK2-mediated phosphorylation, independent of its interaction with PIH1D1, are important for its cell cycle regulatory function.

scholarly journals Cell Cycle Arrest and Autophagy Induced by Compound Kushen Injection in sw620 and sw480 Colorectal Cancer Cells with p53 Mutation

2019 ◽  
Author(s):  
Jie Sun ◽  
Di Wang ◽  
Yu Zhang ◽  
Qing Mu ◽  
Mei Li ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Cell Cycle ◽  
Cancer Cells ◽  
Cell Cycle Progression ◽  
Mutant P53 ◽  
Cycle Progression ◽  
Cycle Arrest ◽  
Colorectal Cancer Cells

Abstract Background Compound Kushen Injection (CKI) has been clinically used in China for 15 years to treat various types of solid tumors, including colorectal cancer. Here we examine cell cycle arrest, induced autophagy, and mutant p53 pathways perturbed by CKI in colorectal cancer cells. We and other groups have shown that CKI alters p53 gene expression patterns and suppresses proliferation in colorectal cancer cells. Methods We measured the effect of CKI on cell proliferation, cell cycle progression and autophagy in sw480 and sw620 colorectal cancer cells in vitro, and carcinogenesis and the progression of azoxymethane/dextran sodium sulfate-induced colorectal cancer in ICR mice in vivo. We also used RNA sequencing to analyze mRNA expression altered by CKI, and further validated the expression of mutant p53 and several genes in the cell cycle pathway using reverse transcriptase-quantitative PCR and western blotting. Using network pharmacology (BATMAN-TCM database), we have also predicted the active ingredients in CKI involved in regulating the expression of mutant p53. Results We show evidence that CKI significantly suppressed proliferation and cell cycle progression, and induced autophagy of sw480 and sw620 cells in vitro; it also inhibited the development of inflammatory colorectal cancer in vivo. We also show that the down-regulated expression of mutant p53 and adjustments in several key genes related closely to cell-cycle progression. Furthermore, N-oxysophocarpine, lupenone, and geranylacetone were predicted to be the active ingredients of CKI involved in the down-regulated expression of mutant p53. Conclusion Our results indicate that CKI likely acts as a potential anti-cancer therapeutic agent that targets the cell cycle pathway, suggesting a key role in the development of a novel subsidiary therapeutic approach against mutant p53 in patients with colorectal cancer.

scholarly journals The G(2) DNA damage checkpoint targets both Wee1 and Cdc25

2000 ◽  
Vol 113 (10) ◽  
pp. 1727-1736 ◽  
Author(s):  
J.M. Raleigh ◽  
M.J. O'Connell
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Cell Cycle Progression ◽  
Dna Damage Checkpoint ◽  
Checkpoint Control ◽  
Down Regulation ◽  
Cycle Progression ◽  
Cycle Arrest ◽  
Checkpoint Pathway

The onset of mitosis is controlled by the cyclin dependent kinase Cdc2p. Cdc2p activity is controlled through the balance of phosphorylation and dephosphorylation of tyrosine-15 (Y15) by the Wee1p kinase and Cdc25p phosphatase. In the fission yeast Schizosaccharomyces pombe, detection of DNA damage in G(2) activates a checkpoint that prevents entry into mitosis through the maintenance of Y15 phosphorylation of Cdc2p, thus ensuring DNA repair precedes chromosome segregation. The protein kinase Chk1p is the endpoint of this checkpoint pathway. We have previously reported that overexpression of Chk1p causes a wee1(+)-dependent G(2) arrest, and this or irradiation leads to hyperphosphorylation of Wee1p. Moreover, Chk1p directly phosphorylates Wee1p in vitro. These data suggested that Wee1p is a key target of Chk1p action in checkpoint control. However, cells lacking wee1(+) are checkpoint proficient and sustained Chk1p overexpression arrests cell cycle progression independently of Wee1p. Therefore, up-regulation of Wee1p alone cannot enforce a checkpoint arrest. Chk1p can also phosphorylate Cdc25p in vitro. These phosphorylation events are thought to promote the interaction with 14–3-3 proteins the cytoplasmic retention of the 14–3-3/Cdc25p complexes. However, we show here that the G(2) DNA damage checkpoint is intact in cells that regulate mitotic entry independently of Cdc25p. Further, these cells are still sensitive to Chk1p-mediated arrest, and so down-regulation of Cdc25p is also insufficient to regulate checkpoint arrest. Conversely, inactivation of both wee1(+) and cdc25(+)abolishes checkpoint control. We also show that activation of the G(2) DNA damage checkpoint induces a transient increase in Wee1p levels. We conclude that the G(2) DNA damage checkpoint simultaneously signals via both up-regulation of Wee1p and down-regulation of Cdc25p, thus providing a double-lock mechanism to ensure cell cycle arrest and genomic stability.

scholarly journals The Cytotoxicity and Genotoxicity of Three Dental Universal Adhesives—An In Vitro Study

2020 ◽  
Vol 21 (11) ◽  
pp. 3950 ◽  
Author(s):  
Adam Wawrzynkiewicz ◽  
Wioletta Rozpedek-Kaminska ◽  
Grzegorz Galita ◽  
Monika Lukomska-Szymanska ◽  
Barbara Lapinska ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Line ◽  
Cell Cycle Progression ◽  
Annexin V ◽  
In Vitro Study ◽  
Xtt Assay ◽  
Cycle Progression ◽  
Cycle Arrest ◽  
Universal Adhesives

Dental universal adhesives are considered an useful tool in modern dentistry as they can be used in different etching techniques, allow for simplified protocol and provide sufficient bond strength. However, there is still no consensus as to their toxicity towards pulp. Thus, the present study aimed to evaluate the cytotoxicity and genotoxicity of three universal adhesives: OptiBond Universal, Prime&Bond Universal and Adhese in an in vitro experimental model, monocyte/macrophage cell line SC (ATCC CRL-9855). The cytotoxicity was measured by means of XTT assay, whereas the genotoxicity (comet assay) was evaluated based on the percentage of DNA present in the comet tail. Furthermore, the ability of the adhesives to induce apoptosis was analyzed using flow cytometry (FC) with the FITC annexin V/propidium iodide (PI) double staining. The analysis of the cell cycle progression was performed with FC using PI staining. OptiBond Universal presented significant, while Prime&Bond Universal and Adhese Universal had minimal cytotoxicity and genotoxicity towards human SC cells. Moreover, only OptiBond Universal increased the level of apoptosis in SC cell line. None of the adhesives showed significant cell cycle arrest, as revealed by FC analysis. Due to substantial differences in toxicity in in vitro studies of dental adhesives, there is a great need for further research in order to establish more reliable test protocols allowing for standardized methodology.

scholarly journals Wobble Inosine tRNA Modification Is Essential to Cell Cycle Progression in G1/S and G2/M Transitions in Fission Yeast

2007 ◽  
Vol 282 (46) ◽  
pp. 33459-33465 ◽  
Author(s):  
Satoshi Tsutsumi ◽  
Reiko Sugiura ◽  
Yan Ma ◽  
Hideki Tokuoka ◽  
Kazuki Ohta ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Fission Yeast ◽  
Cell Cycle Progression ◽  
Budding Yeast ◽  
Temperature Sensitive ◽  
Trna Modification ◽  
Gene Encoding ◽  
Cycle Progression ◽  
Catalytically Active ◽  
Mutant Cells

Inosine (I) at position 34 (wobble position) of tRNA is formed by the hydrolytic deamination of a genomically encoded adenosine (A). The enzyme catalyzing this reaction, termed tRNA A:34 deaminase, is the heterodimeric Tad2p/ADAT2·Tad3p/ADAT3 complex in eukaryotes. In budding yeast, deletion of each subunit is lethal, indicating that the wobble inosine tRNA modification is essential for viability; however, most of its physiological roles remain unknown. To identify novel cell cycle mutants in fission yeast, we isolated the tad3-1 mutant that is allelic to the tad3+ gene encoding a homolog of budding yeast Tad3p. Interestingly, the tad3-1 mutant cells principally exhibited cell cycle-specific phenotype, namely temperature-sensitive and irreversible cell cycle arrest both in G1 and G2. Further analyses revealed that in the tad3-1 mutant cells, the S257N mutation that occurred in the catalytically inactive Tad3 subunit affected its association with catalytically active Tad2 subunit, leading to an impairment in the A to I conversion at position 34 of tRNA. In tad3-1 mutant cells, the overexpression of the tad3+ gene completely suppressed the decreased tRNA inosine content. Notably, the overexpression of the tad2+ gene partially suppressed the temperature-sensitive phenotype and the decreased tRNA inosine content, indicating that the tad3-1 mutant phenotype is because of the insufficient I34 formation of tRNA. These results suggest that the wobble inosine tRNA modification is essential for cell cycle progression in the G1/S and G2/M transitions in fission yeast.

scholarly journals Activation of the Bur1-Bur2 Cyclin-Dependent Kinase Complex by Cak1

2002 ◽  
Vol 22 (19) ◽  
pp. 6750-6758 ◽  
Author(s):  
Sheng Yao ◽  
Gregory Prelich
Keyword(s):  
Cell Cycle ◽  
Rna Polymerase Ii ◽  
Cell Cycle Progression ◽  
Single Gene ◽  
Eukaryotic Cell ◽  
Temperature Sensitive ◽  
Cycle Progression ◽  
Carboxy Terminal

ABSTRACT Cyclin-dependent kinases (Cdks) were originally identified as regulators of eukaryotic cell cycle progression, but several Cdks were subsequently shown to perform important roles as transcriptional regulators. While the mechanisms regulating the Cdks involved in cell cycle progression are well documented, much less is known regarding how the Cdks that are involved in transcription are regulated. In Saccharomyces cerevisiae, Bur1 and Bur2 comprise a Cdk complex that is involved in transcriptional regulation, presumably mediated by its phosphorylation of the carboxy-terminal domain (CTD) of the largest subunit of RNA polymerase II. To investigate the regulation of Bur1 in vivo, we searched for high-copy-number suppressors of a bur1 temperature-sensitive mutation, identifying a single gene, CAK1. Cak1 is known to activate two other Cdks in yeast by phosphorylating a threonine within their conserved T-loop domains. Bur1 also has the conserved threonine within its T loop and is therefore a potential direct target of Cak1. Additional tests establish a direct functional interaction between Cak1 and the Bur1-Bur2 Cdk complex: Bur1 is phosphorylated in vivo, both the conserved Bur1 T-loop threonine and Cak1 are required for phosphorylation and Bur1 function in vivo, and recombinant Cak1 stimulates CTD kinase activity of the purified Bur1-Bur2 complex in vitro. Thus, both genetic and biochemical evidence demonstrate that Cak1 is a physiological regulator of the Bur1 kinase.

scholarly journals Esa1p Is an Essential Histone Acetyltransferase Required for Cell Cycle Progression

1999 ◽  
Vol 19 (4) ◽  
pp. 2515-2526 ◽  
Author(s):  
Astrid S. Clarke ◽  
Joanna E. Lowell ◽  
Sandra J. Jacobson ◽  
Lorraine Pillus
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Histone Acetyltransferase ◽  
Essential Gene ◽  
Cell Cycle Control ◽  
Biological Significance ◽  
Temperature Sensitive ◽  
Cycle Progression

ABSTRACT Histones are dynamically modified during chromatin assembly, as specific transcriptional patterns are established, and during mitosis and development. Modifications include acetylation, phosphorylation, ubiquitination, methylation, and ADP-ribosylation, but the biological significance of each of these is not well understood. For example, distinct acetylation patterns correlate with nucleosome formation and with transcriptionally activated or silenced chromatin, yet mutations in genes encoding several yeast histone acetyltransferase (HAT) activities result in either no cellular phenotype or only modest growth defects. Here we report characterization of ESA1, an essential gene that is a member of the MYST family that includes two yeast silencing genes, human genes associated with leukemia and with the human immunodeficiency virus type 1 Tat protein, and Drosophila mof, a gene essential for male dosage compensation. Esa1p acetylates histones in a pattern distinct from those of other yeast enzymes, and temperature-sensitive mutant alleles abolish enzymatic activity in vitro and result in partial loss of an acetylated isoform of histone H4 in vivo. Strains carrying these mutations are also blocked in the cell cycle such that at restrictive temperatures,esa1 mutants succeed in replicating their DNA but fail to proceed normally through mitosis and cytokinesis. Recent studies show that Esa1p enhances transcription in vitro and thus may modulate expression of genes important for cell cycle control. These observations therefore link an essential HAT activity to cell cycle progression, potentially through discrete transcriptional regulatory events.

scholarly journals LMNB2 promotes the progression of colorectal cancer by silencing p21 expression

2021 ◽  
Vol 12 (4) ◽  
Author(s):  
Chen-Hua Dong ◽  
Tao Jiang ◽  
Hang Yin ◽  
Hu Song ◽  
Yi Zhang ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Cell Cycle ◽  
Cell Proliferation ◽  
Cell Cycle Progression ◽  
Molecular Mechanisms ◽  
Gene Set Enrichment Analysis ◽  
Molecular Therapy ◽  
Cycle Progression ◽  
Cancer Tissues

AbstractColorectal cancer is the second common cause of death worldwide. Lamin B2 (LMNB2) is involved in chromatin remodeling and the rupture and reorganization of nuclear membrane during mitosis, which is necessary for eukaryotic cell proliferation. However, the role of LMNB2 in colorectal cancer (CRC) is poorly understood. This study explored the biological functions of LMNB2 in the progression of colorectal cancer and explored the possible molecular mechanisms. We found that LMNB2 was significantly upregulated in primary colorectal cancer tissues and cell lines, compared with paired non-cancerous tissues and normal colorectal epithelium. The high expression of LMNB2 in colorectal cancer tissues is significantly related to the clinicopathological characteristics of the patients and the shorter overall and disease-free cumulative survival. Functional analysis, including CCK8 cell proliferation test, EdU proliferation test, colony formation analysis, nude mouse xenograft, cell cycle, and apoptosis analysis showed that LMNB2 significantly promotes cell proliferation by promoting cell cycle progression in vivo and in vitro. In addition, gene set enrichment analysis, luciferase report analysis, and CHIP analysis showed that LMNB2 promotes cell proliferation by regulating the p21 promoter, whereas LMNB2 has no effect on cell apoptosis. In summary, these findings not only indicate that LMNB2 promotes the proliferation of colorectal cancer by regulating p21-mediated cell cycle progression, but also suggest the potential value of LMNB2 as a clinical prognostic marker and molecular therapy target.

scholarly journals Hyperbaric oxygen promotes not only glioblastoma proliferation but also chemosensitization by inhibiting HIF1α/HIF2α-Sox2

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Pan Wang ◽  
Sheng Gong ◽  
Jinyu Pan ◽  
Junwei Wang ◽  
Dewei Zou ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Cell Cycle Arrest ◽  
Hyperbaric Oxygen ◽  
Cell Cycle Progression ◽  
Malignant Progression ◽  
Cycle Progression ◽  
Chemotherapy Sensitivity ◽  
Hypoxic Conditions ◽  
Cycle Arrest

AbstractThere exists a consensus that combining hyperbaric oxygen (HBO) and chemotherapy promotes chemotherapy sensitivity in GBM cells. However, few studies have explored the mechanism involved. HIF1α and HIF2α are the two main molecules that contribute to GBM malignant progression by inhibiting apoptosis or maintaining stemness under hypoxic conditions. Moreover, Sox2, a marker of stemness, also contributes to GBM malignant progression through stemness maintenance or cell cycle arrest. Briefly, HIF1α, HIF2α and Sox2 are highly expressed under hypoxia and contribute to GBM growth and chemoresistance. However, after exposure to HBO for GBM, whether the expression of the above factors is decreased, resulting in chemosensitization, remains unknown. Therefore, we performed a series of studies and determined that the expression of HIF1α, HIF2α and Sox2 was decreased after HBO and that HBO promoted GBM cell proliferation through cell cycle progression, albeit with a decrease in stemness, thus contributing to chemosensitization via the inhibition of HIF1α/HIF2α-Sox2.

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