WorldWideScience

Sample records for regulates cell-cycle genes

  1. The cell cycle-regulated genes of Schizosaccharomyces pombe.

    Science.gov (United States)

    Oliva, Anna; Rosebrock, Adam; Ferrezuelo, Francisco; Pyne, Saumyadipta; Chen, Haiying; Skiena, Steve; Futcher, Bruce; Leatherwood, Janet

    2005-07-01

    Many genes are regulated as an innate part of the eukaryotic cell cycle, and a complex transcriptional network helps enable the cyclic behavior of dividing cells. This transcriptional network has been studied in Saccharomyces cerevisiae (budding yeast) and elsewhere. To provide more perspective on these regulatory mechanisms, we have used microarrays to measure gene expression through the cell cycle of Schizosaccharomyces pombe (fission yeast). The 750 genes with the most significant oscillations were identified and analyzed. There were two broad waves of cell cycle transcription, one in early/mid G2 phase, and the other near the G2/M transition. The early/mid G2 wave included many genes involved in ribosome biogenesis, possibly explaining the cell cycle oscillation in protein synthesis in S. pombe. The G2/M wave included at least three distinctly regulated clusters of genes: one large cluster including mitosis, mitotic exit, and cell separation functions, one small cluster dedicated to DNA replication, and another small cluster dedicated to cytokinesis and division. S. pombe cell cycle genes have relatively long, complex promoters containing groups of multiple DNA sequence motifs, often of two, three, or more different kinds. Many of the genes, transcription factors, and regulatory mechanisms are conserved between S. pombe and S. cerevisiae. Finally, we found preliminary evidence for a nearly genome-wide oscillation in gene expression: 2,000 or more genes undergo slight oscillations in expression as a function of the cell cycle, although whether this is adaptive, or incidental to other events in the cell, such as chromatin condensation, we do not know.

  2. The cell cycle-regulated genes of Schizosaccharomyces pombe.

    Directory of Open Access Journals (Sweden)

    Anna Oliva

    2005-07-01

    Full Text Available Many genes are regulated as an innate part of the eukaryotic cell cycle, and a complex transcriptional network helps enable the cyclic behavior of dividing cells. This transcriptional network has been studied in Saccharomyces cerevisiae (budding yeast and elsewhere. To provide more perspective on these regulatory mechanisms, we have used microarrays to measure gene expression through the cell cycle of Schizosaccharomyces pombe (fission yeast. The 750 genes with the most significant oscillations were identified and analyzed. There were two broad waves of cell cycle transcription, one in early/mid G2 phase, and the other near the G2/M transition. The early/mid G2 wave included many genes involved in ribosome biogenesis, possibly explaining the cell cycle oscillation in protein synthesis in S. pombe. The G2/M wave included at least three distinctly regulated clusters of genes: one large cluster including mitosis, mitotic exit, and cell separation functions, one small cluster dedicated to DNA replication, and another small cluster dedicated to cytokinesis and division. S. pombe cell cycle genes have relatively long, complex promoters containing groups of multiple DNA sequence motifs, often of two, three, or more different kinds. Many of the genes, transcription factors, and regulatory mechanisms are conserved between S. pombe and S. cerevisiae. Finally, we found preliminary evidence for a nearly genome-wide oscillation in gene expression: 2,000 or more genes undergo slight oscillations in expression as a function of the cell cycle, although whether this is adaptive, or incidental to other events in the cell, such as chromatin condensation, we do not know.

  3. Identification of Cell Cycle-Regulated Genes by Convolutional Neural Network.

    Science.gov (United States)

    Liu, Chenglin; Cui, Peng; Huang, Tao

    2017-01-01

    The cell cycle-regulated genes express periodically with the cell cycle stages, and the identification and study of these genes can provide a deep understanding of the cell cycle process. Large false positives and low overlaps are big problems in cell cycle-regulated gene detection. Here, a computational framework called DLGene was proposed for cell cycle-regulated gene detection. It is based on the convolutional neural network, a deep learning algorithm representing raw form of data pattern without assumption of their distribution. First, the expression data was transformed to categorical state data to denote the changing state of gene expression, and four different expression patterns were revealed for the reported cell cycle-regulated genes. Then, DLGene was applied to discriminate the non-cell cycle gene and the four subtypes of cell cycle genes. Its performances were compared with six traditional machine learning methods. At last, the biological functions of representative cell cycle genes for each subtype are analyzed. Our method showed better and more balanced performance of sensitivity and specificity comparing to other machine learning algorithms. The cell cycle genes had very different expression pattern with non-cell cycle genes and among the cell-cycle genes, there were four subtypes. Our method not only detects the cell cycle genes, but also describes its expression pattern, such as when its highest expression level is reached and how it changes with time. For each type, we analyzed the biological functions of the representative genes and such results provided novel insight to the cell cycle mechanisms. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  4. Regulation of a transcription factor network by Cdk1 coordinates late cell cycle gene expression.

    Science.gov (United States)

    Landry, Benjamin D; Mapa, Claudine E; Arsenault, Heather E; Poti, Kristin E; Benanti, Jennifer A

    2014-05-02

    To maintain genome stability, regulators of chromosome segregation must be expressed in coordination with mitotic events. Expression of these late cell cycle genes is regulated by cyclin-dependent kinase (Cdk1), which phosphorylates a network of conserved transcription factors (TFs). However, the effects of Cdk1 phosphorylation on many key TFs are not known. We find that elimination of Cdk1-mediated phosphorylation of four S-phase TFs decreases expression of many late cell cycle genes, delays mitotic progression, and reduces fitness in budding yeast. Blocking phosphorylation impairs degradation of all four TFs. Consequently, phosphorylation-deficient mutants of the repressors Yox1 and Yhp1 exhibit increased promoter occupancy and decreased expression of their target genes. Interestingly, although phosphorylation of the transcriptional activator Hcm1 on its N-terminus promotes its degradation, phosphorylation on its C-terminus is required for its activity, indicating that Cdk1 both activates and inhibits a single TF. We conclude that Cdk1 promotes gene expression by both activating transcriptional activators and inactivating transcriptional repressors. Furthermore, our data suggest that coordinated regulation of the TF network by Cdk1 is necessary for faithful cell division.

  5. Cell cycle and anti-estrogen effects synergize to regulate cell proliferation and ER target gene expression.

    Directory of Open Access Journals (Sweden)

    Mathieu Dalvai

    Full Text Available Antiestrogens are designed to antagonize hormone induced proliferation and ERalpha target gene expression in mammary tumor cells. Commonly used drugs such as OH-Tamoxifen and ICI 182780 (Fulvestrant block cell cycle progression in G0/G1. Inversely, the effect of cell cycle stage on ER regulated gene expression has not been tested directly. We show that in ERalpha-positive breast cancer cells (MCF-7 the estrogen receptor gene and downstream target genes are cell cycle regulated with expression levels varying as much as three-fold between phases of the cell cycle. Steroid free culture conditions commonly used to assess the effect of hormones or antiestrogens on gene expression also block MCF-7 cells in G1-phase when several ERalpha target genes are overexpressed. Thus, cell cycle effects have to be taken into account when analyzing the impact of hormonal treatments on gene transcription. We found that antiestrogens repress transcription of several ERalpha target genes specifically in S phase. This observation corroborates the more rapid and strong impact of antiestrogen treatments on cell proliferation in thymidine, hydroxyurea or aphidicolin arrested cells and correlates with an increase of apoptosis compared to similar treatments in lovastatin or nocodazol treated cells. Hence, cell cycle effects synergize with the action of antiestrogens. An interesting therapeutic perspective could be to enhance the action of anti-estrogens by associating hormone-therapy with specific cell cycle drugs.

  6. Simulation of E. coli gene regulation including overlapping cell cycles, growth, division, time delays and noise.

    Directory of Open Access Journals (Sweden)

    Ruoyu Luo

    Full Text Available Due to the complexity of biological systems, simulation of biological networks is necessary but sometimes complicated. The classic stochastic simulation algorithm (SSA by Gillespie and its modified versions are widely used to simulate the stochastic dynamics of biochemical reaction systems. However, it has remained a challenge to implement accurate and efficient simulation algorithms for general reaction schemes in growing cells. Here, we present a modeling and simulation tool, called 'GeneCircuits', which is specifically developed to simulate gene-regulation in exponentially growing bacterial cells (such as E. coli with overlapping cell cycles. Our tool integrates three specific features of these cells that are not generally included in SSA tools: 1 the time delay between the regulation and synthesis of proteins that is due to transcription and translation processes; 2 cell cycle-dependent periodic changes of gene dosage; and 3 variations in the propensities of chemical reactions that have time-dependent reaction rates as a consequence of volume expansion and cell division. We give three biologically relevant examples to illustrate the use of our simulation tool in quantitative studies of systems biology and synthetic biology.

  7. Mig-6 regulates endometrial genes involved in cell cycle and progesterone signaling

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Jung-Yoon; Kim, Tae Hoon; Lee, Jae Hee [Department of Obstetrics, Gynecology & Reproductive Biology, Michigan State University, Grand Rapids, MI (United States); Dunwoodie, Sally L. [Developmental and Stem Cell Biology Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales 2010 (Australia); St. Vincent' s Clinical School and the School of Biotechnology and Biomolecular Sciences, University of New South Wales, Kensington, New South Wales 2033 (Australia); Ku, Bon Jeong, E-mail: bonjeong@cnu.ac.kr [Department of Internal Medicine, Chungnam National University School of Medicine, Daejeon (Korea, Republic of); Jeong, Jae-Wook, E-mail: JaeWook.Jeong@hc.msu.edu [Department of Obstetrics, Gynecology & Reproductive Biology, Michigan State University, Grand Rapids, MI (United States); Department of Women' s Health, Spectrum Health System, Grand Rapids, MI (United States)

    2015-07-10

    Mitogen inducible gene 6 (Mig-6) is an important mediator of progesterone (P4) signaling to inhibit estrogen (E2) signaling in the uterus. Ablation of Mig-6 in the murine uterus leads to the development of endometrial hyperplasia and E2-induced endometrial cancer. To identify the molecular pathways regulated by Mig-6, we performed microarray analysis on the uterus of ovariectomized Mig-6{sup f/f} and PGR{sup cre/+}Mig-6{sup f/f} (Mig-6{sup d/d}) mice treated with vehicle or P4 for 6 h. The results revealed that 772 transcripts were significantly regulated in the Mig-6{sup d/d} uterus treated with vehicle as compared with Mig-6{sup f/f} mice. The pathway analysis showed that Mig-6 suppressed the expression of gene-related cell cycle regulation in the absence of ovarian steroid hormone. The epithelium of Mig-6{sup d/d} mice showed a significant increase in the number of proliferative cells compared to Mig-6{sup f/f} mice. This microarray analysis also revealed that 324 genes are regulated by P4 as well as Mig-6. Cited2, the developmentally important transcription factor, was identified as being regulated by the P4-Mig-6 axis. To determine the role of Cited2 in the uterus, we used the mice with Cited2 that were conditionally ablated in progesterone receptor-positive cells (PGR{sup cre/+}Cited2{sup f/f}; Cited2{sup d/d}). Ablation of Cited2 in the uterus resulted in a significant reduction in the ability of the uterus to undergo a hormonally induced decidual reaction. Identification and analysis of these responsive genes will help define the role of P4 as well as Mig-6 in regulating uterine biology. - Highlights: • We identify Mig-6- and P4-regulated uterine genes by microarray analysis. • Mig-6 suppresses cell cycle progression and epithelial cell proliferation in uterus. • We identify the Mig-6 dependent induced genes by P4. • Cited2 plays an important role for decidualization as a P4 and Mig-6 target gene.

  8. Cell cycle-regulated oscillator coordinates core histone gene transcription through histone acetylation.

    Science.gov (United States)

    Kurat, Christoph F; Lambert, Jean-Philippe; Petschnigg, Julia; Friesen, Helena; Pawson, Tony; Rosebrock, Adam; Gingras, Anne-Claude; Fillingham, Jeffrey; Andrews, Brenda

    2014-09-30

    DNA replication occurs during the synthetic (S) phase of the eukaryotic cell cycle and features a dramatic induction of histone gene expression for concomitant chromatin assembly. Ectopic production of core histones outside of S phase is toxic, underscoring the critical importance of regulatory pathways that ensure proper expression of histone genes. Several regulators of histone gene expression in the budding yeast Saccharomyces cerevisiae are known, yet the key oscillator responsible for restricting gene expression to S phase has remained elusive. Here, we show that suppressor of Ty (Spt)10, a putative histone acetyltransferase, and its binding partner Spt21 are key determinants of S-phase-specific histone gene expression. We show that Spt21 abundance is restricted to S phase in part by anaphase promoting complex Cdc20-homologue 1 (APC(Cdh1)) and that it is recruited to histone gene promoters in S phase by Spt10. There, Spt21-Spt10 enables the recruitment of a cascade of regulators, including histone chaperones and the histone-acetyltransferase general control nonderepressible (Gcn) 5, which we hypothesize lead to histone acetylation and consequent transcription activation.

  9. Cell cycle-regulated oscillator coordinates core histone gene transcription through histone acetylation

    Science.gov (United States)

    Kurat, Christoph F.; Lambert, Jean-Philippe; Petschnigg, Julia; Friesen, Helena; Pawson, Tony; Rosebrock, Adam; Gingras, Anne-Claude; Fillingham, Jeffrey; Andrews, Brenda

    2014-01-01

    DNA replication occurs during the synthetic (S) phase of the eukaryotic cell cycle and features a dramatic induction of histone gene expression for concomitant chromatin assembly. Ectopic production of core histones outside of S phase is toxic, underscoring the critical importance of regulatory pathways that ensure proper expression of histone genes. Several regulators of histone gene expression in the budding yeast Saccharomyces cerevisiae are known, yet the key oscillator responsible for restricting gene expression to S phase has remained elusive. Here, we show that suppressor of Ty (Spt)10, a putative histone acetyltransferase, and its binding partner Spt21 are key determinants of S-phase–specific histone gene expression. We show that Spt21 abundance is restricted to S phase in part by anaphase promoting complex Cdc20-homologue 1 (APCCdh1) and that it is recruited to histone gene promoters in S phase by Spt10. There, Spt21-Spt10 enables the recruitment of a cascade of regulators, including histone chaperones and the histone-acetyltransferase general control nonderepressible (Gcn) 5, which we hypothesize lead to histone acetylation and consequent transcription activation. PMID:25228766

  10. Cell cycle regulation of the cyclin A gene promoter is mediated by a variant E2F site

    DEFF Research Database (Denmark)

    Schulze, A; Zerfass, K; Spitkovsky, D

    1995-01-01

    Cyclin A is involved in the control of S phase and mitosis in mammalian cells. Expression of the cyclin A gene in nontransformed cells is characterized by repression of its promoter during the G1 phase of the cell cycle and its induction at S-phase entry. We show that this mode of regulation...

  11. Cell cycle gene expression under clinorotation

    Science.gov (United States)

    Artemenko, Olga

    2016-07-01

    Cyclins and cyclin-dependent kinase (CDK) are main regulators of the cell cycle of eukaryotes. It's assumes a significant change of their level in cells under microgravity conditions and by other physical factors actions. The clinorotation use enables to determine the influence of gravity on simulated events in the cell during the cell cycle - exit from the state of quiet stage and promotion presynthetic phase (G1) and DNA synthesis phase (S) of the cell cycle. For the clinorotation effect study on cell proliferation activity is the necessary studies of molecular mechanisms of cell cycle regulation and development of plants under altered gravity condition. The activity of cyclin D, which is responsible for the events of the cell cycle in presynthetic phase can be controlled by the action of endogenous as well as exogenous factors, but clinorotation is one of the factors that influence on genes expression that regulate the cell cycle.These data can be used as a model for further research of cyclin - CDK complex for study of molecular mechanisms regulation of growth and proliferation. In this investigation we tried to summarize and analyze known literature and own data we obtained relatively the main regulators of the cell cycle in altered gravity condition.

  12. PARP-2 regulates cell cycle-related genes through histone deacetylation and methylation independently of poly(ADP-ribosyl)ation

    International Nuclear Information System (INIS)

    Liang, Ya-Chen; Hsu, Chiao-Yu; Yao, Ya-Li; Yang, Wen-Ming

    2013-01-01

    Highlights: ► PARP-2 acts as a transcription co-repressor independently of PARylation activity. ► PARP-2 recruits HDAC5, 7, and G9a and generates repressive chromatin. ► PARP-2 is recruited to the c-MYC promoter by DNA-binding factor YY1. ► PARP-2 represses cell cycle-related genes and alters cell cycle progression. -- Abstract: Poly(ADP-ribose) polymerase-2 (PARP-2) catalyzes poly(ADP-ribosyl)ation (PARylation) and regulates numerous nuclear processes, including transcription. Depletion of PARP-2 alters the activity of transcription factors and global gene expression. However, the molecular action of how PARP-2 controls the transcription of target promoters remains unclear. Here we report that PARP-2 possesses transcriptional repression activity independently of its enzymatic activity. PARP-2 interacts and recruits histone deacetylases HDAC5 and HDAC7, and histone methyltransferase G9a to the promoters of cell cycle-related genes, generating repressive chromatin signatures. Our findings propose a novel mechanism of PARP-2 in transcriptional regulation involving specific protein–protein interactions and highlight the importance of PARP-2 in the regulation of cell cycle progression

  13. Regulation of the cell cycle by irradiation

    International Nuclear Information System (INIS)

    Akashi, Makoto

    1995-01-01

    The molecular mechanism of cell proliferation is extremely complex; deregulation results in neoplastic transformation. In eukaryotes, proliferation of cells is finely regulated through the cell cycle. Studies have shown that the cell cycle is regulated by s series of enzymes known as cyclin-dependent kinases (CDKs). The activities of CDKs are controlled by their association with regulatory subunits, cyclins; the expression of cyclins and the activation of the different cyclin-CDK complexes are required for the cell to cycle. Thus, the cell cycle is regulated by activating and inhibiting phosphorylation of the CDK subunits and this program has internal check points at different stages of the cell cycle. When cells are exposed to external insults such as DNA damaging agents, negative regulation of the cell cycle occurs; arrest in either G1 or G2 stage is induced to prevent the cells from prematurely entering into the next stage before DNA is repaired. Recently, a potent inhibitor of CDKs, which inhibits the phosphorylation of retinoblastoma susceptibility (Rb) gene product by cyclin A-CDK2, cyclin E-CDK2, cyclin D1-CDK4, and cyclin D2-CDK4 complexes has been identified. This protein named WAF1, Sdi1, Cip1, or p21 (a protein of Mr 21,000) contains a p53-binding site in its promoter and studies have reported that the expression of WAF1 was directly regulated by p53; cells with loss of p53 activity due to mutational alteration were unable to induce WAF1. This chapter will be focused on the mechanisms of the cell cycle including inhibitors of CDKs, and the induction of WAF1 by irradiation through a pathway independent of p53 will be also described. (author)

  14. The Arabidopsis Transcription Factor AtTCP15 Regulates Endoreduplication by Modulating Expression of Key Cell-cycle Genes

    Institute of Scientific and Technical Information of China (English)

    Zi-Yu Li; Bin Li; Ai-Wu Dong

    2012-01-01

    Plant cells frequently undergo endoreduplication,a modified cell cycle in which genome is repeatedly replicated without cytokinesis.As the key step to achieve final size and function for cells,endoreduplication is prevalent during plant development.However,mechanisms to control the balance between endoreduplication and mitotic cell division are still poorly understood.Here,we show that the Arabidopsis TCP (CINCINNATA-like TEOSINTE BRANCHED1-CYCLOIDEA-PCF)-family transcription factor gene AtTCP15 is expressed in trichomes,as well as in rapidly dividing and vascular tissues.Expression of AtTCP15SRDX,AtTCP15 fused with a SRDX repressor domain,induces extra endoreduplication in trichomes and cotyledon cells in transgenic Arabidopsis.On the contrary,overexpression of AtTCP15 suppresses endoreduplication in trichomes and other examined cells.Misregulation of AtTCP15 affects the expression of several important genes involved in cell-cycle regulation.AtTCP15 protein binds directly to the promoter regions of CYCA2;3 and RETINOBLASTOMA-RELATED (RBR) genes,which play key roles in endoreduplication.Taken together,AtTCP15 plays an important role in regulating endoreduplication during Arabidopsis development.

  15. Benzyl isothiocyanate alters the gene expression with cell cycle regulation and cell death in human brain glioblastoma GBM 8401 cells.

    Science.gov (United States)

    Tang, Nou-Ying; Chueh, Fu-Shin; Yu, Chien-Chih; Liao, Ching-Lung; Lin, Jen-Jyh; Hsia, Te-Chun; Wu, King-Chuen; Liu, Hsin-Chung; Lu, Kung-Wen; Chung, Jing-Gung

    2016-04-01

    Glioblastoma multiforme (GBM) is a highly malignant devastating brain tumor in adults. Benzyl isothiocyanate (BITC) is one of the isothiocyanates that have been shown to induce human cancer cell apoptosis and cell cycle arrest. Herein, the effect of BITC on cell viability and apoptotic cell death and the genetic levels of human brain glioblastoma GBM 8401 cells in vitro were investigated. We found that BITC induced cell morphological changes, decreased cell viability and the induction of cell apoptosis in GBM 8401 cells was time-dependent. cDNA microarray was used to examine the effects of BITC on GBM 8401 cells and we found that numerous genes associated with cell death and cell cycle regulation in GBM 8401 cells were altered after BITC treatment. The results show that expression of 317 genes was upregulated, and two genes were associated with DNA damage, the DNA-damage-inducible transcript 3 (DDIT3) was increased 3.66-fold and the growth arrest and DNA-damage-inducible α (GADD45A) was increased 2.34-fold. We also found that expression of 182 genes was downregulated and two genes were associated with receptor for cell responses to stimuli, the EGF containing fibulin-like extracellular matrix protein 1 (EFEMP1) was inhibited 2.01-fold and the TNF receptor-associated protein 1 (TRAP1) was inhibited 2.08-fold. BITC inhibited seven mitochondria ribosomal genes, the mitochondrial ribosomal protein; tumor protein D52 (MRPS28) was inhibited 2.06-fold, the mitochondria ribosomal protein S2 (MRPS2) decreased 2.07-fold, the mitochondria ribosomal protein L23 (MRPL23) decreased 2.08-fold, the mitochondria ribosomal protein S2 (MRPS2) decreased 2.07-fold, the mitochondria ribosomal protein S12 (MRPS12) decreased 2.08-fold, the mitochondria ribosomal protein L12 (MRPL12) decreased 2.25-fold and the mitochondria ribosomal protein S34 (MRPS34) was decreased 2.30-fold in GBM 8401 cells. These changes of gene expression can provide the effects of BITC on the genetic level and are

  16. JMJD2A attenuation affects cell cycle and tumourigenic inflammatory gene regulation in lipopolysaccharide stimulated neuroectodermal stem cells

    Energy Technology Data Exchange (ETDEWEB)

    Das, Amitabh, E-mail: amitabhdas.kn@gmail.com [Department of Bionanotechnology, Hanyang University, Seoul 133-791 (Korea, Republic of); Chai, Jin Choul, E-mail: jincchai@gmail.com [Department of Molecular and Life Science, Hanyang University, 1271 Sa 3-dong, Ansan 426-791, Gyeonggi-do (Korea, Republic of); Jung, Kyoung Hwa, E-mail: khjung2@gmail.com [Department of Molecular and Life Science, Hanyang University, 1271 Sa 3-dong, Ansan 426-791, Gyeonggi-do (Korea, Republic of); Das, Nando Dulal, E-mail: nando.hu@gmail.com [Clinical Research Centre, Inha University School of Medicine, Incheon 400-711 (Korea, Republic of); Kang, Sung Chul, E-mail: gujiju11@gmail.com [Department of Molecular and Life Science, Hanyang University, 1271 Sa 3-dong, Ansan 426-791, Gyeonggi-do (Korea, Republic of); Lee, Young Seek, E-mail: yslee@hanyang.ac.kr [Department of Molecular and Life Science, Hanyang University, 1271 Sa 3-dong, Ansan 426-791, Gyeonggi-do (Korea, Republic of); Seo, Hyemyung, E-mail: hseo@hanyang.ac.kr [Department of Molecular and Life Science, Hanyang University, 1271 Sa 3-dong, Ansan 426-791, Gyeonggi-do (Korea, Republic of); Chai, Young Gyu, E-mail: ygchai@hanyang.ac.kr [Department of Bionanotechnology, Hanyang University, Seoul 133-791 (Korea, Republic of); Department of Molecular and Life Science, Hanyang University, 1271 Sa 3-dong, Ansan 426-791, Gyeonggi-do (Korea, Republic of)

    2014-11-01

    JMJD2A is a lysine trimethyl-specific histone demethylase that is highly expressed in a variety of tumours. The role of JMJD2A in tumour progression remains unclear. The objectives of this study were to identify JMJD2A-regulated genes and understand the function of JMJD2A in p53-null neuroectodermal stem cells (p53{sup −/−} NE-4Cs). We determined the effect of LPS as a model of inflammation in p53{sup −/−} NE-4Cs and investigated whether the epigenetic modifier JMJD2A alter the expression of tumourigenic inflammatory genes. Global gene expression was measured in JMJD2A knockdown (kd) p53{sup −/−} NE-4Cs and in LPS-stimulated JMJD2A-kd p53{sup −/−} NE-4C cells. JMJD2A attenuation significantly down-regulated genes were Cdca2, Ccnd2, Ccnd1, Crebbp, IL6rα, and Stat3 related with cell cycle, proliferation, and inflammatory-disease responses. Importantly, some tumour-suppressor genes including Dapk3, Timp2 and TFPI were significantly up-regulated but were not affected by silencing of the JMJD2B. Furthermore, we confirmed the attenuation of JMJD2A also down-regulated Cdca2, Ccnd2, Crebbp, and Rest in primary NSCs isolated from the forebrains of E15 embryos of C57/BL6J mice with effective p53 inhibitor pifithrin-α (PFT-α). Transcription factor (TF) motif analysis revealed known binding patterns for CDC5, MYC, and CREB, as well as three novel motifs in JMJD2A-regulated genes. IPA established molecular networks. The molecular network signatures and functional gene-expression profiling data from this study warrants further investigation as an effective therapeutic target, and studies to elucidate the molecular mechanism of JMJD2A-kd-dependent effects in neuroectodermal stem cells should be performed. - Highlights: • Significant up-regulation of epigenetic modifier JMJD2A mRNA upon LPS treatment. • Inhibition of JMJD2A attenuated key inflammatory and tumourigenic genes. • Establishing IPA based functional genomics in JMJD2A-attenuated p53{sup

  17. Dichlorodiphenyltrichloroethane technical mixture regulates cell cycle and apoptosis genes through the activation of CAR and ERα in mouse livers

    Energy Technology Data Exchange (ETDEWEB)

    Kazantseva, Yuliya A.; Yarushkin, Andrei A. [Institute of Molecular Biology and Biophysics SB RAMS, Novosibirsk, Timakova str., 2, 630117 (Russian Federation); Pustylnyak, Vladimir O., E-mail: pustylnyak@ngs.ru [Institute of Molecular Biology and Biophysics SB RAMS, Novosibirsk, Timakova str., 2, 630117 (Russian Federation); Novosibirsk State University, Novosibirsk, Pirogova str., 2, 630090 (Russian Federation)

    2013-09-01

    Dichlorodiphenyltrichloroethane (DDT) is a widely used organochlorine pesticide and a xenoestrogen that promotes rodent hepatomegaly and tumours. A recent study has shown significant correlation between DDT serum concentration and liver cancer incidence in humans, but the underlying mechanisms remain elusive. We hypothesised that a mixture of DDT isomers could exert effects on the liver through pathways instead of classical ERs. The acute effects of a DDT mixture containing the two major isomers p,p′-DDT (85%) and o,p′-DDT (15%) on CAR and ERα receptors and their cell cycle and apoptosis target genes were studied in mouse livers. ChIP results demonstrated increased CAR and ERα recruitment to their specific target gene binding sites in response to the DDT mixture. The results of real-time RT-PCR were consistent with the ChIP data and demonstrated that the DDT was able to activate both CAR and ERα in mouse livers, leading to target gene transcriptional increases including Cyp2b10, Gadd45β, cMyc, Mdm2, Ccnd1, cFos and E2f1. Western blot analysis demonstrated increases in cell cycle progression proteins cMyc, Cyclin D1, CDK4 and E2f1 and anti-apoptosis proteins Mdm2 and Gadd45β. In addition, DDT exposure led to Rb phosphorylation. Increases in cell cycle progression and anti-apoptosis proteins were accompanied by a decrease in p53 content and its transcriptional activity. However, the DDT was unable to stimulate the β-catenin signalling pathway, which can play an important role in hepatocyte proliferation. Thus, our results indicate that DDT treatment may result in cell cycle progression and apoptosis inhibition through CAR- and ERα-mediated gene activation in mouse livers. These findings suggest that the proliferative and anti-apoptotic conditions induced by CAR and ERα activation may be important contributors to the early stages of hepatocarcinogenesis as produced by DDT in rodent livers. - Highlights: • DDT activated both CAR and ERα and their cell

  18. Dichlorodiphenyltrichloroethane technical mixture regulates cell cycle and apoptosis genes through the activation of CAR and ERα in mouse livers

    International Nuclear Information System (INIS)

    Kazantseva, Yuliya A.; Yarushkin, Andrei A.; Pustylnyak, Vladimir O.

    2013-01-01

    Dichlorodiphenyltrichloroethane (DDT) is a widely used organochlorine pesticide and a xenoestrogen that promotes rodent hepatomegaly and tumours. A recent study has shown significant correlation between DDT serum concentration and liver cancer incidence in humans, but the underlying mechanisms remain elusive. We hypothesised that a mixture of DDT isomers could exert effects on the liver through pathways instead of classical ERs. The acute effects of a DDT mixture containing the two major isomers p,p′-DDT (85%) and o,p′-DDT (15%) on CAR and ERα receptors and their cell cycle and apoptosis target genes were studied in mouse livers. ChIP results demonstrated increased CAR and ERα recruitment to their specific target gene binding sites in response to the DDT mixture. The results of real-time RT-PCR were consistent with the ChIP data and demonstrated that the DDT was able to activate both CAR and ERα in mouse livers, leading to target gene transcriptional increases including Cyp2b10, Gadd45β, cMyc, Mdm2, Ccnd1, cFos and E2f1. Western blot analysis demonstrated increases in cell cycle progression proteins cMyc, Cyclin D1, CDK4 and E2f1 and anti-apoptosis proteins Mdm2 and Gadd45β. In addition, DDT exposure led to Rb phosphorylation. Increases in cell cycle progression and anti-apoptosis proteins were accompanied by a decrease in p53 content and its transcriptional activity. However, the DDT was unable to stimulate the β-catenin signalling pathway, which can play an important role in hepatocyte proliferation. Thus, our results indicate that DDT treatment may result in cell cycle progression and apoptosis inhibition through CAR- and ERα-mediated gene activation in mouse livers. These findings suggest that the proliferative and anti-apoptotic conditions induced by CAR and ERα activation may be important contributors to the early stages of hepatocarcinogenesis as produced by DDT in rodent livers. - Highlights: • DDT activated both CAR and ERα and their cell

  19. The SFP1 gene product of Saccharomyces cerevisiae regulates G2/M transitions during the mitotic cell cycle and DNA-damage response

    International Nuclear Information System (INIS)

    Xu, Z.; Norris, D.

    1998-01-01

    In eukaryotic cells, checkpoint pathways arrest cell-cycle progression if a particular event has failed to complete appropriately or if an important intracellular structure is defective or damaged. Saccharomyces cerevisiae strains that lack the SFP1 gene fail to arrest at the G2 DNA-damage checkpoint in response to genomic injury, but maintain their ability to arrest at the replication and spindle-assembly checkpoints. sfp1D mutants are characterized by a premature entrance into mitosis during a normal (undamaged) cell cycle, while strains that overexpress Sfp1p exhibit delays in G2. Sfp1p therefore acts as a repressor of the G2/M transition, both in the normal cell cycle and in the G2 checkpoint pathway. Sfp1 is a nuclear protein with two Cys2His2 zinc-finger domains commonly found in transcription factors. We propose that Sfp1p regulates the expression of gene products involved in the G2/M transition during the mitotic cell cycle and the DNA-damage response. In support of this model, overexpression of Sfp1p induces the expression of the PDS1 gene, which is known to encode a protein that regulates the G2 checkpoint. (author)

  20. Cell Cycle Regulation of Stem Cells by MicroRNAs.

    Science.gov (United States)

    Mens, Michelle M J; Ghanbari, Mohsen

    2018-06-01

    MicroRNAs (miRNAs) are a class of small non-coding RNA molecules involved in the regulation of gene expression. They are involved in the fine-tuning of fundamental biological processes such as proliferation, differentiation, survival and apoptosis in many cell types. Emerging evidence suggests that miRNAs regulate critical pathways involved in stem cell function. Several miRNAs have been suggested to target transcripts that directly or indirectly coordinate the cell cycle progression of stem cells. Moreover, previous studies have shown that altered expression levels of miRNAs can contribute to pathological conditions, such as cancer, due to the loss of cell cycle regulation. However, the precise mechanism underlying miRNA-mediated regulation of cell cycle in stem cells is still incompletely understood. In this review, we discuss current knowledge of miRNAs regulatory role in cell cycle progression of stem cells. We describe how specific miRNAs may control cell cycle associated molecules and checkpoints in embryonic, somatic and cancer stem cells. We further outline how these miRNAs could be regulated to influence cell cycle progression in stem cells as a potential clinical application.

  1. Genome-Wide Studies Reveal that H3K4me3 Modification in Bivalent Genes Is Dynamically Regulated during the Pluripotent Cell Cycle and Stabilized upon Differentiation.

    Science.gov (United States)

    Grandy, Rodrigo A; Whitfield, Troy W; Wu, Hai; Fitzgerald, Mark P; VanOudenhove, Jennifer J; Zaidi, Sayyed K; Montecino, Martin A; Lian, Jane B; van Wijnen, André J; Stein, Janet L; Stein, Gary S

    2016-02-15

    Stem cell phenotypes are reflected by posttranslational histone modifications, and this chromatin-related memory must be mitotically inherited to maintain cell identity through proliferative expansion. In human embryonic stem cells (hESCs), bivalent genes with both activating (H3K4me3) and repressive (H3K27me3) histone modifications are essential to sustain pluripotency. Yet, the molecular mechanisms by which this epigenetic landscape is transferred to progeny cells remain to be established. By mapping genomic enrichment of H3K4me3/H3K27me3 in pure populations of hESCs in G2, mitotic, and G1 phases of the cell cycle, we found striking variations in the levels of H3K4me3 through the G2-M-G1 transition. Analysis of a representative set of bivalent genes revealed that chromatin modifiers involved in H3K4 methylation/demethylation are recruited to bivalent gene promoters in a cell cycle-dependent fashion. Interestingly, bivalent genes enriched with H3K4me3 exclusively during mitosis undergo the strongest upregulation after induction of differentiation. Furthermore, the histone modification signature of genes that remain bivalent in differentiated cells resolves into a cell cycle-independent pattern after lineage commitment. These results establish a new dimension of chromatin regulation important in the maintenance of pluripotency. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  2. Cell cycle and apoptosis genes in atherosclerosis

    NARCIS (Netherlands)

    Boesten, Lianne Simone Mirjam

    2006-01-01

    The work described in this thesis was aimed at identifying the role of cell cycle and apoptosis genes in atherosclerosis. Atherosclerosis is the primary cause of cardiovascular disease, a disorder occurring in the large and medium-sized arteries of the body. Although in the beginning 90s promising

  3. A viral microRNA down-regulates multiple cell cycle genes through mRNA 5'UTRs.

    Directory of Open Access Journals (Sweden)

    Finn Grey

    2010-06-01

    Full Text Available Global gene expression data combined with bioinformatic analysis provides strong evidence that mammalian miRNAs mediate repression of gene expression primarily through binding sites within the 3' untranslated region (UTR. Using RNA induced silencing complex immunoprecipitation (RISC-IP techniques we have identified multiple cellular targets for a human cytomegalovirus (HCMV miRNA, miR-US25-1. Strikingly, this miRNA binds target sites primarily within 5'UTRs, mediating significant reduction in gene expression. Intriguingly, many of the genes targeted by miR-US25-1 are associated with cell cycle control, including cyclin E2, BRCC3, EID1, MAPRE2, and CD147, suggesting that miR-US25-1 is targeting genes within a related pathway. Deletion of miR-US25-1 from HCMV results in over expression of cyclin E2 in the context of viral infection. Our studies demonstrate that a viral miRNA mediates translational repression of multiple cellular genes by targeting mRNA 5'UTRs.

  4. Dynamic ubiquitin signaling in cell cycle regulation.

    Science.gov (United States)

    Gilberto, Samuel; Peter, Matthias

    2017-08-07

    The cell division cycle is driven by a collection of enzymes that coordinate DNA duplication and separation, ensuring that genomic information is faithfully and perpetually maintained. The activity of the effector proteins that perform and coordinate these biological processes oscillates by regulated expression and/or posttranslational modifications. Ubiquitylation is a cardinal cellular modification and is long known for driving cell cycle transitions. In this review, we emphasize emerging concepts of how ubiquitylation brings the necessary dynamicity and plasticity that underlie the processes of DNA replication and mitosis. New studies, often focusing on the regulation of chromosomal proteins like DNA polymerases or kinetochore kinases, are demonstrating that ubiquitylation is a versatile modification that can be used to fine-tune these cell cycle events, frequently through processes that do not involve proteasomal degradation. Understanding how the increasing variety of identified ubiquitin signals are transduced will allow us to develop a deeper mechanistic perception of how the multiple factors come together to faithfully propagate genomic information. Here, we discuss these and additional conceptual challenges that are currently under study toward understanding how ubiquitin governs cell cycle regulation. © 2017 Gilberto and Peter.

  5. Morphological adaptation of sheep's rumen epithelium to high-grain diet entails alteration in the expression of genes involved in cell cycle regulation, cell proliferation and apoptosis.

    Science.gov (United States)

    Xu, Lei; Wang, Yue; Liu, Junhua; Zhu, Weiyun; Mao, Shengyong

    2018-01-01

    The objectives of this study were to characterize changes in the relative mRNA expression of candidate genes and proteins involved in cell cycle regulation, cell proliferation and apoptosis in the ruminal epithelium (RE) of sheep during high-grain (HG) diet adaptation. Twenty sheep were assigned to four groups with five animals each. These animals were assigned to different periods of HG diet (containing 40% forage and 60% concentrate mix) feeding. The HG groups received an HG diet for 7 (G7, n  = 5), 14 (G14, n  = 5) and 28 d (G28, n  = 5), respectively. In contrast, the control group (CON, n  = 5) was fed the forage-based diet for 28 d. The results showed that HG feeding linearly decreased ( P  genes IGFBP-2 ( P  = 0.034) and IGFBP 5 ( P  gene Caspase 8 decreased (quadratic, P  = 0.012), while Bad mRNA expression tended to decrease (cubic, P  = 0.053) after HG feeding. These results demonstrated sequential changes in rumen papillae size, cell cycle regulation and the genes involved in proliferation and apoptosis as time elapsed in feeding a high-grain diet to sheep.

  6. SmgGDS is a transient nucleolar protein that protects cells from nucleolar stress and promotes the cell cycle by regulating DREAM complex gene expression.

    Science.gov (United States)

    Gonyo, P; Bergom, C; Brandt, A C; Tsaih, S-W; Sun, Y; Bigley, T M; Lorimer, E L; Terhune, S S; Rui, H; Flister, M J; Long, R M; Williams, C L

    2017-12-14

    The chaperone protein and guanine nucleotide exchange factor SmgGDS (RAP1GDS1) is a key promoter of cancer cell proliferation and tumorigenesis. SmgGDS undergoes nucleocytoplasmic shuttling, suggesting that it has both cytoplasmic and nuclear functions that promote cancer. Previous studies indicate that SmgGDS binds cytoplasmic small GTPases and promotes their trafficking to the plasma membrane. In contrast, little is known about the functions of SmgGDS in the nucleus, or how these nuclear functions might benefit cancer cells. Here we show unique nuclear localization and regulation of gene transcription pathways by SmgGDS. Strikingly, SmgGDS depletion significantly reduces expression of over 600 gene products that are targets of the DREAM complex, which is a transcription factor complex that regulates expression of proteins controlling the cell cycle. The cell cycle regulators E2F1, MYC, MYBL2 (B-Myb) and FOXM1 are among the DREAM targets that are diminished by SmgGDS depletion. E2F1 is well known to promote G1 cell cycle progression, and the loss of E2F1 in SmgGDS-depleted cells provides an explanation for previous reports that SmgGDS depletion characteristically causes a G1 cell cycle arrest. We show that SmgGDS localizes in nucleoli, and that RNAi-mediated depletion of SmgGDS in cancer cells disrupts nucleolar morphology, signifying nucleolar stress. We show that nucleolar SmgGDS interacts with the RNA polymerase I transcription factor upstream binding factor (UBF). The RNAi-mediated depletion of UBF diminishes nucleolar localization of SmgGDS and promotes proteasome-mediated degradation of SmgGDS, indicating that nucleolar sequestration of SmgGDS by UBF stabilizes SmgGDS protein. The ability of SmgGDS to interact with UBF and localize in the nucleolus is diminished by expressing DiRas1 or DiRas2, which are small GTPases that bind SmgGDS and act as tumor suppressors. Taken together, our results support a novel nuclear role for SmgGDS in protecting malignant

  7. SETD1A modulates cell cycle progression through a miRNA network that regulates p53 target genes

    OpenAIRE

    Tajima, Ken; Yae, Toshifumi; Javaid, Sarah; Tam, Oliver; Comaills, Valentine; Morris, Robert; Wittner, Ben S.; Liu, Mingzhu; Engstrom, Amanda; Takahashi, Fumiyuki; Black, Joshua C.; Ramaswamy, Sridhar; Shioda, Toshihiro; Hammell, Molly; Haber, Daniel A.

    2015-01-01

    Expression of the p53-inducible antiproliferative gene BTG2 is suppressed in many cancers in the absence of inactivating gene mutations, suggesting alternative mechanisms of silencing. Using a shRNA screen targeting 43 histone lysine methyltransferases (KMTs), we show that SETD1A suppresses BTG2 expression through its induction of several BTG2-targeting miRNAs. This indirect but highly specific mechanism, by which a chromatin regulator that mediates transcriptional activating marks can lead t...

  8. Novel genes and pathways modulated by syndecan-1: implications for the proliferation and cell-cycle regulation of malignant mesothelioma cells.

    Directory of Open Access Journals (Sweden)

    Tünde Szatmári

    Full Text Available Malignant pleural mesothelioma is a highly malignant tumor, originating from mesothelial cells of the serous cavities. In mesothelioma the expression of syndecan-1 correlates to epithelioid morphology and inhibition of growth and migration. Our previous data suggest a complex role of syndecan-1 in mesothelioma cell proliferation although the exact underlying molecular mechanisms are not completely elucidated. The aim of this study is therefore to disclose critical genes and pathways affected by syndecan-1 in mesothelioma; in order to better understand its importance for tumor cell growth and proliferation. We modulated the expression of syndecan-1 in a human mesothelioma cell line via both overexpression and silencing, and followed the transcriptomic responses with microarray analysis. To project the transcriptome analysis on the full-dimensional picture of cellular regulation, we applied pathway analysis using Ingenuity Pathway Analysis (IPA and a novel method of network enrichment analysis (NEA which elucidated signaling relations between differentially expressed genes and pathways acting via various molecular mechanisms. Syndecan-1 overexpression had profound effects on genes involved in regulation of cell growth, cell cycle progression, adhesion, migration and extracellular matrix organization. In particular, expression of several growth factors, interleukins, and enzymes of importance for heparan sulfate sulfation pattern, extracellular matrix proteins and proteoglycans were significantly altered. Syndecan-1 silencing had less powerful effect on the transcriptome compared to overexpression, which can be explained by the already low initial syndecan-1 level of these cells. Nevertheless, 14 genes showed response to both up- and downregulation of syndecan-1. The "cytokine - cytokine-receptor interaction", the TGF-β, EGF, VEGF and ERK/MAPK pathways were enriched in both experimental settings. Most strikingly, nearly all analyzed pathways

  9. Identification of transcription factors linked to cell cycle regulation in Arabidopsis

    OpenAIRE

    Dehghan Nayeri, Fatemeh

    2014-01-01

    Cell cycle is an essential process in growth and development of living organisms consists of the replication and mitotic phases separated by 2 gap phases; G1 and G2. It is tightly controlled at the molecular level and especially at the level of transcription. Precise regulation of the cell cycle is of central significance for plant growth and development and transcription factors are global regulators of gene expression playing essential roles in cell cycle regulation. This study has uncovere...

  10. In vivo targeting of ADAM9 gene expression using lentivirus-delivered shRNA suppresses prostate cancer growth by regulating REG4 dependent cell cycle progression.

    Directory of Open Access Journals (Sweden)

    Che-Ming Liu

    Full Text Available Cancer cells respond to stress by activating a variety of survival signaling pathways. A disintegrin and metalloproteinase (ADAM 9 is upregulated during cancer progression and hormone therapy, functioning in part through an increase in reactive oxygen species. Here, we present in vitro and in vivo evidence that therapeutic targeting of ADAM9 gene expression by lentivirus-delivered small hairpin RNA (shRNA significantly inhibited proliferation of human prostate cancer cell lines and blocked tumor growth in a murine model of prostate cancer bone metastasis. Cell cycle studies confirmed an increase in the G1-phase and decrease in the S-phase population of cancer cells under starvation stress conditions, which correlated with elevated intracellular superoxide levels. Microarray data showed significantly decreased levels of regenerating islet-derived family member 4 (REG4 expression in prostate cancer cells with knockdown of ADAM9 gene expression. This REG4 downregulation also resulted in induction of expression of p21(Cip1/WAF1, which negatively regulates cyclin D1 and blocks the G1/S transition. Our data reveal a novel molecular mechanism of ADAM9 in the regulation of prostate cancer cell proliferation, and suggests a combined modality of ADAM9 shRNA gene therapy and cytotoxic agents for hormone refractory and bone metastatic prostate cancer.

  11. Molecular biological mechanism II. Molecular mechanisms of cell cycle regulation

    International Nuclear Information System (INIS)

    Jung, T.

    2000-01-01

    The cell cycle in eukaryotes is regulated by central cell cycle controlling protein kinase complexes. These protein kinase complexes consist of a catalytic subunit from the cyclin-dependent protein kinase family (CDK), and a regulatory subunit from the cyclin family. Cyclins are characterised by their periodic cell cycle related synthesis and destruction. Each cell cycle phase is characterised by a specific set of CDKs and cyclins. The activity of CDK/cyclin complexes is mainly regulated on four levels. It is controlled by specific phosphorylation steps, the synthesis and destruction of cyclins, the binding of specific inhibitor proteins, and by active control of their intracellular localisation. At several critical points within the cell cycle, named checkpoints, the integrity of the cellular genome is monitored. If damage to the genome or an unfinished prior cell cycle phase is detected, the cell cycle progression is stopped. These cell cycle blocks are of great importance to secure survival of cells. Their primary importance is to prevent the manifestation and heritable passage of a mutated genome to daughter cells. Damage sensing, DNA repair, cell cycle control and apoptosis are closely linked cellular defence mechanisms to secure genome integrity. Disregulation in one of these defence mechanisms are potentially correlated with an increased cancer risk and therefore in at least some cases with an increased radiation sensitivity. (orig.) [de

  12. Riboflavin Depletion Promotes Tumorigenesis in HEK293T and NIH3T3 Cells by Sustaining Cell Proliferation and Regulating Cell Cycle-Related Gene Transcription.

    Science.gov (United States)

    Long, Lin; He, Jian-Zhong; Chen, Ye; Xu, Xiu-E; Liao, Lian-Di; Xie, Yang-Min; Li, En-Min; Xu, Li-Yan

    2018-05-07

    Riboflavin is an essential component of the human diet and its derivative cofactors play an established role in oxidative metabolism. Riboflavin deficiency has been linked with various human diseases. The objective of this study was to identify whether riboflavin depletion promotes tumorigenesis. HEK293T and NIH3T3 cells were cultured in riboflavin-deficient or riboflavin-sufficient medium and passaged every 48 h. Cells were collected every 5 generations and plate colony formation assays were performed to observe cell proliferation. Subcutaneous tumorigenicity assays in NU/NU mice were used to observe tumorigenicity of riboflavin-depleted HEK293T cells. Mechanistically, gene expression profiling and gene ontology analysis were used to identify abnormally expressed genes induced by riboflavin depletion. Western blot analyses, cell cycle analyses, and chromatin immunoprecipitation were used to validate the expression of cell cycle-related genes. Plate colony formation of NIH3T3 and HEK293T cell lines was enhanced >2-fold when cultured in riboflavin-deficient medium for 10-20 generations. Moreover, we observed enhanced subcutaneous tumorigenicity in NU/NU mice following injection of riboflavin-depleted compared with normal HEK293T cells (55.6% compared with 0.0% tumor formation, respectively). Gene expression profiling and gene ontology analysis revealed that riboflavin depletion induced the expression of cell cycle-related genes. Validation experiments also found that riboflavin depletion decreased p21 and p27 protein levels by ∼20%, and increased cell cycle-related and expression-elevated protein in tumor (CREPT) protein expression >2-fold, resulting in cyclin D1 and CDK4 levels being increased ∼1.5-fold, and cell cycle acceleration. We also observed that riboflavin depletion decreased intracellular riboflavin levels by 20% and upregulated expression of riboflavin transporter genes, particularly SLC52A3, and that the changes in CREPT and SLC52A3 correlated with

  13. MicroRNA-424/503 cluster members regulate bovine granulosa cell proliferation and cell cycle progression by targeting SMAD7 gene through activin signalling pathway.

    Science.gov (United States)

    Pande, Hari Om; Tesfaye, Dawit; Hoelker, Michael; Gebremedhn, Samuel; Held, Eva; Neuhoff, Christiane; Tholen, Ernst; Schellander, Karl; Wondim, Dessie Salilew

    2018-05-01

    The granulosa cells are indispensable for follicular development and its function is orchestrated by several genes, which in turn posttranscriptionally regulated by microRNAs (miRNA). In our previous study, the miRRNA-424/503 cluster was found to be highly abundant in bovine granulosa cells (bGCs) of preovulatory dominant follicle compared to subordinate counterpart at day 19 of the bovine estrous cycle. Other study also indicated the involvement of miR-424/503 cluster in tumour cell resistance to apoptosis suggesting this miRNA cluster may involve in cell survival. However, the role of miR-424/503 cluster in granulosa cell function remains elusive Therefore, this study aimed to investigate the role of miRNA-424/503 cluster in bGCs function using microRNA gain- and loss-of-function approaches. The role of miR-424/503 cluster members in granulosa cell function was investigated by overexpressing or inhibiting its activity in vitro cultured granulosa cells using miR-424/503 mimic or inhibitor, respectively. Luciferase reporter assay showed that SMAD7 and ACVR2A are the direct targets of the miRNA-424/503 cluster members. In line with this, overexpression of miRNA-424/503 cluster members using its mimic and inhibition of its activity by its inhibitor reduced and increased, respectively the expression of SMAD7 and ACVR2A. Furthermore, flow cytometric analysis indicated that overexpression of miRNA-424/503 cluster members enhanced bGCs proliferation by promoting G1- to S- phase cell cycle transition. Modulation of miRNA-424/503 cluster members tended to increase phosphorylation of SMAD2/3 in the Activin signalling pathway. Moreover, sequence specific knockdown of SMAD7, the target gene of miRNA-424/503 cluster members, using small interfering RNA also revealed similar phenotypic and molecular alterations observed when miRNA-424/503 cluster members were overexpressed. Similarly, to get more insight about the role of miRNA-424/503 cluster members in activin signalling

  14. Rethinking cell-cycle-dependent gene expression in Schizosaccharomyces pombe.

    Science.gov (United States)

    Cooper, Stephen

    2017-11-01

    Three studies of gene expression during the division cycle of Schizosaccharomyces pombe led to the proposal that a large number of genes are expressed at particular times during the S. pombe cell cycle. Yet only a small fraction of genes proposed to be expressed in a cell-cycle-dependent manner are reproducible in all three published studies. In addition to reproducibility problems, questions about expression amplitudes, cell-cycle timing of expression, synchronization artifacts, and the problem with methods for synchronizing cells must be considered. These problems and complications prompt the idea that caution should be used before accepting the conclusion that there are a large number of genes expressed in a cell-cycle-dependent manner in S. pombe.

  15. Genes adopt non-optimal codon usage to generate cell cycle-dependent oscillations in protein levels

    DEFF Research Database (Denmark)

    Frenkel-Morgenstern, Milana; Danon, Tamar; Christian, Thomas

    2012-01-01

    The cell cycle is a temporal program that regulates DNA synthesis and cell division. When we compared the codon usage of cell cycle-regulated genes with that of other genes, we discovered that there is a significant preference for non-optimal codons. Moreover, genes encoding proteins that cycle a...

  16. Repressive histone methylation regulates cardiac myocyte cell cycle exit.

    Science.gov (United States)

    El-Nachef, Danny; Oyama, Kyohei; Wu, Yun-Yu; Freeman, Miles; Zhang, Yiqiang; Robb MacLellan, W

    2018-05-22

    Mammalian cardiac myocytes (CMs) stop proliferating soon after birth and subsequent heart growth comes from hypertrophy, limiting the adult heart's regenerative potential after injury. The molecular events that mediate CM cell cycle exit are poorly understood. To determine the epigenetic mechanisms limiting CM cycling in adult CMs (ACMs) and whether trimethylation of lysine 9 of histone H3 (H3K9me3), a histone modification associated with repressed chromatin, is required for the silencing of cell cycle genes, we developed a transgenic mouse model where H3K9me3 is specifically removed in CMs by overexpression of histone demethylase, KDM4D. Although H3K9me3 is found across the genome, its loss in CMs preferentially disrupts cell cycle gene silencing. KDM4D binds directly to cell cycle genes and reduces H3K9me3 levels at these promotors. Loss of H3K9me3 preferentially leads to increased cell cycle gene expression resulting in enhanced CM cycling. Heart mass was increased in KDM4D overexpressing mice by postnatal day 14 (P14) and continued to increase until 9-weeks of age. ACM number, but not size, was significantly increased in KDM4D expressing hearts, suggesting CM hyperplasia accounts for the increased heart mass. Inducing KDM4D after normal development specifically in ACMs resulted in increased cell cycle gene expression and cycling. We demonstrated that H3K9me3 is required for CM cell cycle exit and terminal differentiation in ACMs. Depletion of H3K9me3 in adult hearts prevents and reverses permanent cell cycle exit and allows hyperplastic growth in adult hearts in vivo. Copyright © 2017. Published by Elsevier Ltd.

  17. Network-based differential gene expression analysis suggests cell cycle related genes regulated by E2F1 underlie the molecular difference between smoker and non-smoker lung adenocarcinoma

    Science.gov (United States)

    2013-01-01

    Background Differential gene expression (DGE) analysis is commonly used to reveal the deregulated molecular mechanisms of complex diseases. However, traditional DGE analysis (e.g., the t test or the rank sum test) tests each gene independently without considering interactions between them. Top-ranked differentially regulated genes prioritized by the analysis may not directly relate to the coherent molecular changes underlying complex diseases. Joint analyses of co-expression and DGE have been applied to reveal the deregulated molecular modules underlying complex diseases. Most of these methods consist of separate steps: first to identify gene-gene relationships under the studied phenotype then to integrate them with gene expression changes for prioritizing signature genes, or vice versa. It is warrant a method that can simultaneously consider gene-gene co-expression strength and corresponding expression level changes so that both types of information can be leveraged optimally. Results In this paper, we develop a gene module based method for differential gene expression analysis, named network-based differential gene expression (nDGE) analysis, a one-step integrative process for prioritizing deregulated genes and grouping them into gene modules. We demonstrate that nDGE outperforms existing methods in prioritizing deregulated genes and discovering deregulated gene modules using simulated data sets. When tested on a series of smoker and non-smoker lung adenocarcinoma data sets, we show that top differentially regulated genes identified by the rank sum test in different sets are not consistent while top ranked genes defined by nDGE in different data sets significantly overlap. nDGE results suggest that a differentially regulated gene module, which is enriched for cell cycle related genes and E2F1 targeted genes, plays a role in the molecular differences between smoker and non-smoker lung adenocarcinoma. Conclusions In this paper, we develop nDGE to prioritize

  18. Iodine-131 treatment of thyroid cancer cells leads to suppression of cell proliferation followed by induction of cell apoptosis and cell cycle arrest by regulation of B-cell translocation gene 2-mediated JNK/NF-κB pathways

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, L.M.; Pang, A.X., E-mail: zhaoliming515@126.com [Department of Nuclear Medicine, Linyi People' s Hospital, Linyi (China); Department of Urology, Linyi People' s Hospital, Linyi (China)

    2017-10-01

    Iodine-131 ({sup 131}I) is widely used for the treatment of thyroid-related diseases. This study aimed to investigate the expression of p53 and BTG2 genes following {sup 131}I therapy in thyroid cancer cell line SW579 and the possible underlying mechanism. SW579 human thyroid squamous carcinoma cells were cultured and treated with {sup 131}I. They were then assessed for {sup 131}I uptake, cell viability, apoptosis, cell cycle arrest, p53 expression, and BTG2 gene expression. SW579 cells were transfected with BTG2 siRNA, p53 siRNA and siNC and were then examined for the same aforementioned parameters. When treated with a JNK inhibitor of SP600125 and {sup 131}I or with a NF-kB inhibitor of BMS-345541 and {sup 131}I, non-transfected SW579 cells were assessed in JNK/NFkB pathways. It was observed that {sup 131}I significantly inhibited cell proliferation, promoted cell apoptosis and cell cycle arrest. Both BTG2 and p53 expression were enhanced in a dose-dependent manner. An increase in cell viability by up-regulation in Bcl2 gene, a decrease in apoptosis by enhanced CDK2 gene expression and a decrease in cell cycle arrest at G{sub 0}/G{sub 1} phase were also observed in SW579 cell lines transfected with silenced BTG2 gene. When treated with SP600125 and {sup 131}I, the non transfected SW579 cell lines significantly inhibited JNK pathway, NF-kB pathway and the expression of BTG2. However, when treated with BMS-345541 and {sup 131}I, only the NF-kB pathway was suppressed. {sup 131}I suppressed cell proliferation, induced cell apoptosis, and promoted cell cycle arrest of thyroid cancer cells by up-regulating B-cell translocation gene 2-mediated activation of JNK/NF--κB pathways. (author)

  19. Cell cycle regulation of hematopoietic stem or progenitor cells.

    Science.gov (United States)

    Hao, Sha; Chen, Chen; Cheng, Tao

    2016-05-01

    The highly regulated process of blood production is achieved through the hierarchical organization of hematopoietic stem cell (HSC) subsets and their progenies, which differ in self-renewal and differentiation potential. Genetic studies in mice have demonstrated that cell cycle is tightly controlled by the complex interplay between extrinsic cues and intrinsic regulatory pathways involved in HSC self-renewal and differentiation. Deregulation of these cellular programs may transform HSCs or hematopoietic progenitor cells (HPCs) into disease-initiating stem cells, and can result in hematopoietic malignancies such as leukemia. While previous studies have shown roles for some cell cycle regulators and related signaling pathways in HSCs and HPCs, a more complete picture regarding the molecular mechanisms underlying cell cycle regulation in HSCs or HPCs is lacking. Based on accumulated studies in this field, the present review introduces the basic components of the cell cycle machinery and discusses their major cellular networks that regulate the dormancy and cell cycle progression of HSCs. Knowledge on this topic would help researchers and clinicians to better understand the pathogenesis of relevant blood disorders and to develop new strategies for therapeutic manipulation of HSCs.

  20. Protein kinase C signaling and cell cycle regulation

    Directory of Open Access Journals (Sweden)

    Adrian R Black

    2013-01-01

    Full Text Available A link between T cell proliferation and the protein kinase C (PKC family of serine/threonine kinases has been recognized for about thirty years. However, despite the wealth of information on PKC-mediated control of T cell activation, understanding of the effects of PKCs on the cell cycle machinery in this cell type remains limited. Studies in other systems have revealed important cell cycle-specific effects of PKC signaling that can either positively or negatively impact proliferation. The outcome of PKC activation is highly context-dependent, with the precise cell cycle target(s and overall effects determined by the specific isozyme involved, the timing of PKC activation, the cell type, and the signaling environment. Although PKCs can regulate all stages of the cell cycle, they appear to predominantly affect G0/G1 and G2. PKCs can modulate multiple cell cycle regulatory molecules, including cyclins, cyclin-dependent kinases (cdks, cdk inhibitors and cdc25 phosphatases; however, evidence points to Cip/Kip cdk inhibitors and D-type cyclins as key mediators of PKC-regulated cell cycle-specific effects. Several PKC isozymes can target Cip/Kip proteins to control G0/G1→S and/or G2→M transit, while effects on D-type cyclins regulate entry into and progression through G1. Analysis of PKC signaling in T cells has largely focused on its roles in T cell activation; thus, observed cell cycle effects are mainly positive. A prominent role is emerging for PKCθ, with non-redundant functions of other isozymes also described. Additional evidence points to PKCδ as a negative regulator of the cell cycle in these cells. As in other cell types, context-dependent effects of individual isozymes have been noted in T cells, and Cip/Kip cdk inhibitors and D-type cyclins appear to be major PKC targets. Future studies are anticipated to take advantage of the similarities between these various systems to enhance understanding of PKC-mediated cell cycle regulation in

  1. Estrogen receptor alpha is cell cycle-regulated and regulates the cell cycle in a ligand-dependent fashion.

    Science.gov (United States)

    JavanMoghadam, Sonia; Weihua, Zhang; Hunt, Kelly K; Keyomarsi, Khandan

    2016-06-17

    Estrogen receptor alpha (ERα) has been implicated in several cell cycle regulatory events and is an important predictive marker of disease outcome in breast cancer patients. Here, we aimed to elucidate the mechanism through which ERα influences proliferation in breast cancer cells. Our results show that ERα protein is cell cycle-regulated in human breast cancer cells and that the presence of 17-β-estradiol (E2) in the culture medium shortened the cell cycle significantly (by 4.5 hours, P cycle duration were observed in the S and G2/M phases, whereas the G1 phase was indistinguishable under liganded and unliganded conditions. In addition, ERα knockdown in MCF-7 cells accelerated mitotic exit, whereas transfection of ERα-negative MDA-MB-231 cells with exogenous ERα significantly shortened the S and G2/M phases (by 9.1 hours, P cycle progression through the S and G2/M phases than fulvestrant does, presumably because of the destabilizing effect of fulvestrant on ERα protein. Together, these results show that ERα modulates breast cancer cell proliferation by regulating events during the S and G2/M phases of the cell cycle in a ligand-dependent fashion. These results provide the rationale for an effective treatment strategy that includes a cell cycle inhibitor in combination with a drug that lowers estrogen levels, such as an aromatase inhibitor, and an antiestrogen that does not result in the degradation of ERα, such as tamoxifen.

  2. Cloning and characterization of a cell cycle-regulated gene encoding topoisomerase I from Nicotiana tabacum that is inducible by light, low temperature and abscisic acid.

    Science.gov (United States)

    Mudgil, Y; Singh, B N; Upadhyaya, K C; Sopory, S K; Reddy, M K

    2002-05-01

    We have cloned a full-length 2874-bp cDNA coding for tobacco topoisomerase I, with an ORF of 2559 bp encoding a protein of 852 amino acids with a calculated molecular mass of 95 kDa and an estimated pI of 9.51. The deduced amino acid sequence shows homology to other eukaryotic topoisomerases I. Tobacco topoisomerase I was over-expressed in Escherichia coli, and the purified recombinant protein was found to relax both positively and negatively super-coiled DNA in the absence of the divalent cation Mg(2+)and ATP. These characteristic features indicate that the tobacco enzyme is a type I topoisomerase. The recombinant protein could be phosphorylated at (a) threonine residue(s) by protein kinase C. However, phosphorylation did not cause any change in its enzymatic activity. The genomic organization of the topoisomerase I gene revealed the presence of 8 exons and 7 introns in the region corresponding to the ORF and one intron in the 3' UTR region. Transcript analysis using RT-PCR showed basal constitutive expression in all organs examined, and the gene was expressed at all stages of the cell cycle--but the level of expression increased during the G1-S phase. The transcript level also increased following exposure to light, low-temperature stress and abscisic acid, a stress hormone.

  3. Senescence-associated microRNAs target cell cycle regulatory genes in normal human lung fibroblasts.

    Science.gov (United States)

    Markopoulos, Georgios S; Roupakia, Eugenia; Tokamani, Maria; Vartholomatos, George; Tzavaras, Theodore; Hatziapostolou, Maria; Fackelmayer, Frank O; Sandaltzopoulos, Raphael; Polytarchou, Christos; Kolettas, Evangelos

    2017-10-01

    Senescence recapitulates the ageing process at the cell level. A senescent cell stops dividing and exits the cell cycle. MicroRNAs (miRNAs) acting as master regulators of transcription, have been implicated in senescence. In the current study we investigated and compared the expression of miRNAs in young versus senescent human fibroblasts (HDFs), and analysed the role of mRNAs expressed in replicative senescent HFL-1 HDFs. Cell cycle analysis confirmed that HDFs accumulated in G 1 /S cell cycle phase. Nanostring analysis of isolated miRNAs from young and senescent HFL-1 showed that a distinct set of 15 miRNAs were significantly up-regulated in senescent cells including hsa-let-7d-5p, hsa-let-7e-5p, hsa-miR-23a-3p, hsa-miR-34a-5p, hsa-miR-122-5p, hsa-miR-125a-3p, hsa-miR-125a-5p, hsa-miR-125b-5p, hsa-miR-181a-5p, hsa-miR-221-3p, hsa-miR-222-3p, hsa-miR-503-5p, hsa-miR-574-3p, hsa-miR-574-5p and hsa-miR-4454. Importantly, pathway analysis of miRNA target genes down-regulated during replicative senescence in a public RNA-seq data set revealed a significant high number of genes regulating cell cycle progression, both G 1 /S and G 2 /M cell cycle phase transitions and telomere maintenance. The reduced expression of selected miRNA targets, upon replicative and oxidative-stress induced senescence, such as the cell cycle effectors E2F1, CcnE, Cdc6, CcnB1 and Cdc25C was verified at the protein and/or RNA levels. Induction of G1/S cell cycle phase arrest and down-regulation of cell cycle effectors correlated with the up-regulation of miR-221 upon both replicative and oxidative stress-induced senescence. Transient expression of miR-221/222 in HDFs promoted the accumulation of HDFs in G1/S cell cycle phase. We propose that miRNAs up-regulated during replicative senescence may act in concert to induce cell cycle phase arrest and telomere erosion, establishing a senescent phenotype. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Bombyx mori cyclin-dependent kinase inhibitor is involved in regulation of the silkworm cell cycle.

    Science.gov (United States)

    Tang, X-F; Zhou, X-L; Zhang, Q; Chen, P; Lu, C; Pan, M-H

    2018-06-01

    Cyclin-dependent kinase inhibitors (CKIs) are negative regulators of the cell cycle. They can bind to cyclin-dependent kinase (CDK)-cyclin complexes and inhibit CDK activities. We identified a single homologous gene of the CDK interacting protein/kinase inhibitory protein (Cip/Kip) family, BmCKI, in the silkworm, Bombyx mori. The gene transcribes two splice variants: a 654-bp-long BmCKI-L (the longer splice variant) encoding a protein with 217 amino acids and a 579-bp-long BmCKI-S (the shorter splice variant) encoding a protein with 192 amino acids. BmCKI-L and BmCKI-S contain the Cip/Kip family conserved cyclin-binding domain and the CDK-binding domain. They are localized in the nucleus and have an unconventional bipartite nuclear localization signal at amino acid residues 181-210. Overexpression of BmCKI-L or BmCKI-S affected cell cycle progression; the cell cycle was arrested in the first gap phase of cell cycle (G1). RNA interference of BmCKI-L or BmCKI-S led to cells accumulating in the second gap phase and the mitotic phase of cell cycle (G2/M). Both BmCKI-L and BmCKI-S are involved in cell cycle regulation and probably have similar effects. The transgenic silkworm with BmCKI-L overexpression (BmCKI-L-OE), exhibited embryonic lethal, larva developmental retardation and lethal phenotypes. These results suggest that BmCKI-L might regulate the growth and development of silkworm. These findings clarify the function of CKIs and increase our understanding of cell cycle regulation in the silkworm. © 2018 The Royal Entomological Society.

  5. Effects of γ-radiation on cell growth, cell cycle and promoter methylation of 22 cell cycle genes in the 1321NI astrocytoma cell line.

    Science.gov (United States)

    Alghamian, Yaman; Abou Alchamat, Ghalia; Murad, Hossam; Madania, Ammar

    2017-09-01

    DNA damage caused by radiation initiates biological responses affecting cell fate. DNA methylation regulates gene expression and modulates DNA damage pathways. Alterations in the methylation profiles of cell cycle regulating genes may control cell response to radiation. In this study we investigated the effect of ionizing radiation on the methylation levels of 22 cell cycle regulating genes in correlation with gene expression in 1321NI astrocytoma cell line. 1321NI cells were irradiated with 2, 5 or 10Gy doses then analyzed after 24, 48 and 72h for cell viability using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliu bromide) assay. Flow cytometry were used to study the effect of 10Gy irradiation on cell cycle. EpiTect Methyl II PCR Array was used to identify differentially methylated genes in irradiated cells. Changes in gene expression was determined by qPCR. Azacytidine treatment was used to determine whether DNA methylation affectes gene expression. Our results showed that irradiation decreased cell viability and caused cell cycle arrest at G2/M. Out of 22 genes tested, only CCNF and RAD9A showed some increase in DNA methylation (3.59% and 3.62%, respectively) after 10Gy irradiation, and this increase coincided with downregulation of both genes (by 4 and 2 fold, respectively). with azacytidine confirmed that expression of CCNF and RAD9A genes was regulated by methylation. 1321NI cell line is highly radioresistant and that irradiation of these cells with a 10Gy dose increases DNA methylation of CCNF and RAD9A genes. This dose down-regulates these genes, favoring G2/M arrest. Copyright © 2017 Medical University of Bialystok. Published by Elsevier B.V. All rights reserved.

  6. Cyclebase 3.0: a multi-organism database on cell-cycle regulation and phenotypes.

    Science.gov (United States)

    Santos, Alberto; Wernersson, Rasmus; Jensen, Lars Juhl

    2015-01-01

    The eukaryotic cell division cycle is a highly regulated process that consists of a complex series of events and involves thousands of proteins. Researchers have studied the regulation of the cell cycle in several organisms, employing a wide range of high-throughput technologies, such as microarray-based mRNA expression profiling and quantitative proteomics. Due to its complexity, the cell cycle can also fail or otherwise change in many different ways if important genes are knocked out, which has been studied in several microscopy-based knockdown screens. The data from these many large-scale efforts are not easily accessed, analyzed and combined due to their inherent heterogeneity. To address this, we have created Cyclebase--available at http://www.cyclebase.org--an online database that allows users to easily visualize and download results from genome-wide cell-cycle-related experiments. In Cyclebase version 3.0, we have updated the content of the database to reflect changes to genome annotation, added new mRNA and protein expression data, and integrated cell-cycle phenotype information from high-content screens and model-organism databases. The new version of Cyclebase also features a new web interface, designed around an overview figure that summarizes all the cell-cycle-related data for a gene. © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.

  7. Methylselenol, a selenium metabolite, induces cell cycle arrest in G1 phase and apoptosis via the extracellular-regulated kinase 1/2 pathway and other cancer signaling genes.

    Science.gov (United States)

    Zeng, Huawei; Wu, Min; Botnen, James H

    2009-09-01

    Methylselenol has been hypothesized to be a critical selenium (Se) metabolite for anticancer activity in vivo, and our previous study demonstrated that submicromolar methylselenol generated by incubating methionase with seleno-l-methionine inhibits the migration and invasive potential of HT1080 tumor cells. However, little is known about the association between cancer signal pathways and methylselenol's inhibition of tumor cell invasion. In this study, we demonstrated that methylselenol exposure inhibited cell growth and we used a cancer signal pathway-specific array containing 15 different signal transduction pathways involved in oncogenesis to study the effect of methylselenol on cellular signaling. Using real-time RT-PCR, we confirmed that cellular mRNA levels of cyclin-dependent kinase inhibitor 1C (CDKN1C), heme oxygenase 1, platelet/endothelial cell adhesion molecule, and PPARgamma genes were upregulated to 2.8- to 5.7-fold of the control. BCL2-related protein A1, hedgehog interacting protein, and p53 target zinc finger protein genes were downregulated to 26-52% of the control, because of methylselenol exposure. These genes are directly related to the regulation of cell cycle and apoptosis. Methylselenol increased apoptotic cells up to 3.4-fold of the control and inhibited the extracellular-regulated kinase 1/2 (ERK1/2) signaling and cellular myelocytomatosis oncogene (c-Myc) expression. Taken together, our studies identify 7 novel methylselenol responsive genes and demonstrate that methylselenol inhibits ERK1/2 pathway activation and c-Myc expression. The regulation of these genes is likely to play a key role in G1 cell cycle arrest and apoptosis, which may contribute to the inhibition of tumor cell invasion.

  8. The functional role for condensin in the regulation of chromosomal organization during the cell cycle.

    Science.gov (United States)

    Kagami, Yuya; Yoshida, Kiyotsugu

    2016-12-01

    In all organisms, the control of cell cycle progression is a fundamental process that is essential for cell growth, development, and survival. Through each cell cycle phase, the regulation of chromatin organization is essential for natural cell proliferation and maintaining cellular homeostasis. During mitosis, the chromatin morphology is dramatically changed to have a "thread-like" shape and the condensed chromosomes are segregated equally into two daughter cells. Disruption of the mitotic chromosome architecture physically impedes chromosomal behaviors, such as chromosome alignment and chromosome segregation; therefore, the proper mitotic chromosome structure is required to maintain chromosomal stability. Accumulating evidence has demonstrated that mitotic chromosome condensation is induced by condensin complexes. Moreover, recent studies have shown that condensin also modulates interphase chromatin and regulates gene expression. This review mainly focuses on the molecular mechanisms that condensin uses to exert its functions during the cell cycle progression. Moreover, we discuss the condensin-mediated chromosomal organization in cancer cells.

  9. NSA2, a novel nucleolus protein regulates cell proliferation and cell cycle

    International Nuclear Information System (INIS)

    Zhang, Heyu; Ma, Xi; Shi, Taiping; Song, Quansheng; Zhao, Hongshan; Ma, Dalong

    2010-01-01

    NSA2 (Nop seven-associated 2) was previously identified in a high throughput screen of novel human genes associated with cell proliferation, and the NSA2 protein is evolutionarily conserved across different species. In this study, we revealed that NSA2 is broadly expressed in human tissues and cultured cell lines, and located in the nucleolus of the cell. Both of the putative nuclear localization signals (NLSs) of NSA2, also overlapped with nucleolar localization signals (NoLSs), are capable of directing nucleolar accumulation. Moreover, over-expression of the NSA2 protein promoted cell growth in different cell lines and regulated the G1/S transition in the cell cycle. SiRNA silencing of the NSA2 transcript attenuated the cell growth and dramatically blocked the cell cycle in G1/S transition. Our results demonstrated that NSA2 is a nucleolar protein involved in cell proliferation and cell cycle regulation.

  10. Discovery of a Splicing Regulator Required for Cell Cycle Progression

    Energy Technology Data Exchange (ETDEWEB)

    Suvorova, Elena S.; Croken, Matthew; Kratzer, Stella; Ting, Li-Min; Conde de Felipe, Magnolia; Balu, Bharath; Markillie, Lye Meng; Weiss, Louis M.; Kim, Kami; White, Michael W.

    2013-02-01

    In the G1 phase of the cell division cycle, eukaryotic cells prepare many of the resources necessary for a new round of growth including renewal of the transcriptional and protein synthetic capacities and building the machinery for chromosome replication. The function of G1 has an early evolutionary origin and is preserved in single and multicellular organisms, although the regulatory mechanisms conducting G1 specific functions are only understood in a few model eukaryotes. Here we describe a new G1 mutant from an ancient family of apicomplexan protozoans. Toxoplasma gondii temperature-sensitive mutant 12-109C6 conditionally arrests in the G1 phase due to a single point mutation in a novel protein containing a single RNA-recognition-motif (TgRRM1). The resulting tyrosine to asparagine amino acid change in TgRRM1 causes severe temperature instability that generates an effective null phenotype for this protein when the mutant is shifted to the restrictive temperature. Orthologs of TgRRM1 are widely conserved in diverse eukaryote lineages, and the human counterpart (RBM42) can functionally replace the missing Toxoplasma factor. Transcriptome studies demonstrate that gene expression is downregulated in the mutant at the restrictive temperature due to a severe defect in splicing that affects both cell cycle and constitutively expressed mRNAs. The interaction of TgRRM1 with factors of the tri-SNP complex (U4/U6 & U5 snRNPs) indicate this factor may be required to assemble an active spliceosome. Thus, the TgRRM1 family of proteins is an unrecognized and evolutionarily conserved class of splicing regulators. This study demonstrates investigations into diverse unicellular eukaryotes, like the Apicomplexa, have the potential to yield new insights into important mechanisms conserved across modern eukaryotic kingdoms.

  11. The Mammalian Cell Cycle Regulates Parvovirus Nuclear Capsid Assembly

    Science.gov (United States)

    Riolobos, Laura; Domínguez, Carlos; Kann, Michael; Almendral, José M.

    2015-01-01

    It is unknown whether the mammalian cell cycle could impact the assembly of viruses maturing in the nucleus. We addressed this question using MVM, a reference member of the icosahedral ssDNA nuclear parvoviruses, which requires cell proliferation to infect by mechanisms partly understood. Constitutively expressed MVM capsid subunits (VPs) accumulated in the cytoplasm of mouse and human fibroblasts synchronized at G0, G1, and G1/S transition. Upon arrest release, VPs translocated to the nucleus as cells entered S phase, at efficiencies relying on cell origin and arrest method, and immediately assembled into capsids. In synchronously infected cells, the consecutive virus life cycle steps (gene expression, proteins nuclear translocation, capsid assembly, genome replication and encapsidation) proceeded tightly coupled to cell cycle progression from G0/G1 through S into G2 phase. However, a DNA synthesis stress caused by thymidine irreversibly disrupted virus life cycle, as VPs became increasingly retained in the cytoplasm hours post-stress, forming empty capsids in mouse fibroblasts, thereby impairing encapsidation of the nuclear viral DNA replicative intermediates. Synchronously infected cells subjected to density-arrest signals while traversing early S phase also blocked VPs transport, resulting in a similar misplaced cytoplasmic capsid assembly in mouse fibroblasts. In contrast, thymidine and density arrest signals deregulating virus assembly neither perturbed nuclear translocation of the NS1 protein nor viral genome replication occurring under S/G2 cycle arrest. An underlying mechanism of cell cycle control was identified in the nuclear translocation of phosphorylated VPs trimeric assembly intermediates, which accessed a non-conserved route distinct from the importin α2/β1 and transportin pathways. The exquisite cell cycle-dependence of parvovirus nuclear capsid assembly conforms a novel paradigm of time and functional coupling between cellular and virus life

  12. Cell Cycle Regulation by Alternative Polyadenylation of CCND1.

    Science.gov (United States)

    Wang, Qiong; He, Guopei; Hou, Mengmeng; Chen, Liutao; Chen, Shangwu; Xu, Anlong; Fu, Yonggui

    2018-05-01

    Global shortening of 3'UTRs by alternative polyadenylation (APA) has been observed in cancer cells. However, the role of APA in cancer remains unknown. CCND1 is a proto-oncogene that regulates progression through the G1-S phase of the cell cycle; moreover, it has been observed to be switching to proximal APA sites in cancer cells. To investigate the biological function of the APA of CCND1, we edited the weak poly(A) signal (PAS) of the proximal APA site to a canonical PAS using the CRISPR/Cas9 method, which can force the cells to use a proximal APA site. Cell cycle profiling and proliferation assays revealed that the proximal APA sites of CCND1 accelerated the cell cycle and promoted cell proliferation, but UTR-APA and CR-APA act via different molecular mechanisms. These results indicate that PAS editing with CRISPR/Cas9 provides a good method by which to study the biological function of APA.

  13. Studies on regulation of the cell cycle in fission yeast.

    Directory of Open Access Journals (Sweden)

    Miroslava Požgajová

    2015-05-01

    Full Text Available All living organisms including plants and animals are composed of millions of cells. These cells perform different functions for the organism although they possess the same chromosomes and carry the same genetic information. Thus, to be able to understand multicellular organism we need to understand the life cycle of individual cells from which the organism comprises. The cell cycle is the life cycle of a single cell in the plant or animal body. It involves series of events in which components of the cell doubles and afterwards equally segregate into daughter cells. Such process ensures growth of the organism, and specialized reductional cell division which leads to production of gamets, assures sexual reproduction. Cell cycle is divided in the G1, S, G2 and M phase. Two gap-phases (G1 and G2 separate S phase (or synthesis and M phase which stays either for mitosis or meiosis. Essential for normal life progression and reproduction is correct chromosome segregation during mitosis and meiosis. Defects in the division program lead to aneuploidy, which in turn leads to birth defects, miscarriages or cancer. Even thou, researchers invented much about the regulation of the cell cycle, there is still long way to understand the complexity of the regulatory machineries that ensure proper segregation of chromosomes. In this paper we would like to describe techniques and materials we use for our studies on chromosome segregation in the model organism Schizosaccharomyces pombe.

  14. A Spatial Control for Correct Timing of Gene Expression during the Escherichia coli Cell Cycle

    Directory of Open Access Journals (Sweden)

    Yuan Yao

    2016-12-01

    Full Text Available Temporal transcriptions of genes are achieved by different mechanisms such as dynamic interaction of activator and repressor proteins with promoters, and accumulation and/or degradation of key regulators as a function of cell cycle. We find that the TorR protein localizes to the old poles of the Escherichia coli cells, forming a functional focus. The TorR focus co-localizes with the nucleoid in a cell-cycle-dependent manner, and consequently regulates transcription of a number of genes. Formation of one TorR focus at the old poles of cells requires interaction with the MreB and DnaK proteins, and ATP, suggesting that TorR delivery requires cytoskeleton organization and ATP. Further, absence of the protein–protein interactions and ATP leads to loss in function of TorR as a transcription factor. We propose a mechanism for timing of cell-cycle-dependent gene transcription, where a transcription factor interacts with its target genes during a specific period of the cell cycle by limiting its own spatial distribution.

  15. Dual RNA-seq transcriptional analysis of wheat roots colonized by Azospirillum brasilense reveals up-regulation of nutrient acquisition and cell cycle genes.

    Science.gov (United States)

    Camilios-Neto, Doumit; Bonato, Paloma; Wassem, Roseli; Tadra-Sfeir, Michelle Z; Brusamarello-Santos, Liziane C C; Valdameri, Glaucio; Donatti, Lucélia; Faoro, Helisson; Weiss, Vinicius A; Chubatsu, Leda S; Pedrosa, Fábio O; Souza, Emanuel M

    2014-05-16

    The rapid growth of the world's population demands an increase in food production that no longer can be reached by increasing amounts of nitrogenous fertilizers. Plant growth promoting bacteria (PGPB) might be an alternative to increase nitrogenous use efficiency (NUE) in important crops such wheat. Azospirillum brasilense is one of the most promising PGPB and wheat roots colonized by A. brasilense is a good model to investigate the molecular basis of plant-PGPB interaction including improvement in plant-NUE promoted by PGPB. We performed a dual RNA-Seq transcriptional profiling of wheat roots colonized by A. brasilense strain FP2. cDNA libraries from biological replicates of colonized and non-inoculated wheat roots were sequenced and mapped to wheat and A. brasilense reference sequences. The unmapped reads were assembled de novo. Overall, we identified 23,215 wheat expressed ESTs and 702 A. brasilense expressed transcripts. Bacterial colonization caused changes in the expression of 776 wheat ESTs belonging to various functional categories, ranging from transport activity to biological regulation as well as defense mechanism, production of phytohormones and phytochemicals. In addition, genes encoding proteins related to bacterial chemotaxi, biofilm formation and nitrogen fixation were highly expressed in the sub-set of A. brasilense expressed genes. PGPB colonization enhanced the expression of plant genes related to nutrient up-take, nitrogen assimilation, DNA replication and regulation of cell division, which is consistent with a higher proportion of colonized root cells in the S-phase. Our data support the use of PGPB as an alternative to improve nutrient acquisition in important crops such as wheat, enhancing plant productivity and sustainability.

  16. The cell cycle inhibitor p27Kip¹ controls self-renewal and pluripotency of human embryonic stem cells by regulating the cell cycle, Brachyury and Twist.

    Science.gov (United States)

    Menchón, Cristina; Edel, Michael J; Izpisua Belmonte, Juan Carlos

    2011-05-01

    The continued turn over of human embryonic stem cells (hESC) while maintaining an undifferentiated state is dependent on the regulation of the cell cycle. Here we asked the question if a single cell cycle gene could regulate the self-renewal or pluripotency properties of hESC. We identified that the protein expression of the p27(Kip)¹ cell cycle inhibitor is low in hESC cells and increased with differentiation. By adopting a gain and loss of function strategy we forced or reduced its expression in undifferentiating conditions to define its functional role in self-renewal and pluripotency. Using undifferentiation conditions, overexpression of p27(Kip)¹ in hESC lead to a G₁phase arrest with an enlarged and flattened hESC morphology and consequent loss of self-renewal ability. Loss of p27(Kip)¹ caused an elongated/scatter cell-like phenotype involving up-regulation of Brachyury and Twist gene expression. We demonstrate the novel finding that p27(Kip)¹ protein occupies the Twist1 gene promoter and manipulation of p27(Kip)¹ by gain and loss of function is associated with Twist gene expression changes. These results define p27(Kip)¹ expression levels as critical for self-renewal and pluripotency in hESC and suggest a role for p27(Kip)¹ in controlling an epithelial to mesenchymal transition (EMT) in hESC.

  17. Proliferation marker pKi-67 affects the cell cycle in a self-regulated manner.

    Science.gov (United States)

    Schmidt, Mirko H H; Broll, Rainer; Bruch, Hans-Peter; Duchrow, Michael

    2002-01-01

    The proliferation marker pKi-67 is commonly used in research and pathology to detect proliferating cells. In a previous work, we found the protein to be associated with regulators of the cell cycle, controlling S-phase progression, as well as entry into and exit from mitosis. Here we investigate whether pKi-67 has a regulative effect on the cell cycle itself. For that purpose we cloned four fragments of pKi-67, together representing nearly the whole protein, and an N-terminal pKi-67 antisense oligonucleotide into a tetracycline inducible gene expression system. The sense fragments were C-terminally modified by addition of either a nuclear localization sequence (NLS) or a STOP codon to address the impact of their intracellular distribution. FACS based cell cycle analysis revealed that expression of nearly all pKi-67 domains and the antisense oligonucleotide led to a decreased amount of cells in S-phase and an increased number of cells in G(2)/M- and G(1)-phase. Subsequent analysis of the endogenous pKi-67 mRNA and protein levels revealed that the constructs with the most significant impact on the cell cycle were able to silence pKi-67 transcription as well. We conclude from the data that pKi-67 influences progression of S-phase and mitosis in a self-regulated manner and, therefore, effects the cell cycle checkpoints within both phases. Furthermore, we found pKi-67 mediates an anti-apoptotic effect on the cell and we verified that this marker, although it is a potential ribosomal catalyst, is not expressed in differentiated tissues with a high transcriptional activity. Copyright 2002 Wiley-Liss, Inc.

  18. Cell cycle regulation in human embryonic stem cells: links to adaptation to cell culture.

    Science.gov (United States)

    Barta, Tomas; Dolezalova, Dasa; Holubcova, Zuzana; Hampl, Ales

    2013-03-01

    Cell cycle represents not only a tightly orchestrated mechanism of cell replication and cell division but it also plays an important role in regulation of cell fate decision. Particularly in the context of pluripotent stem cells or multipotent progenitor cells, regulation of cell fate decision is of paramount importance. It has been shown that human embryonic stem cells (hESCs) show unique cell cycle characteristics, such as short doubling time due to abbreviated G1 phase; these properties change with the onset of differentiation. This review summarizes the current understanding of cell cycle regulation in hESCs. We discuss cell cycle properties as well as regulatory machinery governing cell cycle progression of undifferentiated hESCs. Additionally, we provide evidence that long-term culture of hESCs is accompanied by changes in cell cycle properties as well as configuration of several cell cycle regulatory molecules.

  19. Cell Cycle Regulates Nuclear Stability of AID and Determines the Cellular Response to AID.

    Directory of Open Access Journals (Sweden)

    Quy Le

    2015-09-01

    Full Text Available AID (Activation Induced Deaminase deaminates cytosines in DNA to initiate immunoglobulin gene diversification and to reprogram CpG methylation in early development. AID is potentially highly mutagenic, and it causes genomic instability evident as translocations in B cell malignancies. Here we show that AID is cell cycle regulated. By high content screening microscopy, we demonstrate that AID undergoes nuclear degradation more slowly in G1 phase than in S or G2-M phase, and that mutations that affect regulatory phosphorylation or catalytic activity can alter AID stability and abundance. We directly test the role of cell cycle regulation by fusing AID to tags that destabilize nuclear protein outside of G1 or S-G2/M phases. We show that enforced nuclear localization of AID in G1 phase accelerates somatic hypermutation and class switch recombination, and is well-tolerated; while nuclear AID compromises viability in S-G2/M phase cells. We identify AID derivatives that accelerate somatic hypermutation with minimal impact on viability, which will be useful tools for engineering genes and proteins by iterative mutagenesis and selection. Our results further suggest that use of cell cycle tags to regulate nuclear stability may be generally applicable to studying DNA repair and to engineering the genome.

  20. RNA interference regulates the cell cycle checkpoint through the RNA export factor, Ptr1, in fission yeast

    Energy Technology Data Exchange (ETDEWEB)

    Iida, Tetsushi, E-mail: tiida@nig.ac.jp [Division of Cytogenetics, National Institute of Genetics, Mishima, 1111 Yata, Mishima 411-8540 (Japan); The Graduate University for Advanced Studies, Sokendai, Mishima, 1111 Yata, Mishima 411-8540 (Japan); Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), 4-1-8, Honcho, Kawaguchi-shi, Saitama 332-0012 (Japan); Iida, Naoko [Division of Mutagenesis, National Institute of Genetics, Mishima, 1111 Yata, Mishima 411-8540 (Japan); Tsutsui, Yasuhiro [Department of Life Science, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Nagatsuda-cho, Midori-ku, Yokohama 226-8501 (Japan); Yamao, Fumiaki [Division of Mutagenesis, National Institute of Genetics, Mishima, 1111 Yata, Mishima 411-8540 (Japan); The Graduate University for Advanced Studies, Sokendai, Mishima, 1111 Yata, Mishima 411-8540 (Japan); Kobayashi, Takehiko [Division of Cytogenetics, National Institute of Genetics, Mishima, 1111 Yata, Mishima 411-8540 (Japan); The Graduate University for Advanced Studies, Sokendai, Mishima, 1111 Yata, Mishima 411-8540 (Japan)

    2012-10-12

    Highlights: Black-Right-Pointing-Pointer RNAi is linked to the cell cycle checkpoint in fission yeast. Black-Right-Pointing-Pointer Ptr1 co-purifies with Ago1. Black-Right-Pointing-Pointer The ptr1-1 mutation impairs the checkpoint but does not affect gene silencing. Black-Right-Pointing-Pointer ago1{sup +} and ptr1{sup +} regulate the cell cycle checkpoint via the same pathway. Black-Right-Pointing-Pointer Mutations in ago1{sup +} and ptr1{sup +} lead to the nuclear accumulation of poly(A){sup +} RNAs. -- Abstract: Ago1, an effector protein of RNA interference (RNAi), regulates heterochromatin silencing and cell cycle arrest in fission yeast. However, the mechanism by which Ago1 controls cell cycle checkpoint following hydroxyurea (HU) treatment has not been elucidated. In this study, we show that Ago1 and other RNAi factors control cell cycle checkpoint following HU treatment via a mechanism independent of silencing. While silencing requires dcr1{sup +}, the overexpression of ago1{sup +} alleviated the cell cycle defect in dcr1{Delta}. Ago1 interacted with the mRNA export factor, Ptr1. The ptr1-1 mutation impaired cell cycle checkpoint but gene silencing was unaffected. Genetic analysis revealed that the regulation of cell cycle checkpoint by ago1{sup +} is dependent on ptr1{sup +}. Nuclear accumulation of poly(A){sup +} RNAs was detected in mutants of ago1{sup +} and ptr1{sup +}, suggesting there is a functional link between the cell cycle checkpoint and RNAi-mediated RNA quality control.

  1. Cell cycle-regulated expression of mammalian CDC6 is dependent on E2F

    DEFF Research Database (Denmark)

    Hateboer, G; Wobst, A; Petersen, B O

    1998-01-01

    The E2F transcription factors are essential regulators of cell growth in multicellular organisms, controlling the expression of a number of genes whose products are involved in DNA replication and cell proliferation. In Saccharomyces cerevisiae, the MBF and SBF transcription complexes have...... of this gene is dependent on E2F. In vivo footprinting data demonstrate that the identified E2F sites are occupied in resting cells and in exponentially growing cells, suggesting that E2F is responsible for downregulating the promoter in early phases of the cell cycle and the subsequent upregulation when cells...

  2. Molecular machinery of signal transduction and cell cycle regulation in Plasmodium

    OpenAIRE

    Koyama, Fernanda C.; Chakrabarti, Debopam; Garcia, Célia R.S.

    2009-01-01

    The regulation of the Plasmodium cell cycle is not understood. Although the Plasmodium falciparum genome is completely sequenced, about 60% of the predicted proteins share little or no sequence similarity with other eukaryotes. This feature impairs the identification of important proteins participating in the regulation of the cell cycle. There are several open questions that concern cell cycle progression in malaria parasites, including the mechanism by which multiple nuclear divisions is co...

  3. Impact of cycling cells and cell cycle regulation on Hydra regeneration.

    Science.gov (United States)

    Buzgariu, Wanda; Wenger, Yvan; Tcaciuc, Nina; Catunda-Lemos, Ana-Paula; Galliot, Brigitte

    2018-01-15

    Hydra tissues are made from three distinct populations of stem cells that continuously cycle and pause in G2 instead of G1. To characterize the role of cell proliferation after mid-gastric bisection, we have (i) used flow cytometry and classical markers to monitor cell cycle modulations, (ii) quantified the transcriptomic regulations of 202 genes associated with cell proliferation during head and foot regeneration, and (iii) compared the impact of anti-proliferative treatments on regeneration efficiency. We confirm two previously reported events: an early mitotic wave in head-regenerating tips, when few cell cycle genes are up-regulated, and an early-late wave of proliferation on the second day, preceded by the up-regulation of 17 cell cycle genes. These regulations appear more intense after mid-gastric bisection than after decapitation, suggesting a position-dependent regulation of cell proliferation during head regeneration. Hydroxyurea, which blocks S-phase progression, delays head regeneration when applied before but not after bisection. This result is consistent with the fact that the Hydra central region is enriched in G2-paused adult stem cells, poised to divide upon injury, thus forming a necessary constitutive pro-blastema. However a prolonged exposure to hydroxyurea does not block regeneration as cells can differentiate apical structures without traversing S-phase, and also escape in few days the hydroxyurea-induced S-phase blockade. Thus Hydra head regeneration, which is a fast event, is highly plastic, relying on large stocks of adult stem cells paused in G2 at amputation time, which immediately divide to proliferate and/or differentiate apical structures even when S-phase is blocked. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  4. Protein kinase C signaling and cell cycle regulation

    OpenAIRE

    Black, Adrian R.; Black, Jennifer D.

    2013-01-01

    A link between T cell proliferation and the protein kinase C (PKC) family of serine/threonine kinases has been recognized for about thirty years. However, despite the wealth of information on PKC-mediated control of T cell activation, understanding of the effects of PKCs on the cell cycle machinery in this cell type remains limited. Studies in other systems have revealed important cell cycle-specific effects of PKC signaling that can either positively or negatively impact proliferation. Th...

  5. Overexpression of transcription factor Sp1 leads to gene expression perturbations and cell cycle inhibition.

    Directory of Open Access Journals (Sweden)

    Emmanuelle Deniaud

    Full Text Available BACKGROUND: The ubiquitous transcription factor Sp1 regulates the expression of a vast number of genes involved in many cellular functions ranging from differentiation to proliferation and apoptosis. Sp1 expression levels show a dramatic increase during transformation and this could play a critical role for tumour development or maintenance. Although Sp1 deregulation might be beneficial for tumour cells, its overexpression induces apoptosis of untransformed cells. Here we further characterised the functional and transcriptional responses of untransformed cells following Sp1 overexpression. METHODOLOGY AND PRINCIPAL FINDINGS: We made use of wild-type and DNA-binding-deficient Sp1 to demonstrate that the induction of apoptosis by Sp1 is dependent on its capacity to bind DNA. Genome-wide expression profiling identified genes involved in cancer, cell death and cell cycle as being enriched among differentially expressed genes following Sp1 overexpression. In silico search to determine the presence of Sp1 binding sites in the promoter region of modulated genes was conducted. Genes that contained Sp1 binding sites in their promoters were enriched among down-regulated genes. The endogenous sp1 gene is one of the most down-regulated suggesting a negative feedback loop induced by overexpressed Sp1. In contrast, genes containing Sp1 binding sites in their promoters were not enriched among up-regulated genes. These results suggest that the transcriptional response involves both direct Sp1-driven transcription and indirect mechanisms. Finally, we show that Sp1 overexpression led to a modified expression of G1/S transition regulatory genes such as the down-regulation of cyclin D2 and the up-regulation of cyclin G2 and cdkn2c/p18 expression. The biological significance of these modifications was confirmed by showing that the cells accumulated in the G1 phase of the cell cycle before the onset of apoptosis. CONCLUSION: This study shows that the binding to DNA

  6. Impaired Cell Cycle Regulation in a Natural Equine Model of Asthma.

    Directory of Open Access Journals (Sweden)

    Alicja Pacholewska

    Full Text Available Recurrent airway obstruction (RAO is a common and potentially debilitating lower airway disease in horses, which shares many similarities with human asthma. In susceptible horses RAO exacerbation is caused by environmental allergens and irritants present in hay dust. The objective of this study was the identification of genes and pathways involved in the pathology of RAO by global transcriptome analyses in stimulated peripheral blood mononuclear cells (PBMCs. We performed RNA-seq on PBMCs derived from 40 RAO affected and 45 control horses belonging to three cohorts of Warmblood horses: two half-sib families and one group of unrelated horses. PBMCs were stimulated with hay dust extract, lipopolysaccharides, a recombinant parasite antigen, or left unstimulated. The total dataset consisted of 561 individual samples. We detected significant differences in the expression profiles between RAO and control horses. Differential expression (DE was most marked upon stimulation with hay dust extract. An important novel finding was a strong upregulation of CXCL13 together with many genes involved in cell cycle regulation in stimulated samples from RAO affected horses, in addition to changes in the expression of several HIF-1 transcription factor target genes. The RAO condition alters systemic changes observed as differential expression profiles of PBMCs. Those changes also depended on the cohort and stimulation of the samples and were dominated by genes involved in immune cell trafficking, development, and cell cycle regulation. Our findings indicate an important role of CXCL13, likely macrophage or Th17 derived, and the cell cycle regulator CDC20 in the immune response in RAO.

  7. AIB1 regulates the ovarian cancer cell cycle through TUG1.

    Science.gov (United States)

    Li, L; Gan, Z-H; Qin, L; Jiao, S-H; Shi, Y

    2017-12-01

    To explore the mechanism of amplified in breast cancer 1 (AIB1) to promote ovarian cancer progress. Cor correlation analysis was performed to obtain the top 100 lncRNAs that were positively correlated with AIB1. The relationship of taurine upregulated gene 1 (TUG1) and clinicopathological characteristics. Moreover, Gene Ontology (GO) and Gene Set Enrichment Analysis (GSEA) were performed to predict the biological process where TUG1 may be involved in. At last, Cell Counting Kit-8 (CCK-8), colon formation and flow cytometry were conducted to explore the biological process that TUG1 may influence. Meanwhile, Western blot was performed to explore the mechanism of TUG1. In this study, it was found that P73 antisense RNA 1T (TP73-AS1), LINC00654 and TUG1 had the tumor-promoting effect in the top 100 lncRNAs that were positively correlated with AIB1. The expression level of TUG1 was significantly decreased after intervention of AIB1. Then, the clinical data were analyzed and the results showed that TUG1 was related to the tumor residue, tumor staging, tumor grade and lymph node metastasis. Moreover, the bioinformatics analysis revealed that TUG1 was mainly involved in the regulation of cell cycle. After intervention in TUG1, it was found that the cell proliferation capacity was significantly decreased, and the cell cycle was arrested in G1 phase. Finally, Western blot revealed that the expressions of G1 phase-related proteins were significantly changed. This study indicated that AIB1 regulates the cycle of ovarian cancer cells through TUG1. This study proved that AIB1 can regulate the cell cycle through regulating TUG1.

  8. Feedback loops and reciprocal regulation: recurring motifs in the systems biology of the cell cycle

    OpenAIRE

    Ferrell, James E.

    2013-01-01

    The study of eukaryotic cell cycle regulation over the last several decades has led to a remarkably detailed understanding of the complex regulatory system that drives this fundamental process. This allows us to now look for recurring motifs in the regulatory system. Among these are negative feedback loops, which underpin checkpoints and generate cell cycle oscillations; positive feedback loops, which promote oscillations and make cell cycle transitions switch-like and unidirectional; and rec...

  9. Evolution of cell cycle control: same molecular machines, different regulation

    DEFF Research Database (Denmark)

    de Lichtenberg, Ulrik; Jensen, Thomas Skøt; Brunak, Søren

    2007-01-01

    Decades of research has together with the availability of whole genomes made it clear that many of the core components involved in the cell cycle are conserved across eukaryotes, both functionally and structurally. These proteins are organized in complexes and modules that are activated or deacti......Decades of research has together with the availability of whole genomes made it clear that many of the core components involved in the cell cycle are conserved across eukaryotes, both functionally and structurally. These proteins are organized in complexes and modules that are activated...... for assembling the same molecular machines just in time for action....

  10. Cell cycle gene expression networks discovered using systems biology: Significance in carcinogenesis

    Science.gov (United States)

    Scott, RE; Ghule, PN; Stein, JL; Stein, GS

    2015-01-01

    The early stages of carcinogenesis are linked to defects in the cell cycle. A series of cell cycle checkpoints are involved in this process. The G1/S checkpoint that serves to integrate the control of cell proliferation and differentiation is linked to carcinogenesis and the mitotic spindle checkpoint with the development of chromosomal instability. This paper presents the outcome of systems biology studies designed to evaluate if networks of covariate cell cycle gene transcripts exist in proliferative mammalian tissues including mice, rats and humans. The GeneNetwork website that contains numerous gene expression datasets from different species, sexes and tissues represents the foundational resource for these studies (www.genenetwork.org). In addition, WebGestalt, a gene ontology tool, facilitated the identification of expression networks of genes that co-vary with key cell cycle targets, especially Cdc20 and Plk1 (www.bioinfo.vanderbilt.edu/webgestalt). Cell cycle expression networks of such covariate mRNAs exist in multiple proliferative tissues including liver, lung, pituitary, adipose and lymphoid tissues among others but not in brain or retina that have low proliferative potential. Sixty-three covariate cell cycle gene transcripts (mRNAs) compose the average cell cycle network with p = e−13 to e−36. Cell cycle expression networks show species, sex and tissue variability and they are enriched in mRNA transcripts associated with mitosis many of which are associated with chromosomal instability. PMID:25808367

  11. Macrophage/epithelium cross-talk regulates cell cycle progression and migration in pancreatic progenitors.

    Directory of Open Access Journals (Sweden)

    Kristin Mussar

    Full Text Available Macrophages populate the mesenchymal compartment of all organs during embryogenesis and have been shown to support tissue organogenesis and regeneration by regulating remodeling of the extracellular microenvironment. Whether this mesenchymal component can also dictate select developmental decisions in epithelia is unknown. Here, using the embryonic pancreatic epithelium as model system, we show that macrophages drive the epithelium to execute two developmentally important choices, i.e. the exit from cell cycle and the acquisition of a migratory phenotype. We demonstrate that these developmental decisions are effectively imparted by macrophages activated toward an M2 fetal-like functional state, and involve modulation of the adhesion receptor NCAM and an uncommon "paired-less" isoform of the transcription factor PAX6 in the epithelium. Over-expression of this PAX6 variant in pancreatic epithelia controls both cell motility and cell cycle progression in a gene-dosage dependent fashion. Importantly, induction of these phenotypes in embryonic pancreatic transplants by M2 macrophages in vivo is associated with an increased frequency of endocrine-committed cells emerging from ductal progenitor pools. These results identify M2 macrophages as key effectors capable of coordinating epithelial cell cycle withdrawal and cell migration, two events critical to pancreatic progenitors' delamination and progression toward their differentiated fates.

  12. Macrophage/epithelium cross-talk regulates cell cycle progression and migration in pancreatic progenitors.

    Science.gov (United States)

    Mussar, Kristin; Tucker, Andrew; McLennan, Linsey; Gearhart, Addie; Jimenez-Caliani, Antonio J; Cirulli, Vincenzo; Crisa, Laura

    2014-01-01

    Macrophages populate the mesenchymal compartment of all organs during embryogenesis and have been shown to support tissue organogenesis and regeneration by regulating remodeling of the extracellular microenvironment. Whether this mesenchymal component can also dictate select developmental decisions in epithelia is unknown. Here, using the embryonic pancreatic epithelium as model system, we show that macrophages drive the epithelium to execute two developmentally important choices, i.e. the exit from cell cycle and the acquisition of a migratory phenotype. We demonstrate that these developmental decisions are effectively imparted by macrophages activated toward an M2 fetal-like functional state, and involve modulation of the adhesion receptor NCAM and an uncommon "paired-less" isoform of the transcription factor PAX6 in the epithelium. Over-expression of this PAX6 variant in pancreatic epithelia controls both cell motility and cell cycle progression in a gene-dosage dependent fashion. Importantly, induction of these phenotypes in embryonic pancreatic transplants by M2 macrophages in vivo is associated with an increased frequency of endocrine-committed cells emerging from ductal progenitor pools. These results identify M2 macrophages as key effectors capable of coordinating epithelial cell cycle withdrawal and cell migration, two events critical to pancreatic progenitors' delamination and progression toward their differentiated fates.

  13. Regulation of cell cycle progression by cell-cell and cell-matrix forces

    NARCIS (Netherlands)

    Uroz, Marina; Wistorf, Sabrina; Serra-Picamal, Xavier; Conte, Vito; Sales-Pardo, Marta; Roca-Cusachs, Pere; Guimerà, Roger; Trepat, Xavier

    2018-01-01

    It has long been proposed that the cell cycle is regulated by physical forces at the cell-cell and cell-extracellular matrix (ECM) interfaces 1-12 . However, the evolution of these forces during the cycle has never been measured in a tissue, and whether this evolution affects cell cycle progression

  14. Expression profile of cell cycle genes in the fish CATLA CATLA (Ham.) exposed to gamma radiation

    International Nuclear Information System (INIS)

    Anbumani, S.; Mohankumar Mary, N.

    2012-01-01

    The International Commission on Radiological Protection (ICRP) emphasized the need to protect non-human biota from the potential effects of ionizing radiation and proposed to include molecular effects such as DNA damage as endpoints. Molecular effects of ionizing radiation exposure in representative non-humans are largely unexplored and sufficient data is not available in fishes. Gene expression is a fast and sensitive end point in detecting the molecular cues as a result of ionizing radiation exposure in a wide variety of aquatic organisms under suspected environmental contamination. Exposure to ionizing radiation transiently alters gene expression profiles as cells regulate certain genes to protect cellular structures and repair damage. The present study focused on genes like Gadd45á, Cdk1 and Bcl-2 in DNA damage repair and cell cycle machinery and its implication as molecular markers of radiation exposure. This study is first of its kind showing the in vivo expression profile of cell cycle genes in fish exposed to gamma radiation. Although this preliminary investigation points to certain molecular markers of ionizing radiation, elaborate studies with various doses and dose-rates are required before these markers find application as prospective molecular markers in aquatic radiation biodosimetry

  15. Transcription of ribosomal RNA genes is initiated in the third cell cycle of bovine embryos

    DEFF Research Database (Denmark)

    Jakobsen, Anne Sørig; Avery, Birthe; Dieleman, Steph J.

    2006-01-01

    Transcription from the embryos own ribosomal genes is initiated in most species at the same time as the maternal-embryonic transition. Recently data have indicated that a minor activation may take place during the third embryonic cell cycle in the bovine, one cell cycle before the major activation...

  16. UBE2C Is a Transcriptional Target of the Cell Cycle Regulator FOXM1

    Directory of Open Access Journals (Sweden)

    Pedro Nicolau-Neto

    2018-03-01

    Full Text Available FOXM1 (forkhead box protein M1 is a transcription factor that participates in all stages of tumor development, mainly through the control of cell cycle and proliferation, regulating the expression of genes involved in G1/S and G2/M transition and M phase progression. The ubiquitin conjugating enzyme E2 (UBE2C is a member of the anaphase promoting complex/cyclosome, promoting the degradation of several target proteins along cell cycle progression, during metaphase/anaphase transition. FOXM1 and UBE2C have been found overexpressed in a wide range of different solid tumors. Therefore, the aim of this study was to investigate whether UBE2C is a transcriptional target of FOXM1, using esophageal squamous cell carcinoma (ESCC as a model, in addition to several cancer-deposited data. Our results show that FOXM1 and UBE2C expression present a positive correlation in normal tissues and in 25 distinct tumor types, including ESCC, where these genes are overexpressed. Moreover, FOXM1 binds to UBE2C promoter region in ESCC cell line and transcriptionally activates it, leading to UBE2C upregulation. In conclusion, this study provides evidences that FOXM1 transcriptionally regulates UBE2C expression in ESCC and their deregulation may be a general phenomenon in human neoplasias.

  17. UV-induced changes in cell cycle and gene expression within rabbit lens epithelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Sidjanin, D. [Northern Illinois Univ., De Kalb, IL (United States). Dept. of Biological Sciences; Grdina, D. [Argonne National Lab., IL (United States); Woloschak, G.E. [Northern Illinois Univ., De Kalb, IL (United States). Dept. of Biological Sciences

    1994-11-01

    Damage to lens epithelial cells is a probable initiation process in cataract formation induced by ultraviolet radiation. These experiments investigated the ability of 254 nm radiation on cell cycle progression and gene expression in rabbit lens epithelial cell line N/N1003A. No changes in expression of c-fos, c-jun, alpha- tubulin, or vimentin was observed following UV exposure. Using flow cytometry, an accumulation of cells in G1/S phase of the cell cycle 1 hr following exposure. The observed changes in gene expression, especially the decreased histone transcripts reported here may play a role in UV induced inhibition of cell cycle progression.

  18. Redistribution of cell cycle by arsenic trioxide is associated with demethylation and expression changes of cell cycle related genes in acute promyelocytic leukemia cell line (NB4).

    Science.gov (United States)

    Hassani, Saeed; Khaleghian, Ali; Ahmadian, Shahin; Alizadeh, Shaban; Alimoghaddam, Kamran; Ghavamzadeh, Ardeshir; Ghaffari, Seyed H

    2018-01-01

    PML-RARα perturbs the normal epigenetic setting, which is essential to oncogenic transformation in acute promyelocytic leukemia (APL). Transcription induction and recruitment of DNA methyltransferases (DNMTs) by PML-RARα and subsequent hypermethylation are components of this perturbation. Arsenic trioxide (ATO), an important drug in APL therapy, concurrent with degradation of PML-RARα induces cell cycle change and apoptosis. How ATO causes cell cycle alteration has remained largely unexplained. Here, we investigated DNA methylation patterns of cell cycle regulatory genes promoters, the effects of ATO on the methylated genes and cell cycle distribution in an APL cell line, NB4. Analysis of promoter methylation status of 22 cell cycle related genes in NB4 revealed that CCND1, CCNE1, CCNF, CDKN1A, GADD45α, and RBL1 genes were methylated 60.7, 84.6, 58.6, 8.7, 33.4, and 73.7%, respectively, that after treatment with 2 μM ATO for 48 h, turn into 0.6, 13.8, 0.1, 6.6, 10.7, and 54.5% methylated. ATO significantly reduced the expression of DNMT1, 3A, and 3B. ATO induced the expression of CCND1, CCNE1, and GADD45α genes, suppressed the expression of CCNF and CDKN1A genes, which were consistent with decreased number of cells in G1 and S phases and increased number of cells in G2/M phase. In conclusion, demethylation and alteration in the expression level of the cell cycle related genes may be possible mechanisms in ATO-induced cell cycle arrest in APL cells. It may suggest that ATO by demethylation of CCND1 and CCNE1 and their transcriptional activation accelerates G1 and S transition into the G2/M cell cycle arrest.

  19. Cell cycle genes and ovarian cancer susceptibility: a tagSNP analysis

    DEFF Research Database (Denmark)

    Cunningham, J M; Vierkant, R A; Sellers, T A

    2009-01-01

    BACKGROUND: Dysregulation of the cell cycle is a hallmark of many cancers including ovarian cancer, a leading cause of gynaecologic cancer mortality worldwide. METHODS: We examined single nucleotide polymorphisms (SNPs) (n=288) from 39 cell cycle regulation genes, including cyclins, cyclin......-dependent kinases (CDKs) and CDK inhibitors, in a two-stage study. White, non-Hispanic cases (n=829) and ovarian cancer-free controls (n=941) were genotyped using an Illumina assay. RESULTS: Eleven variants in nine genes (ABL1, CCNB2, CDKN1A, CCND3, E2F2, CDK2, E2F3, CDC2, and CDK7) were associated with risk...... of ovarian cancer in at least one genetic model. Seven SNPs were then assessed in four additional studies with 1689 cases and 3398 controls. Association between risk of ovarian cancer and ABL1 rs2855192 found in the original population [odds ratio, OR(BB vs AA) 2.81 (1.29-6.09), P=0.01] was also observed...

  20. Regulation of cell cycle checkpoint kinase WEE1 by miR-195 in malignant melanoma.

    Science.gov (United States)

    Bhattacharya, A; Schmitz, U; Wolkenhauer, O; Schönherr, M; Raatz, Y; Kunz, M

    2013-06-27

    WEE1 kinase has been described as a major gate keeper at the G2 cell cycle checkpoint and to be involved in tumour progression in different malignant tumours. Here we analysed the expression levels of WEE1 in a series of melanoma patient samples and melanoma cell lines using immunoblotting, quantitative real-time PCR and immunohistochemistry. WEE1 expression was significantly downregulated in patient samples of metastatic origin as compared with primary melanomas and in melanoma cell lines of high aggressiveness as compared with cell lines of low aggressiveness. Moreover, there was an inverse correlation between the expression of WEE1 and WEE1-targeting microRNA miR-195. Further analyses showed that transfection of melanoma cell lines with miR-195 indeed reduced WEE1 mRNA and protein expression in these cells. Reporter gene analysis confirmed direct targeting of the WEE1 3' untranslated region (3'UTR) by miR-195. Overexpression of miR-195 in SK-Mel-28 melanoma cells was accompanied by WEE1 reduction and significantly reduced stress-induced G2-M cell cycle arrest, which could be restored by stable overexpression of WEE1. Moreover, miR-195 overexpression and WEE1 knockdown, respectively, increased melanoma cell proliferation. miR-195 overexpression also enhanced migration and invasiveness of melanoma cells. Taken together, the present study shows that WEE1 expression in malignant melanoma is directly regulated by miR-195. miR-195-mediated downregulation of WEE1 in metastatic lesions may help to overcome cell cycle arrest under stress conditions in the local tissue microenvironment to allow unrestricted growth of tumour cells.

  1. Regulation of the vertebrate cell cycle by the cdc2 protein kinase

    International Nuclear Information System (INIS)

    Draetta, G.; Brizuela, L.; Moran, B.; Beach, D.

    1988-01-01

    A homolog of the cdc2/CDC28 protein kinase of yeast is found in all vertebrate species that have been investigated. Human cdc2 exists as a complex with a 13-kD protein that is homologous to the suc1 gene product of fission yeast. In both human and fission yeast cells, the protein kinase also exists in a complex with a 62-kD polypeptide that has not been identified genetically but acts as a substrate in vitro. The authors have studied the properties of the protein kinase in rat and human cells, as well as in Xenopus eggs. They find that in baby rat kidney (BRK) cells, which are quiescent in cell culture, the cdc2 protein is not synthesized. However, synthesis is rapidly induced in response to proliferative activation by infection with adenovirus. In human HeLa cells, the protein kinase is present continuously. It behaves as a cell-cycle oscillator that is inactive in G 1 but displays maximal enzymatic activity during mitotic metaphase. These observations indicate that in a wide variety of vertebrate cells, the cdc2 protein kinase is involved in regulating mitosis. The authors' approach taken toward study of the cdc2 protein kinase highlights the possibilities that now exist for combining the advantages of ascomycete genetics with the cell-free systems of Xenopus and the biochemical advantages of tissue culture cells to investigate fundamental problems of the cell cycle

  2. Periodic expression of nuclear and mitochondrial DNA replication genes during the trypanosomatid cell cycle.

    Science.gov (United States)

    Pasion, S G; Brown, G W; Brown, L M; Ray, D S

    1994-12-01

    In trypanosomatids, DNA replication in the nucleus and in the single mitochondrion (or kinetoplast) initiates nearly simultaneously, suggesting that the DNA synthesis (S) phases of the nucleus and the mitochondrion are coordinately regulated. To investigate the basis for the temporal link between nuclear and mitochondrial DNA synthesis phases the expression of the genes encoding DNA ligase I, the 51 and 28 kDa subunits of replication protein A, dihydrofolate reductase and the mitochondrial type II topoisomerase were analyzed during the cell cycle progression of synchronous cultures of Crithidia fasciculata. These DNA replication genes were all expressed periodically, with peak mRNA levels occurring just prior to or at the peak of DNA synthesis in the synchronized cultures. A plasmid clone (pdN-1) in which TOP2, the gene encoding the mitochondrial topoisomerase, was disrupted by the insertion of a NEO drug-resistance cassette was found to express both a truncated TOP2 mRNA and a truncated topoisomerase polypeptide. The truncated mRNA was also expressed periodically coordinate with the expression of the endogenous TOP2 mRNA indicating that cis elements necessary for periodic expression are contained within cloned sequences. The expression of both TOP2 and nuclear DNA replication genes at the G1/S boundary suggests that regulated expression of these genes may play a role in coordinating nuclear and mitochondrial S phases in trypanosomatids.

  3. Candidate gene analysis using imputed genotypes: cell cycle single-nucleotide polymorphisms and ovarian cancer risk

    DEFF Research Database (Denmark)

    Goode, Ellen L; Fridley, Brooke L; Vierkant, Robert A

    2009-01-01

    Polymorphisms in genes critical to cell cycle control are outstanding candidates for association with ovarian cancer risk; numerous genes have been interrogated by multiple research groups using differing tagging single-nucleotide polymorphism (SNP) sets. To maximize information gleaned from......, and rs3212891; CDK2 rs2069391, rs2069414, and rs17528736; and CCNE1 rs3218036. These results exemplify the utility of imputation in candidate gene studies and lend evidence to a role of cell cycle genes in ovarian cancer etiology, suggest a reduced set of SNPs to target in additional cases and controls....

  4. Molecular machinery of signal transduction and cell cycle regulation in Plasmodium.

    Science.gov (United States)

    Koyama, Fernanda C; Chakrabarti, Debopam; Garcia, Célia R S

    2009-05-01

    The regulation of the Plasmodium cell cycle is not understood. Although the Plasmodium falciparum genome is completely sequenced, about 60% of the predicted proteins share little or no sequence similarity with other eukaryotes. This feature impairs the identification of important proteins participating in the regulation of the cell cycle. There are several open questions that concern cell cycle progression in malaria parasites, including the mechanism by which multiple nuclear divisions is controlled and how the cell cycle is managed in all phases of their complex life cycle. Cell cycle synchrony of the parasite population within the host, as well as the circadian rhythm of proliferation, are striking features of some Plasmodium species, the molecular basis of which remains to be elucidated. In this review we discuss the role of indole-related molecules as signals that modulate the cell cycle in Plasmodium and other eukaryotes, and we also consider the possible role of kinases in the signal transduction and in the responses it triggers.

  5. The cell cycle regulator protein P16 and the cellular senescence of dental follicle cells.

    Science.gov (United States)

    Morsczeck, Christian; Hullmann, Markus; Reck, Anja; Reichert, Torsten E

    2018-02-01

    Cellular senescence is a restricting factor for regenerative therapies with somatic stem cells. We showed previously that the onset of cellular senescence inhibits the osteogenic differentiation in stem cells of the dental follicle (DFCs), although the mechanism remains elusive. Two different pathways are involved in the induction of the cellular senescence, which are driven either by the cell cycle protein P21 or by the cell cycle protein P16. In this study, we investigated the expression of cell cycle proteins in DFCs after the induction of cellular senescence. The induction of cellular senescence was proved by an increased expression of β-galactosidase and an increased population doubling time after a prolonged cell culture. Cellular senescence regulated the expression of cell cycle proteins. The expression of cell cycle protein P16 was up-regulated, which correlates with the induction of cellular senescence markers in DFCs. However, the expression of cyclin-dependent kinases (CDK)2 and 4 and the expression of the cell cycle protein P21 were successively decreased in DFCs. In conclusion, our data suggest that a P16-dependent pathway drives the induction of cellular senescence in DFCs.

  6. Understanding cell cycle and cell death regulation provides novel weapons against human diseases.

    Science.gov (United States)

    Wiman, K G; Zhivotovsky, B

    2017-05-01

    Cell division, cell differentiation and cell death are the three principal physiological processes that regulate tissue homoeostasis in multicellular organisms. The growth and survival of cells as well as the integrity of the genome are regulated by a complex network of pathways, in which cell cycle checkpoints, DNA repair and programmed cell death have critical roles. Disruption of genomic integrity and impaired regulation of cell death may both lead to uncontrolled cell growth. Compromised cell death can also favour genomic instability. It is becoming increasingly clear that dysregulation of cell cycle and cell death processes plays an important role in the development of major disorders such as cancer, cardiovascular disease, infection, inflammation and neurodegenerative diseases. Research achievements in these fields have led to the development of novel approaches for treatment of various conditions associated with abnormalities in the regulation of cell cycle progression or cell death. A better understanding of how cellular life-and-death processes are regulated is essential for this development. To highlight these important advances, the Third Nobel Conference entitled 'The Cell Cycle and Cell Death in Disease' was organized at Karolinska Institutet in 2016. In this review we will summarize current understanding of cell cycle progression and cell death and discuss some of the recent advances in therapeutic applications in pathological conditions such as cancer, neurological disorders and inflammation. © 2017 The Association for the Publication of the Journal of Internal Medicine.

  7. Differential response of cell-cycle and cell-expansion regulators to heat stress in apple (Malus domestica) fruitlets.

    Science.gov (United States)

    Flaishman, Moshe A; Peles, Yuval; Dahan, Yardena; Milo-Cochavi, Shira; Frieman, Aviad; Naor, Amos

    2015-04-01

    Temperature is one of the most significant factors affecting physiological and biochemical aspects of fruit development. Current and progressing global warming is expected to change climate in the traditional deciduous fruit tree cultivation regions. In this study, 'Golden Delicious' trees, grown in a controlled environment or commercial orchard, were exposed to different periods of heat treatment. Early fruitlet development was documented by evaluating cell number, cell size and fruit diameter for 5-70 days after full bloom. Normal activities of molecular developmental and growth processes in apple fruitlets were disrupted under daytime air temperatures of 29°C and higher as a result of significant temporary declines in cell-production and cell-expansion rates, respectively. Expression screening of selected cell cycle and cell expansion genes revealed the influence of high temperature on genetic regulation of apple fruitlet development. Several core cell-cycle and cell-expansion genes were differentially expressed under high temperatures. While expression levels of B-type cyclin-dependent kinases and A- and B-type cyclins declined moderately in response to elevated temperatures, expression of several cell-cycle inhibitors, such as Mdwee1, Mdrbr and Mdkrps was sharply enhanced as the temperature rose, blocking the cell-cycle cascade at the G1/S and G2/M transition points. Moreover, expression of several expansin genes was associated with high temperatures, making them potentially useful as molecular platforms to enhance cell-expansion processes under high-temperature regimes. Understanding the molecular mechanisms of heat tolerance associated with genes controlling cell cycle and cell expansion may lead to the development of novel strategies for improving apple fruit productivity under global warming. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  8. Functional interrelationship between TFII-I and E2F transcription factors at specific cell cycle gene loci.

    Science.gov (United States)

    Shen, Yong; Nar, Rukiye; Fan, Alex X; Aryan, Mahmoud; Hossain, Mir A; Gurumurthy, Aishwarya; Wassel, Paul C; Tang, Ming; Lu, Jianrong; Strouboulis, John; Bungert, Jörg

    2018-01-01

    Transcription factor TFII-I is a multifunctional protein implicated in the regulation of cell cycle and stress-response genes. Previous studies have shown that a subset of TFII-I associated genomic sites contained DNA-binding motifs for E2F family transcription factors. We analyzed the co-association of TFII-I and E2Fs in more detail using bioinformatics, chromatin immunoprecipitation, and co-immunoprecipitation experiments. The data show that TFII-I interacts with E2F transcription factors. Furthermore, TFII-I, E2F4, and E2F6 interact with DNA-regulatory elements of several genes implicated in the regulation of the cell cycle, including DNMT1, HDAC1, CDKN1C, and CDC27. Inhibition of TFII-I expression led to a decrease in gene expression and in the association of E2F4 and E2F6 with these gene loci in human erythroleukemia K562 cells. Finally, TFII-I deficiency reduced the proliferation of K562 cells and increased the sensitivity toward doxorubicin toxicity. The results uncover novel interactions between TFII-I and E2Fs and suggest that TFII-I mediates E2F function at specific cell cycle genes. © 2017 Wiley Periodicals, Inc.

  9. Withaferin A and sulforaphane regulate breast cancer cell cycle progression through epigenetic mechanisms.

    Science.gov (United States)

    Royston, Kendra J; Paul, Bidisha; Nozell, Susan; Rajbhandari, Rajani; Tollefsbol, Trygve O

    2018-07-01

    Little is known about the effects of combinatorial dietary compounds on the regulation of epigenetic mechanisms involved in breast cancer prevention. The human diet consists of a multitude of components, and there is a need to elucidate how certain compounds interact in collaboration. Withaferin A (WA), found in the Indian winter cherry and documented as a DNA methyltransferase (DNMT) inhibitor, and sulforaphane (SFN), a well-known histone deacetylase (HDAC) inhibitor found in cruciferous vegetables, are two epigenetic modifying compounds that have only recently been studied in conjunction. The use of DNMT and HDAC inhibitors to reverse the malignant expression of certain genes in breast cancer has shown considerable promise. Previously, we found that SFN + WA synergistically promote breast cancer cell death. Herein, we determined that these compounds inhibit cell cycle progression from S to G2 phase in MDA-MB-231 and MCF-7 breast cancer. Furthermore, we demonstrate that this unique combination of epigenetic modifying compounds down-regulates the levels of Cyclin D1 and CDK4, and pRB; conversely, the levels of E2F mRNA and tumor suppressor p21 are increased independently of p53. We find these events coincide with an increase in unrestricted histone methylation. We propose SFN + WA-induced breast cancer cell death is attributed, in part, to epigenetic modifications that result in the modulated expression of key genes responsible for the regulation of cancer cell senescence. Copyright © 2018 Elsevier Inc. All rights reserved.

  10. Model-based deconvolution of cell cycle time-series data reveals gene expression details at high resolution.

    Directory of Open Access Journals (Sweden)

    Dan Siegal-Gaskins

    2009-08-01

    Full Text Available In both prokaryotic and eukaryotic cells, gene expression is regulated across the cell cycle to ensure "just-in-time" assembly of select cellular structures and molecular machines. However, present in all time-series gene expression measurements is variability that arises from both systematic error in the cell synchrony process and variance in the timing of cell division at the level of the single cell. Thus, gene or protein expression data collected from a population of synchronized cells is an inaccurate measure of what occurs in the average single-cell across a cell cycle. Here, we present a general computational method to extract "single-cell"-like information from population-level time-series expression data. This method removes the effects of 1 variance in growth rate and 2 variance in the physiological and developmental state of the cell. Moreover, this method represents an advance in the deconvolution of molecular expression data in its flexibility, minimal assumptions, and the use of a cross-validation analysis to determine the appropriate level of regularization. Applying our deconvolution algorithm to cell cycle gene expression data from the dimorphic bacterium Caulobacter crescentus, we recovered critical features of cell cycle regulation in essential genes, including ctrA and ftsZ, that were obscured in population-based measurements. In doing so, we highlight the problem with using population data alone to decipher cellular regulatory mechanisms and demonstrate how our deconvolution algorithm can be applied to produce a more realistic picture of temporal regulation in a cell.

  11. Copy Number Defects of G1-Cell Cycle Genes in Neuroblastoma are Frequent and Correlate with High Expression of E2F Target Genes and a Poor Prognosis

    NARCIS (Netherlands)

    Molenaar, Jan J.; Koster, Jan; Ebus, Marli E.; van Sluis, Peter; Westerhout, Ellen M.; de Preter, Katleen; Gisselsson, David; Øra, Ingrid; Speleman, Frank; Caron, Huib N.; Versteeg, Rogier

    2012-01-01

    The tightly controlled network of cell cycle genes consists of a core of cyclin dependent kinases (CDKs) that are activated by periodically expressed cyclins. The activity of the cyclin-CDK complexes is regulated by cyclin dependent kinase inhibitors (CDKIs) and multiple signal transduction routes

  12. Proposed megakaryocytic regulon of p53: the genes engaged to control cell cycle and apoptosis during megakaryocytic differentiation

    Science.gov (United States)

    Apostolidis, Pani A.; Lindsey, Stephan; Miller, William M.

    2012-01-01

    During endomitosis, megakaryocytes undergo several rounds of DNA synthesis without division leading to polyploidization. In primary megakaryocytes and in the megakaryocytic cell line CHRF, loss or knock-down of p53 enhances cell cycling and inhibits apoptosis, leading to increased polyploidization. To support the hypothesis that p53 suppresses megakaryocytic polyploidization, we show that stable expression of wild-type p53 in K562 cells (a p53-null cell line) attenuates the cells' ability to undergo polyploidization during megakaryocytic differentiation due to diminished DNA synthesis and greater apoptosis. This suggested that p53's effects during megakaryopoiesis are mediated through cell cycle- and apoptosis-related target genes, possibly by arresting DNA synthesis and promoting apoptosis. To identify candidate genes through which p53 mediates these effects, gene expression was compared between p53 knock-down (p53-KD) and control CHRF cells induced to undergo terminal megakaryocytic differentiation using microarray analysis. Among substantially downregulated p53 targets in p53-KD megakaryocytes were cell cycle regulators CDKN1A (p21) and PLK2, proapoptotic FAS, TNFRSF10B, CASP8, NOTCH1, TP53INP1, TP53I3, DRAM1, ZMAT3 and PHLDA3, DNA-damage-related RRM2B and SESN1, and actin component ACTA2, while antiapoptotic CKS1B, BCL2, GTSE1, and p53 family member TP63 were upregulated in p53-KD cells. Additionally, a number of cell cycle-related, proapoptotic, and cytoskeleton-related genes with known functions in megakaryocytes but not known to carry p53-responsive elements were differentially expressed between p53-KD and control CHRF cells. Our data support a model whereby p53 expression during megakaryopoiesis serves to control polyploidization and the transition from endomitosis to apoptosis by impeding cell cycling and promoting apoptosis. Furthermore, we identify a putative p53 regulon that is proposed to orchestrate these effects. PMID:22548738

  13. Nuclear receptor TLX regulates cell cycle progression in neural stem cells of the developing brain.

    Science.gov (United States)

    Li, Wenwu; Sun, Guoqiang; Yang, Su; Qu, Qiuhao; Nakashima, Kinichi; Shi, Yanhong

    2008-01-01

    TLX is an orphan nuclear receptor that is expressed exclusively in vertebrate forebrains. Although TLX is known to be expressed in embryonic brains, the mechanism by which it influences neural development remains largely unknown. We show here that TLX is expressed specifically in periventricular neural stem cells in embryonic brains. Significant thinning of neocortex was observed in embryonic d 14.5 TLX-null brains with reduced nestin labeling and decreased cell proliferation in the germinal zone. Cell cycle analysis revealed both prolonged cell cycles and increased cell cycle exit in TLX-null embryonic brains. Increased expression of a cyclin-dependent kinase inhibitor p21 and decreased expression of cyclin D1 provide a molecular basis for the deficiency of cell cycle progression in embryonic brains of TLX-null mice. Furthermore, transient knockdown of TLX by in utero electroporation led to precocious cell cycle exit and differentiation of neural stem cells followed by outward migration. Together these results indicate that TLX plays an important role in neural development by regulating cell cycle progression and exit of neural stem cells in the developing brain.

  14. Redox regulation of cell proliferation: Bioinformatics and redox proteomics approaches to identify redox-sensitive cell cycle regulators.

    Science.gov (United States)

    Foyer, Christine H; Wilson, Michael H; Wright, Megan H

    2018-03-29

    Plant stem cells are the foundation of plant growth and development. The balance of quiescence and division is highly regulated, while ensuring that proliferating cells are protected from the adverse effects of environment fluctuations that may damage the genome. Redox regulation is important in both the activation of proliferation and arrest of the cell cycle upon perception of environmental stress. Within this context, reactive oxygen species serve as 'pro-life' signals with positive roles in the regulation of the cell cycle and survival. However, very little is known about the metabolic mechanisms and redox-sensitive proteins that influence cell cycle progression. We have identified cysteine residues on known cell cycle regulators in Arabidopsis that are potentially accessible, and could play a role in redox regulation, based on secondary structure and solvent accessibility likelihoods for each protein. We propose that redox regulation may function alongside other known posttranslational modifications to control the functions of core cell cycle regulators such as the retinoblastoma protein. Since our current understanding of how redox regulation is involved in cell cycle control is hindered by a lack of knowledge regarding both which residues are important and how modification of those residues alters protein function, we discuss how critical redox modifications can be mapped at the molecular level. Crown Copyright © 2018. Published by Elsevier Inc. All rights reserved.

  15. Discrete gene replication events drive coupling between the cell cycle and circadian clocks.

    Science.gov (United States)

    Paijmans, Joris; Bosman, Mark; Ten Wolde, Pieter Rein; Lubensky, David K

    2016-04-12

    Many organisms possess both a cell cycle to control DNA replication and a circadian clock to anticipate changes between day and night. In some cases, these two rhythmic systems are known to be coupled by specific, cross-regulatory interactions. Here, we use mathematical modeling to show that, additionally, the cell cycle generically influences circadian clocks in a nonspecific fashion: The regular, discrete jumps in gene-copy number arising from DNA replication during the cell cycle cause a periodic driving of the circadian clock, which can dramatically alter its behavior and impair its function. A clock built on negative transcriptional feedback either phase-locks to the cell cycle, so that the clock period tracks the cell division time, or exhibits erratic behavior. We argue that the cyanobacterium Synechococcus elongatus has evolved two features that protect its clock from such disturbances, both of which are needed to fully insulate it from the cell cycle and give it its observed robustness: a phosphorylation-based protein modification oscillator, together with its accompanying push-pull read-out circuit that responds primarily to the ratios of different phosphoform concentrations, makes the clock less susceptible to perturbations in protein synthesis; the presence of multiple, asynchronously replicating copies of the same chromosome diminishes the effect of replicating any single copy of a gene.

  16. MMSET is dynamically regulated during cell-cycle progression and promotes normal DNA replication.

    Science.gov (United States)

    Evans, Debra L; Zhang, Haoxing; Ham, Hyoungjun; Pei, Huadong; Lee, SeungBaek; Kim, JungJin; Billadeau, Daniel D; Lou, Zhenkun

    2016-01-01

    The timely and precise duplication of cellular DNA is essential for maintaining genome integrity and is thus tightly-regulated. During mitosis and G1, the Origin Recognition Complex (ORC) binds to future replication origins, coordinating with multiple factors to load the minichromosome maintenance (MCM) complex onto future replication origins as part of the pre-replication complex (pre-RC). The pre-RC machinery, in turn, remains inactive until the subsequent S phase when it is required for replication fork formation, thereby initiating DNA replication. Multiple myeloma SET domain-containing protein (MMSET, a.k.a. WHSC1, NSD2) is a histone methyltransferase that is frequently overexpressed in aggressive cancers and is essential for normal human development. Several studies have suggested a role for MMSET in cell-cycle regulation; however, whether MMSET is itself regulated during cell-cycle progression has not been examined. In this study, we report that MMSET is degraded during S phase in a cullin-ring ligase 4-Cdt2 (CRL4(Cdt2)) and proteasome-dependent manner. Notably, we also report defects in DNA replication and a decreased association of pre-RC factors with chromatin in MMSET-depleted cells. Taken together, our results suggest a dynamic regulation of MMSET levels throughout the cell cycle, and further characterize the role of MMSET in DNA replication and cell-cycle progression.

  17. CAR-mediated repression of Foxo1 transcriptional activity regulates the cell cycle inhibitor p21 in mouse livers

    International Nuclear Information System (INIS)

    Kazantseva, Yuliya A.; Yarushkin, Andrei A.; Pustylnyak, Vladimir O.

    2014-01-01

    Highlights: • CAR activation decreased the level of Foxo1 in mouse livers. • CAR activation decreased the level of p21 in mouse livers. • CAR activation inhibited Foxo1 transcriptional activity in mouse livers. - Abstract: 1,4-Bis[2-(3,5-dichloropyridyloxy)]benzene (TCPOBOP), an agonist of constitutive androstane receptor (CAR), is a well-known strong primary chemical mitogen for the mouse liver. Despite extensive investigation of the role of CAR in the regulation of cell proliferation, our knowledge of the intricate mediating mechanism is incomplete. In this study, we demonstrated that long-term CAR activation by TCPOBOP increased liver-to-body weight ratio and decreased tumour suppressor Foxo1 expression and transcriptional activity, which were correlated with reduced expression of genes regulated by Foxo1, including the cell-cycle inhibitor Cdkn1a(p21), and upregulation of the cell-cycle regulator Cyclin D1. Moreover, we demonstrated the negative regulatory effect of TCPOBOP-activated CAR on the association of Foxo1 with the target Foxo1 itself and Cdkn1a(p21) promoters. Thus, we identified CAR-mediated repression of cell cycle inhibitor p21, as mediated by repression of FOXO1 expression and transcriptional activity. CAR-FOXO1 cross-talk may provide new opportunities for understanding liver diseases and developing more effective therapeutic approaches to better drug treatments

  18. Eukaryotic Cell Cycle as a Test Case for Modeling Cellular Regulation in a Collaborative Problem-Solving Environment

    Science.gov (United States)

    2007-03-01

    computer models of cell cycle regulation in a variety of organisms, including yeast cells, amphibian embryos, bacterial cells and human cells. These...and meiosis ), but they do not nullify the central role played by irreversible, alternating START and FINISH transitions in the cell cycle. 32...AFRL-IF-RS-TR-2007-69 Final Technical Report March 2007 EUKARYOTIC CELL CYCLE AS A TEST CASE FOR MODELING CELLULAR REGULATION IN A

  19. Rho/ROCK signaling in regulation of corneal epithelial cell cycle progression.

    Science.gov (United States)

    Chen, Jian; Guerriero, Emily; Lathrop, Kira; SundarRaj, Nirmala

    2008-01-01

    The authors' previous study showed that the expression of a Rho-associated serine/threonine kinase (ROCK) is regulated during cell cycle progression in corneal epithelial cells. The present study was conducted to determine whether and how Rho/ROCK signaling regulates cell cycle progression. Rabbit corneal epithelial cells (RCECs) in culture were arrested in the G(0) phase of the cell cycle by serum deprivation and then allowed to re-enter the cell cycle in the presence or absence of the ROCK inhibitor (Y27632) in serum-supplemented medium. The number of cells in the S phase, the relative levels of specific cyclins and CDKs and their intracellular distribution, and the relative levels of mRNAs were determined by BrdU labeling, Western blot and immunocytochemical analyses, and real-time RT-PCR, respectively. ROCK inhibition delayed the progression of G(1) to S phase and led to a decrease in the number of RCECs entering the S phase between 12 and 24 hours from 31.5% +/- 4.5% to 8.1% +/- 2.6%. During the cell cycle progression, protein and mRNA levels of cyclin-D1 and -D3 and cyclin-dependent kinases CDK4 and CDK6 were significantly lower, whereas the protein levels of the CDK inhibitor p27(Kip1) were higher in ROCK-inhibited cells. Intracellular mRNA or protein levels of cyclin-E and protein levels of CDK2 were not significantly affected, but their nuclear translocation was delayed by ROCK inhibition. ROCK signaling is involved in cell cycle progression in RCECs, possibly by upregulation of cyclin-D1 and -D3 and CDK4, -6, and -2; nuclear translocation of CDK2 and cyclin-E; and downregulation of p27(Kip1).

  20. CUDC-907 Promotes Bone Marrow Adipocytic Differentiation Through Inhibition of Histone Deacetylase and Regulation of Cell Cycle.

    Science.gov (United States)

    Ali, Dalia; Alshammari, Hassan; Vishnubalaji, Radhakrishnan; Chalisserry, Elna Paul; Hamam, Rimi; Alfayez, Musaad; Kassem, Moustapha; Aldahmash, Abdullah; Alajez, Nehad M

    2017-03-01

    The role of bone marrow adipocytes (BMAs) in overall energy metabolism and their effects on bone mass are currently areas of intensive investigation. BMAs differentiate from bone marrow stromal cells (BMSCs); however, the molecular mechanisms regulating BMA differentiation are not fully understood. In this study, we investigated the effect of CUDC-907, identified by screening an epigenetic small-molecule library, on adipocytic differentiation of human BMSCs (hBMSCs) and determined its molecular mechanism of action. Human bone marrow stromal cells exposed to CUDC-907 (500 nM) exhibited enhanced adipocytic differentiation (∼2.9-fold increase, P < 0.005) compared with that of control cells. Global gene expression and signaling pathway analyses of differentially expressed genes revealed a strong enrichment of genes involved in adipogenesis, cell cycle, and DNA replication. Chromatin immune precipitation combined with quantitative polymerase chain reaction showed significant increase in H3K9ac epigenetic marker in the promoter regions of AdipoQ, FABP4, PPARγ, KLF15, and CEBPA in CUDC-907-treated hBMSCs. Follow-up experiments corroborated that the inhibition of histone deacetylase (HDAC) activity enhanced adipocytic differentiation, while the inhibition of PI3K decreased adipocytic differentiation. In addition, CUDC-907 arrested hBMSCs in the G0-G1 phase of the cell cycle and reduced the number of S-phase cells. Our data reveal that HDAC, PI3K, and cell cycle genes are important regulators of BMA formation and demonstrate that adipocyte differentiation of hBMSCs is associated with complex changes in a number of epigenetic and genetic pathways, which can be targeted to regulate BMA formation.

  1. RGC-32 is a novel regulator of the T-lymphocyte cell cycle.

    Science.gov (United States)

    Tegla, Cosmin A; Cudrici, Cornelia D; Nguyen, Vinh; Danoff, Jacob; Kruszewski, Adam M; Boodhoo, Dallas; Mekala, Armugam P; Vlaicu, Sonia I; Chen, Ching; Rus, Violeta; Badea, Tudor C; Rus, Horea

    2015-06-01

    We have previously shown that RGC-32 is involved in cell cycle regulation in vitro. To define the in vivo role of RGC-32, we generated RGC-32 knockout mice. These mice developed normally and did not spontaneously develop overt tumors. To assess the effect of RGC-32 deficiency on cell cycle activation in T cells, we determined the proliferative rates of CD4(+) and CD8(+) T cells from the spleens of RGC-32(-/-) mice, as compared to wild-type (WT, RGC-32(+/+)) control mice. After stimulation with anti-CD3/anti-CD28, CD4(+) T cells from RGC-32(-/-) mice displayed a significant increase in [(3)H]-thymidine incorporation when compared to WT mice. In addition, both CD4(+) and CD8(+) T cells from RGC-32(-/-) mice displayed a significant increase in the proportion of proliferating Ki67(+) cells, indicating that in T cells, RGC-32 has an inhibitory effect on cell cycle activation induced by T-cell receptor/CD28 engagement. Furthermore, Akt and FOXO1 phosphorylation induced in stimulated CD4(+) T-cells from RGC-32(-/-) mice were significantly higher, indicating that RGC-32 inhibits cell cycle activation by suppressing FOXO1 activation. We also found that IL-2 mRNA and protein expression were significantly increased in RGC-32(-/-) CD4(+) T cells when compared to RGC-32(+/+) CD4(+) T cells. In addition, the effect of RGC-32 on the cell cycle and IL-2 expression was inhibited by pretreatment of the samples with LY294002, indicating a role for phosphatidylinositol 3-kinase (PI3K). Thus, RGC-32 is involved in controlling the cell cycle of T cells in vivo, and this effect is mediated by IL-2 in a PI3K-dependent fashion. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Cell cycle-dependent Rho GTPase activity dynamically regulates cancer cell motility and invasion in vivo.

    Science.gov (United States)

    Kagawa, Yoshinori; Matsumoto, Shinji; Kamioka, Yuji; Mimori, Koshi; Naito, Yoko; Ishii, Taeko; Okuzaki, Daisuke; Nishida, Naohiro; Maeda, Sakae; Naito, Atsushi; Kikuta, Junichi; Nishikawa, Keizo; Nishimura, Junichi; Haraguchi, Naotsugu; Takemasa, Ichiro; Mizushima, Tsunekazu; Ikeda, Masataka; Yamamoto, Hirofumi; Sekimoto, Mitsugu; Ishii, Hideshi; Doki, Yuichiro; Matsuda, Michiyuki; Kikuchi, Akira; Mori, Masaki; Ishii, Masaru

    2013-01-01

    The mechanism behind the spatiotemporal control of cancer cell dynamics and its possible association with cell proliferation has not been well established. By exploiting the intravital imaging technique, we found that cancer cell motility and invasive properties were closely associated with the cell cycle. In vivo inoculation of human colon cancer cells bearing fluorescence ubiquitination-based cell cycle indicator (Fucci) demonstrated an unexpected phenomenon: S/G2/M cells were more motile and invasive than G1 cells. Microarray analyses showed that Arhgap11a, an uncharacterized Rho GTPase-activating protein (RhoGAP), was expressed in a cell-cycle-dependent fashion. Expression of ARHGAP11A in cancer cells suppressed RhoA-dependent mechanisms, such as stress fiber formation and focal adhesion, which made the cells more prone to migrate. We also demonstrated that RhoA suppression by ARHGAP11A induced augmentation of relative Rac1 activity, leading to an increase in the invasive properties. RNAi-based inhibition of Arhgap11a reduced the invasion and in vivo expansion of cancers. Additionally, analysis of human specimens showed the significant up-regulation of Arhgap11a in colon cancers, which was correlated with clinical invasion status. The present study suggests that ARHGAP11A, a cell cycle-dependent RhoGAP, is a critical regulator of cancer cell mobility and is thus a promising therapeutic target in invasive cancers.

  3. Cell cycle-dependent Rho GTPase activity dynamically regulates cancer cell motility and invasion in vivo.

    Directory of Open Access Journals (Sweden)

    Yoshinori Kagawa

    Full Text Available The mechanism behind the spatiotemporal control of cancer cell dynamics and its possible association with cell proliferation has not been well established. By exploiting the intravital imaging technique, we found that cancer cell motility and invasive properties were closely associated with the cell cycle. In vivo inoculation of human colon cancer cells bearing fluorescence ubiquitination-based cell cycle indicator (Fucci demonstrated an unexpected phenomenon: S/G2/M cells were more motile and invasive than G1 cells. Microarray analyses showed that Arhgap11a, an uncharacterized Rho GTPase-activating protein (RhoGAP, was expressed in a cell-cycle-dependent fashion. Expression of ARHGAP11A in cancer cells suppressed RhoA-dependent mechanisms, such as stress fiber formation and focal adhesion, which made the cells more prone to migrate. We also demonstrated that RhoA suppression by ARHGAP11A induced augmentation of relative Rac1 activity, leading to an increase in the invasive properties. RNAi-based inhibition of Arhgap11a reduced the invasion and in vivo expansion of cancers. Additionally, analysis of human specimens showed the significant up-regulation of Arhgap11a in colon cancers, which was correlated with clinical invasion status. The present study suggests that ARHGAP11A, a cell cycle-dependent RhoGAP, is a critical regulator of cancer cell mobility and is thus a promising therapeutic target in invasive cancers.

  4. The human RNA polymerase II-associated factor 1 (hPaf1: a new regulator of cell-cycle progression.

    Directory of Open Access Journals (Sweden)

    Nicolas Moniaux

    2009-09-01

    Full Text Available The human PAF (hPAF complex is part of the RNA polymerase II transcription apparatus and regulates multiple steps in gene expression. Further, the yeast homolog of hPaf1 has a role in regulating the expression of a subset of genes involved in the cell-cycle. We therefore investigated the role of hPaf1 during progression of the cell-cycle.Herein, we report that the expression of hPaf1, a subunit of the hPAF complex, increases with cell-cycle progression and is regulated in a cell-cycle dependant manner. hPaf1 specifically regulates a subclass of genes directly implicated in cell-cycle progression during G1/S, S/G2, and G2/M. In prophase, hPaf1 aligns in filament-like structures, whereas in metaphase it is present within the pole forming a crown-like structure, surrounding the centrosomes. Moreover, hPaf1 is degraded during the metaphase to anaphase transition. In the nucleus, hPaf1 regulates the expression of cyclins A1, A2, D1, E1, B1, and Cdk1. In addition, expression of hPaf1 delays DNA replication but favors the G2/M transition, in part through microtubule assembly and mitotic spindle formation.Our results identify hPaf1 and the hPAF complex as key regulators of cell-cycle progression. Mutation or loss of stoichiometry of at least one of the members may potentially lead to cancer development.

  5. VRK1 regulates Cajal body dynamics and protects coilin from proteasomal degradation in cell cycle.

    Science.gov (United States)

    Cantarero, Lara; Sanz-García, Marta; Vinograd-Byk, Hadar; Renbaum, Paul; Levy-Lahad, Ephrat; Lazo, Pedro A

    2015-06-12

    Cajal bodies (CBs) are nuclear organelles associated with ribonucleoprotein functions and RNA maturation. CBs are assembled on coilin, its main scaffold protein, in a cell cycle dependent manner. The Ser-Thr VRK1 (vaccinia-related kinase 1) kinase, whose activity is also cell cycle regulated, interacts with and phosphorylates coilin regulating assembly of CBs. Coilin phosphorylation is not necessary for its interaction with VRK1, but it occurs in mitosis and regulates coilin stability. Knockdown of VRK1 or VRK1 inactivation by serum deprivation causes a loss of coilin phosphorylation in Ser184 and of CBs formation, which are rescued with an active VRK1, but not by kinase-dead VRK1. The phosphorylation of coilin in Ser184 occurs during mitosis before assembly of CBs. Loss of coilin phosphorylation results in disintegration of CBs, and of coilin degradation that is prevented by proteasome inhibitors. After depletion of VRK1, coilin is ubiquitinated in nuclei, which is partly mediated by mdm2, but its proteasomal degradation occurs in cytosol and is prevented by blocking its nuclear export. We conclude that VRK1 is a novel regulator of CBs dynamics and stability in cell cycle by protecting coilin from ubiquitination and degradation in the proteasome, and propose a model of CB dynamics.

  6. ABA Represses the Expression of Cell Cycle Genes and May Modulate the Development of Endodormancy in Grapevine Buds

    Directory of Open Access Journals (Sweden)

    Ricardo Vergara

    2017-05-01

    Full Text Available Recently, the plant hormone abscisic acid (ABA has been implicated as a key player in the regulation of endodormancy (ED in grapevine buds (Vitis vinifera L. In this study, we show that in the vine, the expression of genes related to the biosynthesis of ABA (VvNCED1; VvNCED2 and the content of ABA are significantly higher in the latent bud than at the shoot apex, while the expression of an ABA catabolic gene (VvA8H3 showed no significant difference between either organ. A negative correlation between the content of ABA and transcript levels of cell cycle genes (CCG was found in both tissues. This result suggested that ABA may negatively regulate the expression of CCG in meristematic tissues of grapevines. To test this proposition, the effect of ABA on the expression of CCG was analyzed in two meristematic tissues of the vine: somatic embryos and shoot apexes. The results indicated that cell cycle progression is repressed by ABA in both organs, since it down-regulated the expression of genes encoding cyclin-dependent kinases (VvCDKB1, VvCDKB2 and genes encoding cyclins of type A (VvCYCA1, VvCYCA2, VvCYCA3, B (VvCYCB, and D (VvCYCD3.2a and up-regulated the expression of VvICK5, a gene encoding an inhibitor of CDKs. During ED, the content of ABA increased, and the expression of CCG decreased. Moreover, the dormancy-breaking compound hydrogen cyanamide (HC reduced the content of ABA and up-regulated the expression of CCG, this last effect was abolished when HC and ABA were co-applied. Taken together, these results suggest that ABA-mediated repression of CCG transcription may be part of the mechanism through which ABA modulates the development of ED in grapevine buds.

  7. Cell-cycle regulation in green algae dividing by multiple fission

    Czech Academy of Sciences Publication Activity Database

    Bišová, Kateřina; Zachleder, Vilém

    2014-01-01

    Roč. 65, č. 10 (2014), s. 2585-2602 ISSN 0022-0957 R&D Projects: GA ČR M200201205; GA MŠk LH12145 Grant - others:Centre for Algal Biotechnologies (Algatech)(CZ) CZ.1.05/2.1.00/03.0110 Institutional support: RVO:61388971 Keywords : cell cycle * regulation * growth * light Subject RIV: EE - Microbiology, Virology Impact factor: 5.526, year: 2014

  8. Characterization of E2F8, a novel E2F-like cell-cycle regulated repressor of E2F-activated transcription

    DEFF Research Database (Denmark)

    Christensen, Jesper; Cloos, Paul; Toftegaard, Ulla

    2005-01-01

    The E2F family of transcription factors are downstream effectors of the retinoblastoma protein, pRB, pathway and are essential for the timely regulation of genes necessary for cell-cycle progression. Here we describe the characterization of human and murine E2F8, a new member of the E2F family...

  9. The cell cycle regulator ecdysoneless cooperates with H-Ras to promote oncogenic transformation of human mammary epithelial cells.

    Science.gov (United States)

    Bele, Aditya; Mirza, Sameer; Zhang, Ying; Ahmad Mir, Riyaz; Lin, Simon; Kim, Jun Hyun; Gurumurthy, Channabasavaiah Basavaraju; West, William; Qiu, Fang; Band, Hamid; Band, Vimla

    2015-01-01

    The mammalian ortholog of Drosophila ecdysoneless (Ecd) gene product regulates Rb-E2F interaction and is required for cell cycle progression. Ecd is overexpressed in breast cancer and its overexpression predicts shorter survival in patients with ErbB2-positive tumors. Here, we demonstrate Ecd knock down (KD) in human mammary epithelial cells (hMECs) induces growth arrest, similar to the impact of Ecd Knock out (KO) in mouse embryonic fibroblasts. Furthermore, whole-genome mRNA expression analysis of control vs. Ecd KD in hMECs demonstrated that several of the top 40 genes that were down-regulated were E2F target genes. To address the role of Ecd in mammary oncogenesis, we overexpressed Ecd and/or mutant H-Ras in hTERT-immortalized hMECs. Cell cycle analyses revealed hMECs overexpressing Ecd+Ras showed incomplete arrest in G1 phase upon growth factor deprivation, and more rapid cell cycle progression in growth factor-containing medium. Analyses of cell migration, invasion, acinar structures in 3-D Matrigel and anchorage-independent growth demonstrated that Ecd+Ras-overexpressing cells exhibit substantially more dramatic transformed phenotype as compared to cells expressing vector, Ras or Ecd. Under conditions of nutrient deprivation, Ecd+Ras-overexpressing hMECs exhibited better survival, with substantial upregulation of the autophagy marker LC3 both at the mRNA and protein levels. Significantly, while hMECs expressing Ecd or mutant Ras alone did not form tumors in NOD/SCID mice, Ecd+Ras-overexpressing hMECs formed tumors, clearly demonstrating oncogenic cooperation between Ecd and mutant Ras. Collectively, we demonstrate an important co-oncogenic role of Ecd in the progression of mammary oncogenesis through promoting cell survival.

  10. Znhit1 causes cell cycle arrest and down-regulates CDK6 expression

    International Nuclear Information System (INIS)

    Yang, Zhengmin; Cao, Yonghao; Zhu, Xiaoyan; Huang, Ying; Ding, Yuqiang; Liu, Xiaolong

    2009-01-01

    Cyclin-dependent kinase 6 (CDK6) is the key element of the D-type cyclin holoenzymes which has been found to function in the regulation of G1-phase of the cell cycle and is presumed to play important roles in T cell function. In this study, Znhit1, a member of a new zinc finger protein family defined by a conserved Zf-HIT domain, induced arrest in the G1-phase of the cell cycle in NIH/3T3 cells. Of the G1 cell cycle factors examined, the expression of CDK6 was found to be strongly down-regulated by Znhit1 via transcriptional repression. This effect may have correlations with the decreased acetylation level of histone H4 in the CDK6 promoter region. In addition, considering that CDK6 expression predominates in T cells, the negative regulatory role of Znhit1 in TCR-induced T cell proliferation was validated using transgenic mice. These findings identified Znhit1 as a CDK6 regulator that plays an important role in cell proliferation.

  11. Cell cycle regulation of the BRCA1/acetyl-CoA-carboxylase complex.

    Science.gov (United States)

    Ray, H; Suau, F; Vincent, A; Dalla Venezia, N

    2009-01-16

    Germ-line alterations in BRCA1 are associated with an increased susceptibility to breast and ovarian cancer. The BRCA1 protein has been implicated in multiple cellular functions. We have recently demonstrated that BRCA1 reduces acetyl-CoA-carboxylase alpha (ACCA) activity through its phospho-dependent binding to ACCA, and further established that the phosphorylation of the Ser1263 of ACCA is required for this interaction. Here, to gain more insight into the cellular conditions that trigger the BRCA1/ACCA interaction, we designed an anti-pSer1263 antibody and demonstrated that the Ser1263 of ACCA is phosphorylated in vivo, in a cell cycle-dependent manner. We further showed that the interaction between BRCA1 and ACCA is regulated during cell cycle progression. Taken together, our findings reveal a novel mechanism of regulation of ACCA distinct from the previously described phosphorylation of Ser79, and provide new insights into the control of lipogenesis through the cell cycle.

  12. Caulobacter crescentus Cell Cycle-Regulated DNA Methyltransferase Uses a Novel Mechanism for Substrate Recognition.

    Science.gov (United States)

    Woodcock, Clayton B; Yakubov, Aziz B; Reich, Norbert O

    2017-08-01

    Caulobacter crescentus relies on DNA methylation by the cell cycle-regulated methyltransferase (CcrM) in addition to key transcription factors to control the cell cycle and direct cellular differentiation. CcrM is shown here to efficiently methylate its cognate recognition site 5'-GANTC-3' in single-stranded and hemimethylated double-stranded DNA. We report the K m , k cat , k methylation , and K d for single-stranded and hemimethylated substrates, revealing discrimination of 10 7 -fold for noncognate sequences. The enzyme also shows a similar discrimination against single-stranded RNA. Two independent assays clearly show that CcrM is highly processive with single-stranded and hemimethylated DNA. Collectively, the data provide evidence that CcrM and other DNA-modifying enzymes may use a new mechanism to recognize DNA in a key epigenetic process.

  13. A balance of FGF and BMP signals regulates cell cycle exit and Equarin expression in lens cells

    Science.gov (United States)

    Jarrin, Miguel; Pandit, Tanushree; Gunhaga, Lena

    2012-01-01

    In embryonic and adult lenses, a balance of cell proliferation, cell cycle exit, and differentiation is necessary to maintain physical function. The molecular mechanisms regulating the transition of proliferating lens epithelial cells to differentiated primary lens fiber cells are poorly characterized. To investigate this question, we used gain- and loss-of-function analyses to modulate fibroblast growth factor (FGF) and/or bone morphogenetic protein (BMP) signals in chick lens/retina explants. Here we show that FGF activity plays a key role for proliferation independent of BMP signals. Moreover, a balance of FGF and BMP signals regulates cell cycle exit and the expression of Ccdc80 (also called Equarin), which is expressed at sites where differentiation of lens fiber cells occurs. BMP activity promotes cell cycle exit and induces Equarin expression in an FGF-dependent manner. In contrast, FGF activity is required but not sufficient to induce cell cycle exit or Equarin expression. Furthermore, our results show that in the absence of BMP activity, lens cells have increased cell cycle length or are arrested in the cell cycle, which leads to decreased cell cycle exit. Taken together, these findings suggest that proliferation, cell cycle exit, and early differentiation of primary lens fiber cells are regulated by counterbalancing BMP and FGF signals. PMID:22718906

  14. Cell cycle regulation of DNA polymerase beta in rotenone-based Parkinson's disease models.

    Directory of Open Access Journals (Sweden)

    Hongcai Wang

    Full Text Available In Parkinson's disease (PD, neuronal cells undergo mitotic catastrophe and endoreduplication prior to cell death; however, the regulatory mechanisms remain to be defined. In this study, we investigated cell cycle regulation of DNA polymerase β (poly β in rotenone-based dopaminergic cellular and animal models. Incubation with a low concentration (0.25 µM of rotenone for 1.5 to 7 days resulted in a flattened cell body and decreased DNA replication during S phase, whereas a high concentration (2 µM of rotenone exposure resulted in enlarged, multi-nucleated cells and converted the mitotic cycle into endoreduplication. Consistently, DNA poly β, which is mainly involved in DNA repair synthesis, was upregulated to a high level following exposure to 2 µM rotenone. The abrogation of DNA poly β by siRNA transfection or dideoxycytidine (DDC treatment attenuated the rotenone-induced endoreduplication. The cell cycle was reactivated in cyclin D-expressing dopaminergic neurons from the substantia nigra (SN of rats following stereotactic (ST infusion of rotenone. Increased DNA poly β expression was observed in the substantia nigra pars compacta (SNc and the substantia nigra pars reticulate (SNr of rotenone-treated rats. Collectively, in the in vitro model of rotenone-induced mitotic catastrophe, the overexpression of DNA poly β promotes endoreduplication; in the in vivo model, the upregulation of DNA poly β and cell cycle reentry were also observed in the adult rat substantia nigra. Therefore, the cell cycle regulation of DNA poly β may be involved in the pathological processes of PD, which results in the induction of endoreduplication.

  15. Cell cycle regulation by feed-forward loops coupling transcription and phosphorylation

    DEFF Research Database (Denmark)

    Csikász-Nagy, Attila; Kapuy, Orsolya; Tóth, Attila

    2009-01-01

    of these EPs. From genome-scale data sets of budding yeast, we identify 126 EPs that are regulated by Cdk1 both through direct phosphorylation of the EP and through phosphorylation of the transcription factors that control expression of the EP, so that each of these EPs is regulated by a feed-forward loop (FFL......) from Cdk1. By mathematical modelling, we show that such FFLs can activate EPs at different phases of the cell cycle depending of the effective signs (+ or -) of the regulatory steps of the FFL. We provide several case studies of EPs that are controlled by FFLs exactly as our models predict. The signal...

  16. Functional analysis of the cell cycle regulator Rca1 in Drosophila melanogaster

    OpenAIRE

    Zielke, Norman

    2007-01-01

    Tight regulation of APC/C activity is essential for cell cycle progression. An important class of negative APC/C regulators are the Rca1/Emi1 family proteins. All members of the Rca1/Emi1 family share a conserved zinc binding region (ZBR) which is essential for their inhibitory activity. The Rca1/Emi1 proteins belong to the class of F-box proteins that are known to act as substrate recognition subunits in SCF-E3-ligase complexes. Emi1 and Rca1 interact in vitro with members of the Skp family ...

  17. Situational Awareness: Regulation of the Myb Transcription Factor in Differentiation, the Cell Cycle and Oncogenesis

    Energy Technology Data Exchange (ETDEWEB)

    George, Olivia L.; Ness, Scott A., E-mail: sness@salud.unm.edu [Department of Internal Medicine, Section of Molecular Medicine, University of New Mexico Health Sciences Center, MSC07 4025-CRF 121, 1 University of New Mexico, Albuquerque, NM 87131 (United States)

    2014-10-02

    This review summarizes the mechanisms that control the activity of the c-Myb transcription factor in normal cells and tumors, and discusses how c-Myb plays a role in the regulation of the cell cycle. Oncogenic versions of c-Myb contribute to the development of leukemias and solid tumors such as adenoid cystic carcinoma, breast cancer and colon cancer. The activity and specificity of the c-Myb protein seems to be controlled through changes in protein-protein interactions, so understanding how it is regulated could lead to the development of novel therapeutic strategies.

  18. Cell cycle-related genes as modifiers of age of onset of colorectal cancer in Lynch syndrome: a large-scale study in non-Hispanic white patients.

    Science.gov (United States)

    Chen, Jinyun; Pande, Mala; Huang, Yu-Jing; Wei, Chongjuan; Amos, Christopher I; Talseth-Palmer, Bente A; Meldrum, Cliff J; Chen, Wei V; Gorlov, Ivan P; Lynch, Patrick M; Scott, Rodney J; Frazier, Marsha L

    2013-02-01

    Heterogeneity in age of onset of colorectal cancer in individuals with mutations in DNA mismatch repair genes (Lynch syndrome) suggests the influence of other lifestyle and genetic modifiers. We hypothesized that genes regulating the cell cycle influence the observed heterogeneity as cell cycle-related genes respond to DNA damage by arresting the cell cycle to provide time for repair and induce transcription of genes that facilitate repair. We examined the association of 1456 single nucleotide polymorphisms (SNPs) in 128 cell cycle-related genes and 31 DNA repair-related genes in 485 non-Hispanic white participants with Lynch syndrome to determine whether there are SNPs associated with age of onset of colorectal cancer. Genotyping was performed on an Illumina GoldenGate platform, and data were analyzed using Kaplan-Meier survival analysis, Cox regression analysis and classification and regression tree (CART) methods. Ten SNPs were independently significant in a multivariable Cox proportional hazards regression model after correcting for multiple comparisons (P Lynch syndrome.

  19. UV-induced changes in cell cycle and gene expression within rabbit lens epithelial cells

    International Nuclear Information System (INIS)

    Sidjanin, D.; Grdina, D.; Woloschak, G.E.

    1996-01-01

    Damage to lens epithelial cells is a probable initiation process in cataract formation mediated by UV radiation. In these experiments, we investigated the effects of exposure to 254 nm radiation on cell cycle progression in the rabbit lens epithelial cell line N/N1003A. The RNA was harvested at various times following exposure to UV (254 nm) radiation and analyzed by dot-blot and northern blot hybridizations. These results revealed that during the first 6 h following exposure of the cells to UV, there was, associated with decreasing dose, a decrease in accumulation of transcripts specific for histones H3 and H4 and an increase in the mRNA encoding protein kinase C and β- and γ-actin. Using flow cytometry, we detected an accumulation of cells in G1/S phase of the cell cycle 1 h following exposure to 254 nm radiation. The observed changes in gene expression, especially the decreased accumulation of histone transcripts reported here, may play a role in UV-induced inhibition of cell cycle progression. (Author)

  20. A data-driven, mathematical model of mammalian cell cycle regulation.

    Directory of Open Access Journals (Sweden)

    Michael C Weis

    Full Text Available Few of >150 published cell cycle modeling efforts use significant levels of data for tuning and validation. This reflects the difficultly to generate correlated quantitative data, and it points out a critical uncertainty in modeling efforts. To develop a data-driven model of cell cycle regulation, we used contiguous, dynamic measurements over two time scales (minutes and hours calculated from static multiparametric cytometry data. The approach provided expression profiles of cyclin A2, cyclin B1, and phospho-S10-histone H3. The model was built by integrating and modifying two previously published models such that the model outputs for cyclins A and B fit cyclin expression measurements and the activation of B cyclin/Cdk1 coincided with phosphorylation of histone H3. The model depends on Cdh1-regulated cyclin degradation during G1, regulation of B cyclin/Cdk1 activity by cyclin A/Cdk via Wee1, and transcriptional control of the mitotic cyclins that reflects some of the current literature. We introduced autocatalytic transcription of E2F, E2F regulated transcription of cyclin B, Cdc20/Cdh1 mediated E2F degradation, enhanced transcription of mitotic cyclins during late S/early G2 phase, and the sustained synthesis of cyclin B during mitosis. These features produced a model with good correlation between state variable output and real measurements. Since the method of data generation is extensible, this model can be continually modified based on new correlated, quantitative data.

  1. TEAD4-YAP interaction regulates tumoral growth by controlling cell-cycle arrest at the G1 phase

    International Nuclear Information System (INIS)

    Takeuchi, Shin; Kasamatsu, Atsushi; Yamatoji, Masanobu; Nakashima, Dai; Endo-Sakamoto, Yosuke; Koide, Nao; Takahara, Toshikazu; Shimizu, Toshihiro; Iyoda, Manabu; Ogawara, Katsunori; Shiiba, Masashi; Tanzawa, Hideki; Uzawa, Katsuhiro

    2017-01-01

    TEA domain transcription factor 4 (TEAD4), which has critical functions in the process of embryonic development, is expressed in various cancers. However, the important role of TEAD4 in human oral squamous cell carcinomas (OSCCs) remain unclear. Here we investigated the TEAD4 expression level and the functional mechanism in OSCC using quantitative reverse transcriptase-polymerase chain reaction, Western blot analysis, and immunohistochemistry. Furthermore, TEAD4 knockdown model was used to evaluate cellular proliferation, cell-cycle analysis, and the interaction between TEAD4 and Yes-associated protein (YAP) which was reported to be a transcription coactivator of cellular proliferation. In the current study, we found that TEAD4 expression increased significantly in vitro and in vivo and correlated with tumoral size in OSCC patients. TEAD4 knockdown OSCC cells showed decreased cellular proliferation resulting from cell-cycle arrest in the G1 phase by down-regulation of cyclins, cyclin-dependent kinases (CDKs), and up-regulation of CDK inhibitors. We also found that the TEAD4-YAP complex in the nuclei may be related closely to transcriptions of G1 arrest-related genes. Taken together, we concluded that TEAD4 might play an important role in tumoral growth and have potential to be a therapeutic target in OSCCs. - Highlights: • TEAD4 contributes to tumor progression in OSCCs. • TEAD4 knockdown results in cell-cycle arrest at the G1phase in OSCC cells. • In TEAD4 knockdown cells, the amount of YAP in the nucleus decreases. • Activation of the TEAD4-YAP complex is an important factor in OSCC tumor growth. • TEAD4 might be a critical biomarker and a therapeutic target for OSCCs.

  2. Simulated microgravity, Mars gravity, and 2g hypergravity affect cell cycle regulation, ribosome biogenesis, and epigenetics in Arabidopsis cell cultures.

    Science.gov (United States)

    Kamal, Khaled Y; Herranz, Raúl; van Loon, Jack J W A; Medina, F Javier

    2018-04-23

    Gravity is the only component of Earth environment that remained constant throughout the entire process of biological evolution. However, it is still unclear how gravity affects plant growth and development. In this study, an in vitro cell culture of Arabidopsis thaliana was exposed to different altered gravity conditions, namely simulated reduced gravity (simulated microgravity, simulated Mars gravity) and hypergravity (2g), to study changes in cell proliferation, cell growth, and epigenetics. The effects after 3, 14, and 24-hours of exposure were evaluated. The most relevant alterations were found in the 24-hour treatment, being more significant for simulated reduced gravity than hypergravity. Cell proliferation and growth were uncoupled under simulated reduced gravity, similarly, as found in meristematic cells from seedlings grown in real or simulated microgravity. The distribution of cell cycle phases was changed, as well as the levels and gene transcription of the tested cell cycle regulators. Ribosome biogenesis was decreased, according to levels and gene transcription of nucleolar proteins and the number of inactive nucleoli. Furthermore, we found alterations in the epigenetic modifications of chromatin. These results show that altered gravity effects include a serious disturbance of cell proliferation and growth, which are cellular functions essential for normal plant development.

  3. Systematic identification of yeast cell cycle transcription factors using multiple data sources

    Directory of Open Access Journals (Sweden)

    Li Wen-Hsiung

    2008-12-01

    Full Text Available Abstract Background Eukaryotic cell cycle is a complex process and is precisely regulated at many levels. Many genes specific to the cell cycle are regulated transcriptionally and are expressed just before they are needed. To understand the cell cycle process, it is important to identify the cell cycle transcription factors (TFs that regulate the expression of cell cycle-regulated genes. Results We developed a method to identify cell cycle TFs in yeast by integrating current ChIP-chip, mutant, transcription factor binding site (TFBS, and cell cycle gene expression data. We identified 17 cell cycle TFs, 12 of which are known cell cycle TFs, while the remaining five (Ash1, Rlm1, Ste12, Stp1, Tec1 are putative novel cell cycle TFs. For each cell cycle TF, we assigned specific cell cycle phases in which the TF functions and identified the time lag for the TF to exert regulatory effects on its target genes. We also identified 178 novel cell cycle-regulated genes, among which 59 have unknown functions, but they may now be annotated as cell cycle-regulated genes. Most of our predictions are supported by previous experimental or computational studies. Furthermore, a high confidence TF-gene regulatory matrix is derived as a byproduct of our method. Each TF-gene regulatory relationship in this matrix is supported by at least three data sources: gene expression, TFBS, and ChIP-chip or/and mutant data. We show that our method performs better than four existing methods for identifying yeast cell cycle TFs. Finally, an application of our method to different cell cycle gene expression datasets suggests that our method is robust. Conclusion Our method is effective for identifying yeast cell cycle TFs and cell cycle-regulated genes. Many of our predictions are validated by the literature. Our study shows that integrating multiple data sources is a powerful approach to studying complex biological systems.

  4. Tumor suppressor BLU inhibits proliferation of nasopharyngeal carcinoma cells by regulation of cell cycle, c-Jun N-terminal kinase and the cyclin D1 promoter

    International Nuclear Information System (INIS)

    Zhang, Xiangning; Liu, Hui; Li, Binbin; Huang, Peichun; Shao, Jianyong; He, Zhiwei

    2012-01-01

    Tumor suppressor genes function to regulate and block tumor cell proliferation. To explore the mechanisms underlying the tumor suppression of BLU/ZMYND10 gene on a frequently lost human chromosomal region, an adenoviral vector with BLU cDNA insert was constructed. BLU was re-expressed in nasopharyngeal carcinoma cells by transfection or viral infection. Clonogenic growth was assayed; cell cycle was analyzed by flow cytometry-based DNA content detection; c-Jun N-terminal kinase (JNK) and cyclin D1 promoter activities were measured by reporter gene assay, and phosphorylation was measured by immunoblotting. The data for each pair of groups were compared with Student t tests. BLU inhibits clonogenic growth of nasopharyngeal carcinoma cells, arrests cell cycle at G1 phase, downregulates JNK and cyclin D1 promoter activities, and inhibits phosphorylation of c-Jun. BLU inhibits growth of nasopharyngeal carcinoma cells by regulation of the JNK-cyclin D1 axis to exert tumor suppression

  5. E2F1-mediated upregulation of p19INK4d determines its periodic expression during cell cycle and regulates cellular proliferation.

    Science.gov (United States)

    Carcagno, Abel L; Marazita, Mariela C; Ogara, María F; Ceruti, Julieta M; Sonzogni, Silvina V; Scassa, María E; Giono, Luciana E; Cánepa, Eduardo T

    2011-01-01

    A central aspect of development and disease is the control of cell proliferation through regulation of the mitotic cycle. Cell cycle progression and directionality requires an appropriate balance of positive and negative regulators whose expression must fluctuate in a coordinated manner. p19INK4d, a member of the INK4 family of CDK inhibitors, has a unique feature that distinguishes it from the remaining INK4 and makes it a likely candidate for contributing to the directionality of the cell cycle. p19INK4d mRNA and protein levels accumulate periodically during the cell cycle under normal conditions, a feature reminiscent of cyclins. In this paper, we demonstrate that p19INK4d is transcriptionally regulated by E2F1 through two response elements present in the p19INK4d promoter. Ablation of this regulation reduced p19 levels and restricted its expression during the cell cycle, reflecting the contribution of a transcriptional effect of E2F1 on p19 periodicity. The induction of p19INK4d is delayed during the cell cycle compared to that of cyclin E, temporally separating the induction of these proliferative and antiproliferative target genes. Specific inhibition of the E2F1-p19INK4d pathway using triplex-forming oligonucleotides that block E2F1 binding on p19 promoter, stimulated cell proliferation and increased the fraction of cells in S phase. The results described here support a model of normal cell cycle progression in which, following phosphorylation of pRb, free E2F induces cyclin E, among other target genes. Once cyclinE/CDK2 takes over as the cell cycle driving kinase activity, the induction of p19 mediated by E2F1 leads to inhibition of the CDK4,6-containing complexes, bringing the G1 phase to an end. This regulatory mechanism constitutes a new negative feedback loop that terminates the G1 phase proliferative signal, contributing to the proper coordination of the cell cycle and provides an additional mechanism to limit E2F activity.

  6. E2F1-mediated upregulation of p19INK4d determines its periodic expression during cell cycle and regulates cellular proliferation.

    Directory of Open Access Journals (Sweden)

    Abel L Carcagno

    Full Text Available BACKGROUND: A central aspect of development and disease is the control of cell proliferation through regulation of the mitotic cycle. Cell cycle progression and directionality requires an appropriate balance of positive and negative regulators whose expression must fluctuate in a coordinated manner. p19INK4d, a member of the INK4 family of CDK inhibitors, has a unique feature that distinguishes it from the remaining INK4 and makes it a likely candidate for contributing to the directionality of the cell cycle. p19INK4d mRNA and protein levels accumulate periodically during the cell cycle under normal conditions, a feature reminiscent of cyclins. METHODOLOGY/PRINCIPAL FINDINGS: In this paper, we demonstrate that p19INK4d is transcriptionally regulated by E2F1 through two response elements present in the p19INK4d promoter. Ablation of this regulation reduced p19 levels and restricted its expression during the cell cycle, reflecting the contribution of a transcriptional effect of E2F1 on p19 periodicity. The induction of p19INK4d is delayed during the cell cycle compared to that of cyclin E, temporally separating the induction of these proliferative and antiproliferative target genes. Specific inhibition of the E2F1-p19INK4d pathway using triplex-forming oligonucleotides that block E2F1 binding on p19 promoter, stimulated cell proliferation and increased the fraction of cells in S phase. CONCLUSIONS/SIGNIFICANCE: The results described here support a model of normal cell cycle progression in which, following phosphorylation of pRb, free E2F induces cyclin E, among other target genes. Once cyclinE/CDK2 takes over as the cell cycle driving kinase activity, the induction of p19 mediated by E2F1 leads to inhibition of the CDK4,6-containing complexes, bringing the G1 phase to an end. This regulatory mechanism constitutes a new negative feedback loop that terminates the G1 phase proliferative signal, contributing to the proper coordination of the cell

  7. The cell cycle regulator CCDC6 is a key target of RNA-binding protein EWS.

    Directory of Open Access Journals (Sweden)

    Sujitha Duggimpudi

    Full Text Available Genetic translocation of EWSR1 to ETS transcription factor coding region is considered as primary cause for Ewing sarcoma. Previous studies focused on the biology of chimeric transcription factors formed due to this translocation. However, the physiological consequences of heterozygous EWSR1 loss in these tumors have largely remained elusive. Previously, we have identified various mRNAs bound to EWS using PAR-CLIP. In this study, we demonstrate CCDC6, a known cell cycle regulator protein, as a novel target regulated by EWS. siRNA mediated down regulation of EWS caused an elevated apoptosis in cells in a CCDC6-dependant manner. This effect was rescued upon re-expression of CCDC6. This study provides evidence for a novel functional link through which wild-type EWS operates in a target-dependant manner in Ewing sarcoma.

  8. Regulation of cAMP on the first mitotic cell cycle of mouse embryos.

    Science.gov (United States)

    Yu, Aiming; Zhang, Zhe; Bi, Qiang; Sun, Bingqi; Su, Wenhui; Guan, Yifu; Mu, Runqing; Miao, Changsheng; Zhang, Jie; Yu, Bingzhi

    2008-03-01

    Mitosis promoting factor (MPF) plays a central role during the first mitosis of mouse embryo. We demonstrated that MPF activity increased when one-cell stage mouse embryo initiated G2/M transition following the decrease of cyclic adenosine 3', 5'-monophosphate (cAMP) and cAMP-dependent protein kinase (PKA) activity. When cAMP and PKA activity increases again, MPF activity decreases and mouse embryo starts metaphase-anaphase transition. In the downstream of cAMP/PKA, there are some effectors such as polo-like kinase 1 (Plk1), Cdc25, Mos (mitogen-activated protein kinase kinase kinase), MEK (mitogen-activated protein kinase kinase), mitogen-activated protein kinase (MAPK), Wee1, anaphase-promoting complex (APC), and phosphoprotein phosphatase that are involved in the regulation of MPF activity. Here, we demonstrated that following activation of MPF, MAPK activity was steady, whereas Plk1 activity fluctuated during the first cell cycle. Plk1 activity was the highest at metaphase and decreased at metaphase-anaphase transition. Further, we established a mathematical model using Gepasi algorithm and the simulation was in agreement with the experimental data. Above all the evidences, we suggested that cAMP and PKA might be the upstream factors which were included in the regulation of the first cell cycle development of mouse embryo. Copyright 2007 Wiley-Liss, Inc.

  9. Stable Regulation of Cell Cycle Events in Mycobacteria: Insights From Inherently Heterogeneous Bacterial Populations.

    Science.gov (United States)

    Logsdon, Michelle M; Aldridge, Bree B

    2018-01-01

    Model bacteria, such as E. coli and B. subtilis , tightly regulate cell cycle progression to achieve consistent cell size distributions and replication dynamics. Many of the hallmark features of these model bacteria, including lateral cell wall elongation and symmetric growth and division, do not occur in mycobacteria. Instead, mycobacterial growth is characterized by asymmetric polar growth and division. This innate asymmetry creates unequal birth sizes and growth rates for daughter cells with each division, generating a phenotypically heterogeneous population. Although the asymmetric growth patterns of mycobacteria lead to a larger variation in birth size than typically seen in model bacterial populations, the cell size distribution is stable over time. Here, we review the cellular mechanisms of growth, division, and cell cycle progression in mycobacteria in the face of asymmetry and inherent heterogeneity. These processes coalesce to control cell size. Although Mycobacterium smegmatis and Mycobacterium bovis Bacillus Calmette-Guérin (BCG) utilize a novel model of cell size control, they are similar to previously studied bacteria in that initiation of DNA replication is a key checkpoint for cell division. We compare the regulation of DNA replication initiation and strategies used for cell size homeostasis in mycobacteria and model bacteria. Finally, we review the importance of cellular organization and chromosome segregation relating to the physiology of mycobacteria and consider how new frameworks could be applied across the wide spectrum of bacterial diversity.

  10. Stable Regulation of Cell Cycle Events in Mycobacteria: Insights From Inherently Heterogeneous Bacterial Populations

    Directory of Open Access Journals (Sweden)

    Michelle M. Logsdon

    2018-03-01

    Full Text Available Model bacteria, such as E. coli and B. subtilis, tightly regulate cell cycle progression to achieve consistent cell size distributions and replication dynamics. Many of the hallmark features of these model bacteria, including lateral cell wall elongation and symmetric growth and division, do not occur in mycobacteria. Instead, mycobacterial growth is characterized by asymmetric polar growth and division. This innate asymmetry creates unequal birth sizes and growth rates for daughter cells with each division, generating a phenotypically heterogeneous population. Although the asymmetric growth patterns of mycobacteria lead to a larger variation in birth size than typically seen in model bacterial populations, the cell size distribution is stable over time. Here, we review the cellular mechanisms of growth, division, and cell cycle progression in mycobacteria in the face of asymmetry and inherent heterogeneity. These processes coalesce to control cell size. Although Mycobacterium smegmatis and Mycobacterium bovis Bacillus Calmette-Guérin (BCG utilize a novel model of cell size control, they are similar to previously studied bacteria in that initiation of DNA replication is a key checkpoint for cell division. We compare the regulation of DNA replication initiation and strategies used for cell size homeostasis in mycobacteria and model bacteria. Finally, we review the importance of cellular organization and chromosome segregation relating to the physiology of mycobacteria and consider how new frameworks could be applied across the wide spectrum of bacterial diversity.

  11. Study of the G2/M cell cycle checkpoint in irradiated mammary epithelial cells overexpressing Cul-4A gene

    International Nuclear Information System (INIS)

    Gupta, Anu; Yang, L.-X.; Chen, L.-C.

    2002-01-01

    Purpose: Members of the cullin gene family are known to be involved in cell cycle control. One of the cullin genes, Cul-4A, is amplified and overexpressed in breast cancer cells. This study investigates the effect of Cul-4A overexpression upon G2/M cell cycle checkpoint after DNA damage induced by either ionizing or nonionizing radiation. Methods and Materials: The normal mammary epithelial cell line MCF10A was stably transfected with full-length Cul-4A cDNA. Independent clones of MCF10A cells that overexpress Cul-4A proteins were selected and treated with either 8 Gy of ionizing radiation or 7 J/M 2 of UV radiation. The profile of cell cycle progression and the accumulation of several cell cycle proteins were analyzed. Results: We found that overexpression of Cul-4A in MCF10A cells abrogated the G2/M cell cycle checkpoint in response to DNA damage induced by ionizing irradiation, but not to DNA damage induced by nonionizing radiation. Analysis of cell cycle proteins showed that after ionizing irradiation, p53 accumulated in the mock-transfected MCF10A cells, but not in the Cul-4A transfectants. Conclusion: Our results suggest a role for Cul-4A in tumorigenesis and/or tumor progression, possibly through disruption of cell cycle control

  12. Transcriptional Waves in the Yeast Cell Cycle

    OpenAIRE

    Oliva, Anna; Rosebrock, Adam; Ferrezuelo, Francisco; Pyne, Saumyadipta; Chen, Haiying; Skiena, Steve; Futcher, Bruce; Leatherwood, Janet

    2005-01-01

    Many genes are regulated as an innate part of the eukaryotic cell cycle, and a complex transcriptional network helps enable the cyclic behavior of dividing cells. This transcriptional network has been studied in Saccharomyces cerevisiae (budding yeast) and elsewhere. To provide more perspective on these regulatory mechanisms, we have used microarrays to measure gene expression through the cell cycle of Schizosaccharomyces pombe (fission yeast). The 750 genes with the most significant oscillat...

  13. Analysis of cell-cycle regulation following exposure of lung-derived cells to γ-rays

    Science.gov (United States)

    Trani, D.; Lucchetti, C.; Cassone, M.; D'Agostino, L.; Caputi, M.; Giordano, A.

    Acute exposure of mammalian cells to ionizing radiation results in a delay of cell-cycle progression and/or augmentation of apoptosis. Following ionizing radiation-induced DNA damage, cell-cycle arrest in the G1- or G2-phase of the cell-cycle prevents or delays DNA replication or mitosis, providing time for the DNA repair machinery to exert its function. Deregulation or failing of cell-cycle checkpoints and/or DNA repair mechanisms may lead normal cells bearing chromosome mutations to acquire neoplastic autonomy, which in turn can trigger the onset of cancer. Existing studies have focused on the impact of p53 status on the radiation response of lung cancer (LC) cell lines in terms of both cell-cycle regulation and apoptosis, while no comparative studies have been performed on the radiation response of lung derived normal and cancerous epithelial cells. To investigate the radiation response in normal and cancerous phenotypes, along with the role and impact of p53 status, and possible correlations with pRb/p105 or other proteins involved in carcinogenesis and cell-cycle regulation, we selected two lung-derived epithelial cell lines, one normal (NL20, p53 wild-type) and one non-small cell lung cancer (NSCLC), H358 (known to be p53-deficient). We compared the levels of γ-induced cell proliferation ability, cell-cycle arrest, apoptotic index, and expression levels of cell-cycle regulating and regulated proteins. The different cell sensitivity, apoptotic response and protein expression profiles resulting from our study for NL20 and H358 cells suggest that still unknown mechanisms involving p53, pRb/p105 and their target molecules might play a pivotal role in determining cell sensitivity and resistance upon exposure to ionizing radiation.

  14. Effectiveness and student perceptions of an active learning activity using a headline news story to enhance in-class learning of cell cycle regulation.

    Science.gov (United States)

    Dirks-Naylor, Amie J

    2016-06-01

    An active learning activity was used to engage students and enhance in-class learning of cell cycle regulation in a PharmD level integrated biological sciences course. The aim of the present study was to determine the effectiveness and perception of the in-class activity. After completion of a lecture on the topic of cell cycle regulation, students completed a 10-question multiple-choice quiz before and after engaging in the activity. The activity involved reading of a headline news article published by ScienceDaily.com entitled "One Gene Lost Equals One limb Regained." The name of the gene was deleted from the article and, thus, the end goal of the activity was to determine the gene of interest by the description in the story. The activity included compiling a list of all potential gene candidates before sufficient information was given to identify the gene of interest (p21). A survey was completed to determine student perceptions of the activity. Quiz scores improved by an average of 20% after the activity (40.1 ± 1.95 vs. 59.9 ± 2.14,Pactivity, found the news article interesting, and believed that the activity improved their understanding of cell cycle regulation. The majority of students agreed that the in-class activity piqued their interest for learning the subject matter and also agreed that if they understand a concept during class, they are more likely to want to study that concept outside of class. In conclusion, the activity improved in-class understanding and enhanced interest in cell cycle regulation. Copyright © 2016 The American Physiological Society.

  15. Centriole maturation requires regulated Plk1 activity during two consecutive cell cycles.

    Science.gov (United States)

    Kong, Dong; Farmer, Veronica; Shukla, Anil; James, Jana; Gruskin, Richard; Kiriyama, Shigeo; Loncarek, Jadranka

    2014-09-29

    Newly formed centrioles in cycling cells undergo a maturation process that is almost two cell cycles long before they become competent to function as microtubule-organizing centers and basal bodies. As a result, each cell contains three generations of centrioles, only one of which is able to form cilia. It is not known how this long and complex process is regulated. We show that controlled Plk1 activity is required for gradual biochemical and structural maturation of the centrioles and timely appendage assembly. Inhibition of Plk1 impeded accumulation of appendage proteins and appendage formation. Unscheduled Plk1 activity, either in cycling or interphase-arrested cells, accelerated centriole maturation and appendage and cilia formation on the nascent centrioles, erasing the age difference between centrioles in one cell. These findings provide a new understanding of how the centriole cycle is regulated and how proper cilia and centrosome numbers are maintained in the cells.

  16. Responses of genes involved in cell cycle control to diverse DNA damaging chemicals in human lung adenocarcinoma A549 cells

    Directory of Open Access Journals (Sweden)

    Gooderham Nigel J

    2005-08-01

    Full Text Available Abstract Background Many anticancer agents and carcinogens are DNA damaging chemicals and exposure to such chemicals results in the deregulation of cell cycle progression. The molecular mechanisms of DNA damage-induced cell cycle alteration are not well understood. We have studied the effects of etoposide (an anticancer agent, cryptolepine (CLP, a cytotoxic alkaloid, benzo [a]pyrene (BaP, a carcinogenic polycyclic aromatic hydrocarbon and 2-amino-1-methyl-6-phenylimidazo [4,5-b]pyridine (PhIP, a cooked-meat derived carcinogen on the expression of cell cycle regulatory genes to understand the molecular mechanisms of the cell cycle disturbance. Results A549 cells were treated with DMSO or chemicals for up to 72 h and periodically sampled for cell cycle analysis, mRNA and protein expression. DMSO treated cells showed a dominant G1 peak in cell cycle at all times examined. Etoposide and CLP both induced G2/M phase arrest yet the former altered the expression of genes functioning at multiple phases, whilst the latter was more effective in inhibiting the expression of genes in G2-M transition. Both etoposide and CLP induced an accumulation of p53 protein and upregulation of p53 transcriptional target genes. Neither BaP nor PhIP had substantial phase-specific cell cycle effect, however, they induced distinctive changes in gene expression. BaP upregulated the expression of CYP1B1 at 6–24 h and downregulated many cell cycle regulatory genes at 48–72 h. By contrast, PhIP increased the expression of many cell cycle regulatory genes. Changes in the expression of key mRNAs were confirmed at protein level. Conclusion Our experiments show that DNA damaging agents with different mechanisms of action induced distinctive changes in the expression pattern of a panel of cell cycle regulatory genes. We suggest that examining the genomic response to chemical exposure provides an exceptional opportunity to understand the molecular mechanism involved in cellular

  17. Innervating sympathetic neurons regulate heart size and the timing of cardiomyocyte cell cycle withdrawal.

    Science.gov (United States)

    Kreipke, R E; Birren, S J

    2015-12-01

    Sympathetic drive to the heart is a key modulator of cardiac function and interactions between heart tissue and innervating sympathetic fibres are established early in development. Significant innervation takes place during postnatal heart development, a period when cardiomyocytes undergo a rapid transition from proliferative to hypertrophic growth. The question of whether these innervating sympathetic fibres play a role in regulating the modes of cardiomyocyte growth was investigated using 6-hydroxydopamine (6-OHDA) to abolish early sympathetic innervation of the heart. Postnatal chemical sympathectomy resulted in rats with smaller hearts, indicating that heart growth is regulated by innervating sympathetic fibres during the postnatal period. In vitro experiments showed that sympathetic interactions resulted in delays in markers of cardiomyocyte maturation, suggesting that changes in the timing of the transition from hyperplastic to hypertrophic growth of cardiomyocytes could underlie changes in heart size in the sympathectomized animals. There was also an increase in the expression of Meis1, which has been linked to cardiomyocyte cell cycle withdrawal, suggesting that sympathetic signalling suppresses cell cycle withdrawal. This signalling involves β-adrenergic activation, which was necessary for sympathetic regulation of cardiomyocyte proliferation and hypertrophy. The effect of β-adrenergic signalling on cardiomyocyte hypertrophy underwent a developmental transition. While young postnatal cardiomyocytes responded to isoproterenol (isoprenaline) with a decrease in cell size, mature cardiomyocytes showed an increase in cell size in response to the drug. Together, these results suggest that early sympathetic effects on proliferation modulate a key transition between proliferative and hypertrophic growth of the heart and contribute to the sympathetic regulation of adult heart size. © 2015 The Authors. The Journal of Physiology © 2015 The Physiological Society.

  18. Maternal Embryonic Leucine Zipper Kinase (MELK: A Novel Regulator in Cell Cycle Control, Embryonic Development, and Cancer

    Directory of Open Access Journals (Sweden)

    Pengfei Jiang

    2013-10-01

    Full Text Available Maternal embryonic leucine zipper kinase (MELK functions as a modulator of intracellular signaling and affects various cellular and biological processes, including cell cycle, cell proliferation, apoptosis, spliceosome assembly, gene expression, embryonic development, hematopoiesis, and oncogenesis. In these cellular processes, MELK functions by binding to numerous proteins. In general, the effects of multiple protein interactions with MELK are oncogenic in nature, and the overexpression of MELK in kinds of cancer provides some evidence that it may be involved in tumorigenic process. In this review, our current knowledge of MELK function and recent discoveries in MELK signaling pathway were discussed. The regulation of MELK in cancers and its potential as a therapeutic target were also described.

  19. STK35L1 associates with nuclear actin and regulates cell cycle and migration of endothelial cells.

    Directory of Open Access Journals (Sweden)

    Pankaj Goyal

    Full Text Available BACKGROUND: Migration and proliferation of vascular endothelial cells are essential for repair of injured endothelium and angiogenesis. Cyclins, cyclin-dependent kinases (CDKs, and cyclin-dependent kinase inhibitors play an important role in vascular tissue injury and wound healing. Previous studies suggest a link between the cell cycle and cell migration: cells present in the G(1 phase have the highest potential to migrate. The molecular mechanism linking these two processes is not understood. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we explored the function of STK35L1, a novel Ser/Thr kinase, localized in the nucleus and nucleolus of endothelial cells. Molecular biological analysis identified a bipartite nuclear localization signal, and nucleolar localization sequences in the N-terminal part of STK35L1. Nuclear actin was identified as a novel binding partner of STK35L1. A class III PDZ binding domains motif was identified in STK35L1 that mediated its interaction with actin. Depletion of STK35L1 by siRNA lead to an accelerated G(1 to S phase transition after serum-stimulation of endothelial cells indicating an inhibitory role of the kinase in G(1 to S phase progression. Cell cycle specific genes array analysis revealed that one gene was prominently downregulated (8.8 fold in STK35L1 silenced cells: CDKN2A alpha transcript, which codes for p16(INK4a leading to G(1 arrest by inhibition of CDK4/6. Moreover in endothelial cells seeded on Matrigel, STK35L1 expression was rapidly upregulated, and silencing of STK35L1 drastically inhibited endothelial sprouting that is required for angiogenesis. Furthermore, STK35L1 depletion profoundly impaired endothelial cell migration in two wound healing assays. CONCLUSION/SIGNIFICANCE: The results indicate that by regulating CDKN2A and inhibiting G1- to S-phase transition STK35L1 may act as a central kinase linking the cell cycle and migration of endothelial cells. The interaction of STK35L1 with nuclear

  20. Model-based investigation of the circadian clock and cell cycle coupling in mouse embryonic fibroblasts: Prediction of RevErb-α up-regulation during mitosis.

    Science.gov (United States)

    Traynard, Pauline; Feillet, Céline; Soliman, Sylvain; Delaunay, Franck; Fages, François

    2016-11-01

    Experimental observations have put in evidence autonomous self-sustained circadian oscillators in most mammalian cells, and proved the existence of molecular links between the circadian clock and the cell cycle. Some mathematical models have also been built to assess conditions of control of the cell cycle by the circadian clock. However, recent studies in individual NIH3T3 fibroblasts have shown an unexpected acceleration of the circadian clock together with the cell cycle when the culture medium is enriched with growth factors, and the absence of such acceleration in confluent cells. In order to explain these observations, we study a possible entrainment of the circadian clock by the cell cycle through a regulation of clock genes around the mitosis phase. We develop a computational model and a formal specification of the observed behavior to investigate the conditions of entrainment in period and phase. We show that either the selective activation of RevErb-α or the selective inhibition of Bmal1 transcription during the mitosis phase, allow us to fit the experimental data on both period and phase, while a uniform inhibition of transcription during mitosis seems incompatible with the phase data. We conclude on the arguments favoring the RevErb-α up-regulation hypothesis and on some further predictions of the model. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  1. The KDM5 family is required for activation of pro-proliferative cell cycle genes during adipocyte differentiation

    DEFF Research Database (Denmark)

    Brier, Ann-Sofie B; Loft, Anne; Madsen, Jesper G S

    2017-01-01

    The KDM5 family of histone demethylases removes the H3K4 tri-methylation (H3K4me3) mark frequently found at promoter regions of actively transcribed genes and is therefore generally considered to contribute to corepression. In this study, we show that knockdown (KD) of all expressed members...... of the KDM5 family in white and brown preadipocytes leads to deregulated gene expression and blocks differentiation to mature adipocytes. KDM5 KD leads to a considerable increase in H3K4me3 at promoter regions; however, these changes in H3K4me3 have a limited effect on gene expression per se. By contrast......, genome-wide analyses demonstrate that KDM5A is strongly enriched at KDM5-activated promoters, which generally have high levels of H3K4me3 and are associated with highly expressed genes. We show that KDM5-activated genes include a large set of cell cycle regulators and that the KDM5s are necessary...

  2. RPS27a promotes proliferation, regulates cell cycle progression and inhibits apoptosis of leukemia cells

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Houcai; Yu, Jing; Zhang, Lixia; Xiong, Yuanyuan; Chen, Shuying; Xing, Haiyan; Tian, Zheng; Tang, Kejing; Wei, Hui; Rao, Qing; Wang, Min; Wang, Jianxiang, E-mail: wangjx@ihcams.ac.cn

    2014-04-18

    Highlights: • RPS27a expression was up-regulated in advanced-phase CML and AL patients. • RPS27a knockdown changed biological property of K562 and K562/G01 cells. • RPS27a knockdown affected Raf/MEK/ERK, P21 and BCL-2 signaling pathways. • RPS27a knockdown may be applicable for new combination therapy in CML patients. - Abstract: Ribosomal protein S27a (RPS27a) could perform extra-ribosomal functions besides imparting a role in ribosome biogenesis and post-translational modifications of proteins. The high expression level of RPS27a was reported in solid tumors, and we found that the expression level of RPS27a was up-regulated in advanced-phase chronic myeloid leukemia (CML) and acute leukemia (AL) patients. In this study, we explored the function of RPS27a in leukemia cells by using CML cell line K562 cells and its imatinib resistant cell line K562/G01 cells. It was observed that the expression level of RPS27a was high in K562 cells and even higher in K562/G01 cells. Further analysis revealed that RPS27a knockdown by shRNA in both K562 and K562G01 cells inhibited the cell viability, induced cell cycle arrest at S and G2/M phases and increased cell apoptosis induced by imatinib. Combination of shRNA with imatinib treatment could lead to more cleaved PARP and cleaved caspase-3 expression in RPS27a knockdown cells. Further, it was found that phospho-ERK(p-ERK) and BCL-2 were down-regulated and P21 up-regulated in RPS27a knockdown cells. In conclusion, RPS27a promotes proliferation, regulates cell cycle progression and inhibits apoptosis of leukemia cells. It appears that drugs targeting RPS27a combining with tyrosine kinase inhibitor (TKI) might represent a novel therapy strategy in TKI resistant CML patients.

  3. Auxins differentially regulate root system architecture and cell cycle protein levels in maize seedlings.

    Science.gov (United States)

    Martínez-de la Cruz, Enrique; García-Ramírez, Elpidio; Vázquez-Ramos, Jorge M; Reyes de la Cruz, Homero; López-Bucio, José

    2015-03-15

    Maize (Zea mays) root system architecture has a complex organization, with adventitious and lateral roots determining its overall absorptive capacity. To generate basic information about the earlier stages of root development, we compared the post-embryonic growth of maize seedlings germinated in water-embedded cotton beds with that of plants obtained from embryonic axes cultivated in liquid medium. In addition, the effect of four different auxins, namely indole-3-acetic acid (IAA), 1-naphthaleneacetic acid (NAA), indole-3-butyric acid (IBA) and 2,4-dichlorophenoxyacetic acid (2,4-D) on root architecture and levels of the heat shock protein HSP101 and the cell cycle proteins CKS1, CYCA1 and CDKA1 were analyzed. Our data show that during the first days after germination, maize seedlings develop several root types with a simultaneous and/or continuous growth. The post-embryonic root development started with the formation of the primary root (PR) and seminal scutellar roots (SSR) and then continued with the formation of adventitious crown roots (CR), brace roots (BR) and lateral roots (LR). Auxins affected root architecture in a dose-response fashion; whereas NAA and IBA mostly stimulated crown root formation, 2,4-D showed a strong repressing effect on growth. The levels of HSP101, CKS1, CYCA1 and CDKA in root and leaf tissues were differentially affected by auxins and interestingly, HSP101 registered an auxin-inducible and root specific expression pattern. Taken together, our results show the timing of early branching patterns of maize and indicate that auxins regulate root development likely through modulation of the HSP101 and cell cycle proteins. Copyright © 2014 Elsevier GmbH. All rights reserved.

  4. Integration of TP53, DREAM, MMB-FOXM1 and RB-E2F target gene analyses identifies cell cycle gene regulatory networks.

    Science.gov (United States)

    Fischer, Martin; Grossmann, Patrick; Padi, Megha; DeCaprio, James A

    2016-07-27

    Cell cycle (CC) and TP53 regulatory networks are frequently deregulated in cancer. While numerous genome-wide studies of TP53 and CC-regulated genes have been performed, significant variation between studies has made it difficult to assess regulation of any given gene of interest. To overcome the limitation of individual studies, we developed a meta-analysis approach to identify high confidence target genes that reflect their frequency of identification in independent datasets. Gene regulatory networks were generated by comparing differential expression of TP53 and CC-regulated genes with chromatin immunoprecipitation studies for TP53, RB1, E2F, DREAM, B-MYB, FOXM1 and MuvB. RNA-seq data from p21-null cells revealed that gene downregulation by TP53 generally requires p21 (CDKN1A). Genes downregulated by TP53 were also identified as CC genes bound by the DREAM complex. The transcription factors RB, E2F1 and E2F7 bind to a subset of DREAM target genes that function in G1/S of the CC while B-MYB, FOXM1 and MuvB control G2/M gene expression. Our approach yields high confidence ranked target gene maps for TP53, DREAM, MMB-FOXM1 and RB-E2F and enables prediction and distinction of CC regulation. A web-based atlas at www.targetgenereg.org enables assessing the regulation of any human gene of interest. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

  5. Cell-cycle-specific interaction of nuclear DNA-binding proteins with a CCAAT sequence from the human thymidine kinase gene

    International Nuclear Information System (INIS)

    Knight, G.B.; Gudas, J.M.; Pardee, A.B.

    1987-01-01

    Induction of thymidine kinase parallels the onset of DNA synthesis. To investigate the transcriptional regulation of the thymidine kinase gene, the authors have examined whether specific nuclear factors interact in a cell-cycle-dependent manner with sequences upstream of this gene. Two inverted CCAAT boxes near the transcriptional initiation sites were observed to form complexes with nuclear DNA-binding proteins. The nature of the complexes changes dramatically as the cells approach DNA synthesis and correlates well with the previously reported transcriptional increase of the thymidine kinase gene

  6. TGF-β Signaling Regulates Pancreatic β-Cell Proliferation through Control of Cell Cycle Regulator p27 Expression

    International Nuclear Information System (INIS)

    Suzuki, Tomoyuki; Dai, Ping; Hatakeyama, Tomoya; Harada, Yoshinori; Tanaka, Hideo; Yoshimura, Norio; Takamatsu, Tetsuro

    2013-01-01

    Proliferation of pancreatic β-cells is an important mechanism underlying β-cell mass adaptation to metabolic demands. Increasing β-cell mass by regeneration may ameliorate or correct both type 1 and type 2 diabetes, which both result from inadequate production of insulin by β-cells of the pancreatic islet. Transforming growth factor β (TGF-β) signaling is essential for fetal development and growth of pancreatic islets. In this study, we exposed HIT-T15, a clonal pancreatic β-cell line, to TGF-β signaling. We found that inhibition of TGF-β signaling promotes proliferation of the cells significantly, while TGF-β signaling stimulation inhibits proliferation of the cells remarkably. We confirmed that this proliferative regulation by TGF-β signaling is due to the changed expression of the cell cycle regulator p27. Furthermore, we demonstrated that there is no observed effect on transcriptional activity of p27 by TGF-β signaling. Our data show that TGF-β signaling mediates the cell-cycle progression of pancreatic β-cells by regulating the nuclear localization of CDK inhibitor, p27. Inhibition of TGF-β signaling reduces the nuclear accumulation of p27, and as a result this inhibition promotes proliferation of β-cells

  7. A Clb/Cdk1-mediated regulation of Fkh2 synchronizes CLB expression in the budding yeast cell cycle

    NARCIS (Netherlands)

    Linke, C.; Chasapi, A.; González-Novo, A.; Al Sawad, I.; Tognetti, S.; Klipp, E.; Loog, M.; Krobitsch, S.; Posas, F.; Xenarios, I.; Barberis, M.

    2017-01-01

    Precise timing of cell division is achieved by coupling waves of cyclin-dependent kinase (Cdk) activity with a transcriptional oscillator throughout cell cycle progression. Although details of transcription of cyclin genes are known, it is unclear which is the transcriptional cascade that modulates

  8. Promoter methylation patterns in Richter syndrome affect stem-cell maintenance and cell cycle regulation and differ from de novo diffuse large B-cell lymphoma.

    Science.gov (United States)

    Rinaldi, Andrea; Mensah, Afua Adjeiwaa; Kwee, Ivo; Forconi, Francesco; Orlandi, Ester M; Lucioni, Marco; Gattei, Valter; Marasca, Roberto; Berger, Françoise; Cogliatti, Sergio; Cavalli, Franco; Zucca, Emanuele; Gaidano, Gianluca; Rossi, Davide; Bertoni, Francesco

    2013-10-01

    In a fraction of patients, chronic lymphocytic leukaemia (CLL) can transform to Richter syndrome (RS), usually a diffuse large B-cell lymphoma (DLBCL). We studied genome-wide promoter DNA methylation in RS and clonally related CLL-phases of transformed patients, alongside de novo DLBCL (of non-germinal centre B type), untransformed-CLL and normal B-cells. The greatest differences in global DNA methylation levels were observed between RS and DLBCL, indicating that these two diseases, although histologically similar, are epigenetically distinct. RS was more highly methylated for genes involved in cell cycle regulation. When RS was compared to the preceding CLL-phase and with untransformed-CLL, RS presented a higher degree of methylation for genes possessing the H3K27me3 mark and PRC2 targets, as well as for gene targets of TP53 and RB1. Comparison of the methylation levels of individual genes revealed that OSM, a stem cell regulatory gene, exhibited significantly higher methylation levels in RS compared to CLL-phases. Its transcriptional repression by DNA methylation was confirmed by 5-aza-2'deoxycytidine treatment of DLBCL cells, determining an increased OSM expression. Our results showed that methylation patterns in RS are largely different from de novo DLBCL. Stem cell-related genes and cell cycle regulation genes are targets of DNA methylation in RS. © 2013 John Wiley & Sons Ltd.

  9. Occupational health hazards of trichloroethylene among workers in relation to altered mRNA expression of cell cycle regulating genes (p53, p21, bax and bcl-2 and PPARA

    Directory of Open Access Journals (Sweden)

    Meenu Varshney

    2015-01-01

    Full Text Available Trichloroethylene (TCE is widely used as a metal degreaser in industrial processes. The present study reports on the effects of TCE exposure on workers employed in the lock industries. To ensure exposure of the workers to TCE, its toxic metabolites, trichloroacetic acid (TCA, dichloroacetic acid (DCA and trichloroethanol (TCEOH were detected in the plasma of the subjects through solid phase microextraction-gas chromatography-electron capture detection. TCA, DCA and TCEOH were detected in the range of 0.004–2.494 μg/mL, 0.01–3.612 μg/mL and 0.002–0.617 μg/mL, respectively. Quantitative reverse transcription polymerase chain reaction analysis revealed up-regulated expression of p53 (2.4-fold; p < 0.05, p21 (2-fold; p < 0.01, bax (2.9-fold; p < 0.01 mRNAs and down-regulated expression of bcl-2 (67%; p < 0.05 mRNAs, indicating DNA damaging potential of these metabolites. No effects were observed on the levels of p16 and c-myc mRNAs. Further, as TCA and DCA, the ligand of peroxisome proliferator activated receptor alpha (PPARA, are involved in the process of hepatocarcinogenesis in rodents, we examined expression of PPARA mRNA and let-7c miRNA in the workers. No statistically significant differences in expression of PPARA mRNA and let-7c miRNA in patients were observed as compared to values in controls. Dehydroepiandosterone sulfate (DHEAS is a reported endogenous ligand of PPARA so its competitive role was also studied. We observed decreased levels of DHEAS hormone in the subjects. Hence, its involvement in mediation of the observed changes in the levels of various mRNAs analyzed in this study appears unlikely.

  10. Cell-cycle-dependent regulation of cell motility and determination of the role of Rac1

    DEFF Research Database (Denmark)

    Walmod, Peter S.; Hartmann-Petersen, Rasmus; Prag, S.

    2004-01-01

    comparable to those of control cells in G1. In contrast, transfection with dominant-negative Rac1 reduced cell speed and resulted in cellular displacements, which were identical in G1 and G2. These observations indicate that migration of cultured cells is regulated in a cell-cycle-dependent manner...... for calculation of three key parameters describing cell motility: speed, persistence time and rate of diffusion. All investigated cell lines demonstrated a lower cell displacement in the G2 phase than in the G1/S phases. This was caused by a decrease in speed and/or persistence time. The decrease in motility...... was accompanied by changes in morphology reflecting the larger volume of cells in G2 than in G1. Furthermore, L-cells and HeLa-cells appeared to be less adherent in the G2 phase. Transfection of L-cells with constitutively active Rac1 led to a general increase in the speed and rate of diffusion in G2 to levels...

  11. Mast cells dysregulate apoptotic and cell cycle genes in mucosal squamous cell carcinoma

    Directory of Open Access Journals (Sweden)

    Davis Paul

    2006-12-01

    Full Text Available Abstract Background Mucosal squamous cell carcinoma of the head and neck is a disease of high mortality and morbidity. Interactions between the squamous cell carcinoma and the host's local immunity, and how the latter contributes to the biological behavior of the tumor are unclear. In vivo studies have demonstrated sequential mast cell infiltration and degranulation during squamous cell carcinogenesis. The degree of mast cell activation correlates closely with distinct phases of hyperkeratosis, dysplasia, carcinoma in-situ and invasive carcinoma. However, the role of mast cells in carcinogenesis is unclear. Aim This study explores the effects of mast cells on the proliferation and gene expression profile of mucosal squamous cell carcinoma using human mast cell line (HMC-1 and human glossal squamous cell carcinoma cell line (SCC25. Methods HMC-1 and SCC25 were co-cultured in a two-compartment chamber, separated by a polycarbonate membrane. HMC-1 was stimulated to degranulate with calcium ionophore A23187. The experiments were done in quadruplicate. Negative controls were established where SCC25 were cultured alone without HMC-1. At 12, 24, 48 and 72 hours, proliferation and viability of SCC25 were assessed with MTT colorimetric assay. cDNA microarray was employed to study differential gene expression between co-cultured and control SCC25. Results HMC-1/SCC25 co-culture resulted in suppression of growth rate for SCC-25 (34% compared with 110% for the control by 72 hours, p Conclusion We show that mast cells have a direct inhibitory effect on the proliferation of mucosal squamous cell carcinoma in vitro by dysregulating key genes in apoptosis and cell cycle control.

  12. Nucleolin down-regulation is involved in ADP-induced cell cycle arrest in S phase and cell apoptosis in vascular endothelial cells.

    Directory of Open Access Journals (Sweden)

    Wenmeng Wang

    Full Text Available High concentration of extracellular ADP has been reported to induce cell apoptosis, but the molecular mechanisms remain not fully elucidated. In this study, we found by serendipity that ADP treatment of human umbilical vein endothelial cells (HUVEC and human aortic endothelial cells (HAEC down-regulated the protein level of nucleolin in a dose- and time-dependent manner. ADP treatment did not decrease the transcript level of nucloelin, suggesting that ADP might induce nucleolin protein degradation. HUVEC and HAEC expressed ADP receptor P2Y13 receptor, but did not express P2Y1 or P2Y12 receptors. However, P2Y1, 12, 13 receptor antagonists MRS2179, PSB0739, MRS2211 did not inhibit ADP-induced down-regulation of nucleolin. Moreover, MRS2211 itself down-regulated nucleolin protein level. In addition, 2-MeSADP, an agonist for P2Y1, 12 and 13 receptors, did not down-regulate nucleolin protein. These results suggested that ADP-induced nucleolin down-regulation was not due to the activation of P2Y1, 12, or 13 receptors. We also found that ADP treatment induced cell cycle arrest in S phase, cell apoptosis and cell proliferation inhibition via nucleolin down-regulation. The over-expression of nucleolin by gene transfer partly reversed ADP-induced cell cycle arrest, cell apoptosis and cell proliferation inhibition. Furthermore, ADP sensitized HUVEC to cisplatin-induced cell death by the down-regulation of Bcl-2 expression. Taken together, we found, for the first time to our knowledge, a novel mechanism by which ADP regulates cell proliferation by induction of cell cycle arrest and cell apoptosis via targeting nucelolin.

  13. Hepatitis C virus core protein expression leads to biphasic regulation of the p21 cdk inhibitor and modulation of hepatocyte cell cycle

    International Nuclear Information System (INIS)

    Nguyen, Hau; Mudryj, Maria; Guadalupe, Moraima; Dandekar, Satya

    2003-01-01

    Hepatitis C virus (HCV) Core protein is implicated in viral pathogenesis by the modulation of hepatocyte gene expression and function. To determine the effect of Core protein on the cell-cycle control of hepatocytes, a HepG2 cell line containing a Flag-tagged Core under the control of an inducible promoter was generated. Initial Core protein expression included the presence of unprocessed (191 aa) and processed (173 aa) forms of the Core proteins with the processed form becoming dominant later. Expression of the 191 aa form of Core protein corresponded to an increase in the expression of the p21, a decrease in cdk2-dependent kinase activity, and a decrease in the percentage of cells in S-phase along with an accumulation of cells in the G 0 /G 1 phase of the cell cycle. As the processed form accumulated, the p21 levels started to decline, suggesting that Core protein regulates p21 expression in a biphasic manner. These findings implicate Core protein in potentially modulating hepatocyte cell cycle differentially in the early stages of infection through biphasic regulation of p21 cdk kinase inhibitor

  14. Borealin/Dasra B is a cell cycle-regulated chromosomal passenger protein and its nuclear accumulation is linked to poor prognosis for human gastric cancer

    International Nuclear Information System (INIS)

    Chang, J.-L.; Chen, T.-H.; Wang, C.-F.; Chiang, Y.-H.; Huang, Y.-L.; Wong, F.-H.; Chou, C.-K.; Chen, C.-M.

    2006-01-01

    Chromosomal passenger proteins including Aurora B, Survivin, and Borealin/Dasra B, also called CDCA8/FLJ10468, are known to play crucial roles during mitosis and cell division. Inappropriate chromosomal segregation and cell division may cause auneuploidy leading to cancer. However, it is still unclear how the expression of chromosomal passenger proteins may be linked to cancer. In this study, we demonstrated that Borealin is a cell cycle-regulated gene and is upregulated at G2-M phases of the cell cycle. We showed that Borealin interacts with Survivin but not with Aurora B. The interaction domain of Survivin in Borealin was mapped to the N-terminal 92 amino-acid residues of Borealin. To examine the linkage between expression of Borealin and cancer, we performed immunohistochemistry analysis using anti-Borealin specific antibody on the paraffin-embedded gastric cancer tissues. Our results showed that Borealin expression is significantly correlated with Survivin (P = 0.003) and Ki67 (P = 0.007) in gastric cancer. Interestingly, an increased nuclear Borealin level reveals borderline association with a poor survival rate (P = 0.047). Taken together, our results demonstrated that Borealin is a cell cycle-regulated chromosomal passenger protein and its aberrant expression is linked to a poor prognosis for gastric cancer

  15. High content image based analysis identifies cell cycle inhibitors as regulators of Ebola virus infection.

    Science.gov (United States)

    Kota, Krishna P; Benko, Jacqueline G; Mudhasani, Rajini; Retterer, Cary; Tran, Julie P; Bavari, Sina; Panchal, Rekha G

    2012-09-25

    Viruses modulate a number of host biological responses including the cell cycle to favor their replication. In this study, we developed a high-content imaging (HCI) assay to measure DNA content and identify different phases of the cell cycle. We then investigated the potential effects of cell cycle arrest on Ebola virus (EBOV) infection. Cells arrested in G1 phase by serum starvation or G1/S phase using aphidicolin or G2/M phase using nocodazole showed much reduced EBOV infection compared to the untreated control. Release of cells from serum starvation or aphidicolin block resulted in a time-dependent increase in the percentage of EBOV infected cells. The effect of EBOV infection on cell cycle progression was found to be cell-type dependent. Infection of asynchronous MCF-10A cells with EBOV resulted in a reduced number of cells in G2/M phase with concomitant increase of cells in G1 phase. However, these effects were not observed in HeLa or A549 cells. Together, our studies suggest that EBOV requires actively proliferating cells for efficient replication. Furthermore, multiplexing of HCI based assays to detect viral infection, cell cycle status and other phenotypic changes in a single cell population will provide useful information during screening campaigns using siRNA and small molecule therapeutics.

  16. High Content Image Based Analysis Identifies Cell Cycle Inhibitors as Regulators of Ebola Virus Infection

    Directory of Open Access Journals (Sweden)

    Sina Bavari

    2012-09-01

    Full Text Available Viruses modulate a number of host biological responses including the cell cycle to favor their replication. In this study, we developed a high-content imaging (HCI assay to measure DNA content and identify different phases of the cell cycle. We then investigated the potential effects of cell cycle arrest on Ebola virus (EBOV infection. Cells arrested in G1 phase by serum starvation or G1/S phase using aphidicolin or G2/M phase using nocodazole showed much reduced EBOV infection compared to the untreated control. Release of cells from serum starvation or aphidicolin block resulted in a time-dependent increase in the percentage of EBOV infected cells. The effect of EBOV infection on cell cycle progression was found to be cell-type dependent. Infection of asynchronous MCF-10A cells with EBOV resulted in a reduced number of cells in G2/M phase with concomitant increase of cells in G1 phase. However, these effects were not observed in HeLa or A549 cells. Together, our studies suggest that EBOV requires actively proliferating cells for efficient replication. Furthermore, multiplexing of HCI based assays to detect viral infection, cell cycle status and other phenotypic changes in a single cell population will provide useful information during screening campaigns using siRNA and small molecule therapeutics.

  17. Immunohistochemical study of the expression of cell cycle regulating proteins at different stages of bladder cancer

    DEFF Research Database (Denmark)

    Primdahl, Hanne; von der Maase, Hans; Sørensen, Flemming Brandt

    2002-01-01

    PURPOSE: The cell cycle is known to be deregulated in cancer. We therefore analyzed the expression of the cell cycle related proteins p21, p27, p16, Rb, and L-myc by immunohistochemical staining of bladder tumors.METHODS: The tissue material consisted of bladder tumors from three groups of patients......; group 1, 23 patients with recurrent stage Ta (non-invasive) tumors; group 2, 22 patients presenting at their first admission with T2-4 (muscle invasive) tumors; group 3, 24 patients who experienced disease progression from Ta or T1 (invasive in connective tissue) to a higher stage...

  18. A Stochastic Model of the Yeast Cell Cycle Reveals Roles for Feedback Regulation in Limiting Cellular Variability.

    Science.gov (United States)

    Barik, Debashis; Ball, David A; Peccoud, Jean; Tyson, John J

    2016-12-01

    The cell division cycle of eukaryotes is governed by a complex network of cyclin-dependent protein kinases (CDKs) and auxiliary proteins that govern CDK activities. The control system must function reliably in the context of molecular noise that is inevitable in tiny yeast cells, because mistakes in sequencing cell cycle events are detrimental or fatal to the cell or its progeny. To assess the effects of noise on cell cycle progression requires not only extensive, quantitative, experimental measurements of cellular heterogeneity but also comprehensive, accurate, mathematical models of stochastic fluctuations in the CDK control system. In this paper we provide a stochastic model of the budding yeast cell cycle that accurately accounts for the variable phenotypes of wild-type cells and more than 20 mutant yeast strains simulated in different growth conditions. We specifically tested the role of feedback regulations mediated by G1- and SG2M-phase cyclins to minimize the noise in cell cycle progression. Details of the model are informed and tested by quantitative measurements (by fluorescence in situ hybridization) of the joint distributions of mRNA populations in yeast cells. We use the model to predict the phenotypes of ~30 mutant yeast strains that have not yet been characterized experimentally.

  19. A Stochastic Model of the Yeast Cell Cycle Reveals Roles for Feedback Regulation in Limiting Cellular Variability.

    Directory of Open Access Journals (Sweden)

    Debashis Barik

    2016-12-01

    Full Text Available The cell division cycle of eukaryotes is governed by a complex network of cyclin-dependent protein kinases (CDKs and auxiliary proteins that govern CDK activities. The control system must function reliably in the context of molecular noise that is inevitable in tiny yeast cells, because mistakes in sequencing cell cycle events are detrimental or fatal to the cell or its progeny. To assess the effects of noise on cell cycle progression requires not only extensive, quantitative, experimental measurements of cellular heterogeneity but also comprehensive, accurate, mathematical models of stochastic fluctuations in the CDK control system. In this paper we provide a stochastic model of the budding yeast cell cycle that accurately accounts for the variable phenotypes of wild-type cells and more than 20 mutant yeast strains simulated in different growth conditions. We specifically tested the role of feedback regulations mediated by G1- and SG2M-phase cyclins to minimize the noise in cell cycle progression. Details of the model are informed and tested by quantitative measurements (by fluorescence in situ hybridization of the joint distributions of mRNA populations in yeast cells. We use the model to predict the phenotypes of ~30 mutant yeast strains that have not yet been characterized experimentally.

  20. CDKL5, a novel MYCN-repressed gene, blocks cell cycle and promotes differentiation of neuronal cells.

    Science.gov (United States)

    Valli, Emanuele; Trazzi, Stefania; Fuchs, Claudia; Erriquez, Daniela; Bartesaghi, Renata; Perini, Giovanni; Ciani, Elisabetta

    2012-01-01

    Mutations in the CDKL5 (cyclin-dependent kinase-like 5) gene are associated with a severe epileptic encephalopathy (early infantile epileptic encephalopathy type 2, EIEE2) characterized by early-onset intractable seizures, infantile spasms, severe developmental delay, intellectual disability, and Rett syndrome (RTT)-like features. Despite the clear involvement of CDKL5 mutations in intellectual disability, the function of this protein during brain development and the molecular mechanisms involved in its regulation are still unknown. Using human neuroblastoma cells as a model system we found that an increase in CDKL5 expression caused an arrest of the cell cycle in the G(0)/G(1) phases and induced cellular differentiation. Interestingly, CDKL5 expression was inhibited by MYCN, a transcription factor that promotes cell proliferation during brain development and plays a relevant role in neuroblastoma biology. Through a combination of different and complementary molecular and cellular approaches we could show that MYCN acts as a direct repressor of the CDKL5 promoter. Overall our findings unveil a functional axis between MYCN and CDKL5 governing both neuron proliferation rate and differentiation. The fact that CDKL5 is involved in the control of both neuron proliferation and differentiation may help understand the early appearance of neurological symptoms in patients with mutations in CDKL5. Copyright © 2012 Elsevier B.V. All rights reserved.

  1. Distinctive adaptive response to repeated exposure to hydrogen peroxide associated with upregulation of DNA repair genes and cell cycle arrest

    Directory of Open Access Journals (Sweden)

    Gloria A. Santa-Gonzalez

    2016-10-01

    Full Text Available Many environmental and physiological stresses are chronic. Thus, cells are constantly exposed to diverse types of genotoxic insults that challenge genome stability, including those that induce oxidative DNA damage. However, most in vitro studies that model cellular response to oxidative stressors employ short exposures and/or acute stress models. In this study, we tested the hypothesis that chronic and repeated exposure to a micromolar concentration of hydrogen peroxide (H2O2 could activate DNA damage responses, resulting in cellular adaptations. For this purpose, we developed an in vitro model in which we incubated mouse myoblast cells with a steady concentration of ~50 μM H2O2 for one hour daily for seven days, followed by a final challenge of a 10 or 20X higher dose of H2O2 (0.5 or 1 mM. We report that intermittent long-term exposure to this oxidative stimulus nearly eliminated cell toxicity and significantly decreased genotoxicity (in particular, a >5-fold decreased in double-strand breaks resulting from subsequent acute exposure to oxidative stress. This protection was associated with cell cycle arrest in G2/M and induction of expression of nine DNA repair genes. Together, this evidence supports an adaptive response to chronic, low-level oxidative stress that results in genomic protection and up-regulated maintenance of cellular homeostasis.

  2. Cyclebase 3.0: a multi-organism database on cell-cycle regulation and phenotypes

    DEFF Research Database (Denmark)

    Santos Delgado, Alberto; Wernersson, Rasmus; Jensen, Lars Juhl

    2015-01-01

    3.0, we have updated the content of the database to reflect changes to genome annotation, added new mRNAand protein expression data, and integrated cell-cycle phenotype information from high-content screens and model-organism databases. The new version of Cyclebase also features a new web interface...

  3. Outside-in control -Does plant cell wall integrity regulate cell cycle progression?

    Science.gov (United States)

    Gigli-Bisceglia, Nora; Hamann, Thorsten

    2018-04-13

    During recent years it has become accepted that plant cell walls are not inert objects surrounding all plant cells but are instead highly dynamic, plastic structures. They are involved in a large number of cell biological processes and contribute actively to plant growth, development and interaction with environment. Therefore, it is not surprising that cellular processes can control plant cell wall integrity while, simultaneously, cell wall integrity can influence cellular processes. In yeast and animal cells such a bi-directional relationship also exists between the yeast/animal extra-cellular matrices and the cell cycle. In yeast, the cell wall integrity maintenance mechanism and a dedicated plasmamembrane integrity checkpoint are mediating this relationship. Recent research has yielded insights into the mechanism controlling plant cell wall metabolism during cytokinesis. However, knowledge regarding putative regulatory pathways controlling adaptive modifications in plant cell cycle activity in response to changes in the state of the plant cell wall are not yet identified. In this review, we summarize similarities and differences in regulatory mechanisms coordinating extra cellular matrices and cell cycle activity in animal and yeast cells, discuss the available evidence supporting the existence of such a mechanism in plants and suggest that the plant cell wall integrity maintenance mechanism might also control cell cycle activity in plant cells. This article is protected by copyright. All rights reserved.

  4. MicroRNA-139-5p acts as a tumor suppressor by targeting ELTD1 and regulating cell cycle in glioblastoma multiforme

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Shouping [Department of Diagnostic Imaging, Linyi People' s Hospital, Linyi, Shandong 276000 (China); Wang, Xianjun [Department of Neurology, Linyi People' s Hospital, Linyi, Shandong 276000 (China); Li, Xiao [Department of Pathology, First Affiliated Hospital of Nanjing Medical University, Nanjing (China); Cao, Yuandong, E-mail: yuandongcao@sina.com [Department of Radiotherapy, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province (China)

    2015-11-13

    MicroRNA-139-5p was identified to be significantly down-regulated in glioblastoma multiform (GBM) by miRNA array. In this report we aimed to clarify its biological function, molecular mechanisms and direct target gene in GBM. Twelve patients with GBM were analyzed for the expression of miR-139-5p by quantitative RT-PCR. miR-139-5p overexpression was established by transfecting miR-139-5p-mimic into U87MG and T98G cells, and its effects on cell proliferation were studied using MTT assay and colony formation assays. We concluded that ectopic expression of miR-139-5p in GBM cell lines significantly suppressed cell proliferation and inducing apoptosis. Bioinformatics coupled with luciferase and western blot assays also revealed that miR-139-5p suppresses glioma cell proliferation by targeting ELTD1 and regulating cell cycle. - Highlights: • miR-139-5p is downregulated in GBM. • miR-139-5p regulates cell proliferation through inducing apoptosis. • miR-139-5p regulates glioblastoma tumorigenesis by targeting 3′UTR of ELTD1. • miR-139-5p is involved in cell cycle regulation.

  5. Rhizoma Dioscoreae extract protects against alveolar bone loss by regulating the cell cycle: A predictive study based on the protein‑protein interaction network.

    Science.gov (United States)

    Zhang, Zhi-Guo; Song, Chang-Heng; Zhang, Fang-Zhen; Chen, Yan-Jing; Xiang, Li-Hua; Xiao, Gary Guishan; Ju, Da-Hong

    2016-06-01

    Rhizoma Dioscoreae extract (RDE) exhibits a protective effect on alveolar bone loss in ovariectomized (OVX) rats. The aim of this study was to predict the pathways or targets that are regulated by RDE, by re‑assessing our previously reported data and conducting a protein‑protein interaction (PPI) network analysis. In total, 383 differentially expressed genes (≥3‑fold) between alveolar bone samples from the RDE and OVX group rats were identified, and a PPI network was constructed based on these genes. Furthermore, four molecular clusters (A‑D) in the PPI network with the smallest P‑values were detected by molecular complex detection (MCODE) algorithm. Using Database for Annotation, Visualization and Integrated Discovery (DAVID) and Ingenuity Pathway Analysis (IPA) tools, two molecular clusters (A and B) were enriched for biological process in Gene Ontology (GO). Only cluster A was associated with biological pathways in the IPA database. GO and pathway analysis results showed that cluster A, associated with cell cycle regulation, was the most important molecular cluster in the PPI network. In addition, cyclin‑dependent kinase 1 (CDK1) may be a key molecule achieving the cell‑cycle‑regulatory function of cluster A. From the PPI network analysis, it was predicted that delayed cell cycle progression in excessive alveolar bone remodeling via downregulation of CDK1 may be another mechanism underling the anti‑osteopenic effect of RDE on alveolar bone.

  6. Temporal Gradient in the Clock Gene and Cell-Cycle Checkpoint Kinase Wee1 Expression along the Gut

    Czech Academy of Sciences Publication Activity Database

    Polidarová, Lenka; Soták, Matúš; Sládek, Martin; Pácha, Jiří; Sumová, Alena

    2009-01-01

    Roč. 26, č. 4 (2009), s. 607-620 ISSN 0742-0528 R&D Projects: GA AV ČR(CZ) IAA500110605; GA ČR(CZ) GA305/09/0321; GA MŠk(CZ) LC554 EU Projects: European Commission(XE) 18741 - EUCLOCK Institutional research plan: CEZ:AV0Z50110509 Keywords : intestine epithelium * circadian clock gene * cell cycle Subject RIV: ED - Physiology Impact factor: 3.987, year: 2009

  7. Modulation of gene expression and cell-cycle signaling pathways by the EGFR inhibitor gefitinib (Iressa) in rat urinary bladder cancer.

    Science.gov (United States)

    Lu, Yan; Liu, Pengyuan; Van den Bergh, Francoise; Zellmer, Victoria; James, Michael; Wen, Weidong; Grubbs, Clinton J; Lubet, Ronald A; You, Ming

    2012-02-01

    The epidermal growth factor receptor inhibitor Iressa has shown strong preventive efficacy in the N-butyl-N-(4-hydroxybutyl)-nitrosamine (OH-BBN) model of bladder cancer in the rat. To explore its antitumor mechanism, we implemented a systems biology approach to characterize gene expression and signaling pathways in rat urinary bladder cancers treated with Iressa. Eleven bladder tumors from control rats, seven tumors from rats treated with Iressa, and seven normal bladder epithelia were profiled by the Affymetrix Rat Exon 1.0 ST Arrays. We identified 713 downregulated and 641 upregulated genes in comparing bladder tumors versus normal bladder epithelia. In addition, 178 genes were downregulated and 96 genes were upregulated when comparing control tumors versus Iressa-treated tumors. Two coexpression modules that were significantly correlated with tumor status and treatment status were identified [r = 0.70, P = 2.80 × 10(-15) (bladder tumor vs. normal bladder epithelium) and r = 0.63, P = 2.00 × 10(-42) (Iressa-treated tumor vs. control tumor), respectively]. Both tumor module and treatment module were enriched for genes involved in cell-cycle processes. Twenty-four and twenty-one highly connected hub genes likely to be key drivers in cell cycle were identified in the tumor module and treatment module, respectively. Analysis of microRNA genes on the array chips showed that tumor module and treatment module were significantly associated with expression levels of let-7c (r = 0.54, P = 3.70 × 10(-8) and r = 0.73, P = 1.50 × 10(-65), respectively). These results suggest that let-7c downregulation and its regulated cell-cycle pathway may play an integral role in governing bladder tumor suppression or collaborative oncogenesis and that Iressa exhibits its preventive efficacy on bladder tumorigenesis by upregulating let-7 and inhibiting the cell cycle. Cell culture study confirmed that the increased expression of let-7c decreases Iressa-treated bladder tumor cell

  8. Cell cycle-dependent regulation of kainate-induced inward currents in microglia

    International Nuclear Information System (INIS)

    Yamada, Jun; Sawada, Makoto; Nakanishi, Hiroshi

    2006-01-01

    Microglia are reported to have α-amino-hydroxy-5-methyl-isoxazole-4-propionate/kainate (KA) types. However, only small population of primary cultured rat microglia (approximately 20%) responded to KA. In the present study, we have attempted to elucidate the regulatory mechanism of responsiveness to KA in GMIR1 rat microglial cell line. When the GMIR1 cells were plated at a low density in the presence of granulocyte macrophage colony-stimulating factor, the proliferation rate increased and reached the peak after 2 days in culture and then gradually decreased because of density-dependent inhibition. At cell proliferation stage, approximately 80% of the GMIR1 cells exhibited glutamate (Glu)- and KA-induced inward currents at cell proliferation stage, whereas only 22.5% of the cells showed responsiveness to Glu and KA at cell quiescent stage. Furthermore, the mean amplitudes of inward currents induced by Glu and KA at cell proliferation stage (13.8 ± 3.0 and 8.4 ± 0.6 pA) were significantly larger than those obtained at cell quiescent stage (4.7 ± 0.8 and 6.2 ± 1.2 pA). In the GMIR1 cells, KA-induced inward currents were markedly inhibited by (RS)-3-(2-carboxybenzyl) willardiine (UBP296), a selective antagonist for KA receptors. The KA-responsive cells also responded to (RS)-2-amino-3-(3-hydroxy-5-tert-butylisoxazol-4-yl) propanoic acid (ATPA), a selective agonist for GluR5, in both GMIR1 cells and primary cultured rat microglia. Furthermore, mRNA levels of the KA receptor subunits, GluR5 and GluR6, at the cell proliferation stage were significantly higher than those at the cell quiescent stage. Furthermore, the immunoreactivity for GluR6/7 was found to increase in activated microglia in the post-ischemic hippocampus. These results strongly suggest that microglia have functional KA receptors mainly consisting of GluR5 and GluR6, and the expression levels of these subunits are closely regulated by the cell cycle mechanism

  9. Bevacizumab inhibits proliferation of choroidal endothelial cells by regulation of the cell cycle.

    Science.gov (United States)

    Rusovici, Raluca; Patel, Chirag J; Chalam, Kakarla V

    2013-01-01

    The purpose of this study was to evaluate cell cycle changes in choroidal endothelial cells treated with varying doses of bevacizumab in the presence of a range of concentrations of vascular endothelial growth factor (VEGF). Bevacizumab, a drug widely used in the treatment of neovascular age-related macular degeneration, choroidal neovascularization, and proliferative diabetic retinopathy, neutralizes all isoforms of VEGF. However, the effect of intravitreal administration of bevacizumab on the choroidal endothelial cell cycle has not been established. Monkey choroidal endothelial (RF/6A) cells were treated with VEGF 50 ng/mL and escalating doses of bevacizumab 0.1-2 mg/mL for 72 hours. Cell cycle changes in response to bevacizumab were analyzed by flow cytometry and propidium iodide staining. Cell proliferation was measured using the WST-1 assay. Morphological changes were recorded by bright field cell microscopy. Bevacizumab inhibited proliferation of choroidal endothelial cells by stabilization of the cell cycle in G0/G1 phase. Cell cycle analysis of VEGF-enriched choroidal endothelial cells revealed a predominant increase in the G2/M population (21.84%, P, 0.01) and a decrease in the G0/G1 phase population (55.08%, P, 0.01). Addition of escalating doses of bevacizumab stabilized VEGF-enriched cells in the G0/G1 phase (55.08%, 54.49%, 56.3%, and 64% [P, 0.01]) and arrested proliferation by inhibiting the G2/M phase (21.84%, 21.46%, 20.59%, 20.94%, and 16.1% [P, 0.01]). The increase in G0/G1 subpopulation in VEGF-enriched and bevacizumab-treated cells compared with VEGF-enriched cells alone was dose-dependent. Bevacizumab arrests proliferation of VEGF-enriched choroidal endothelial cells by stabilizing the cell cycle in the G0/G1 phase and inhibiting the G2/M phase in a dose-dependent fashion.

  10. MicroRNA-302/367 Cluster Governs hESC Self-Renewal by Dually Regulating Cell Cycle and Apoptosis Pathways

    Directory of Open Access Journals (Sweden)

    Zhonghui Zhang

    2015-04-01

    Full Text Available miR-302/367 is the most abundant miRNA cluster in human embryonic stem cells (hESCs and can promote somatic cell reprogramming. However, its role in hESCs remains poorly understood. Here, we studied functional roles of the endogenous miR-302/367 cluster in hESCs by employing specific TALE-based transcriptional repressors. We revealed that miR-302/367 cluster dually regulates hESC cell cycle and apoptosis in dose-dependent manner. Gene profiling and functional studies identified key targets of the miR-302/367 cluster in regulating hESC self-renewal and apoptosis. We demonstrate that in addition to its role in cell cycle regulation, miR-302/367 cluster conquers apoptosis by downregulating BNIP3L/Nix (a BH3-only proapoptotic factor and upregulating BCL-xL expression. Furthermore, we show that butyrate, a natural compound, upregulates miR-302/367 cluster expression and alleviates hESCs from apoptosis induced by knockdown of miR-302/367 cluster. In summary, our findings provide new insights in molecular mechanisms of how miR-302/367 cluster regulates hESCs.

  11. The regulation effect of STAT 5 signaling pathway on the cell cycle progression of irradiated KG-1 cells

    International Nuclear Information System (INIS)

    Guo Dehuang; Dong Bo; Luo Qingliang; Wen Gengyun; Mao Bingzhi

    2000-01-01

    The author investigated the role of the JAK/STAT signaling pathway regulating cell cycle progression in the irradiated KG-1 cells. By permanent transfecting the cells with DN-STAT 5 cDNA to block the JAK/STAT signaling pathway and then transient transfecting with cyclin D 1 or cyclin B 1 cDNA, the effects of cyclin D 1 protein and cyclin B 1 protein on the cell cycle progression were examined. Results showed that after irradiation with 8Gy 60 Co rays, the irradiated KG-1 cells transfected with only DN-STAT 5 cDNA can not recover form the G 1 arrest, even though GM-CSF was added. Meanwhile, the cells transfected with both the DN-STAT 5 cDNA and cyclin D 1 cDNA or cyclin B 1 cDNA can recover from the G 1 arrest or the G 2 arrest to a great extent. Thus, it was proved indirectly that the JAK/STAT signaling pathway activated by GM-CSF regulated the cell cycle progression through cyclin D 1 and cyclin B 1 protein

  12. Cytoplasmic pH and the regulation of the dictyostelium cell cycle

    NARCIS (Netherlands)

    Aerts, R.J.; Durston, A.J.; Moolenaar, W.H.

    1985-01-01

    Cytoplasmic pH (pHl) was monitored during the cell cycle of synchronous populations of Dictyostelium discoideum by means of a pH “null point” method. There is a cycle of pHl that closely corresponds to the DNA replication cycle, with a minimum of pH 7.20 in interphase and a peak of pH 7.45 during S

  13. Arabidopsis EST1/SMG7-like protein is a novel regulator of meiotic cell cycle progression

    Czech Academy of Sciences Publication Activity Database

    Riehs, N.; Akimcheva, S.; Bulánková, P.; Idol, R.; Široký, Jiří; Shippen, D.; Schweizer, D.; Říha, K.

    2007-01-01

    Roč. 274, č. 1 (2007), s. 71 ISSN 1742-464X. [32nd FEBS Congress - Molecular Machines. 07.07.2007-12.07.2007, Vienna] R&D Projects: GA ČR(CZ) GA522/06/0380 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : meiosis * Arabidopsis * cell cycle Subject RIV: BO - Biophysics

  14. Molecular conservation of estrogen-response associated with cell cycle regulation, hormonal carcinogenesis and cancer in zebrafish and human cancer cell lines

    Directory of Open Access Journals (Sweden)

    Govindarajan Kunde R

    2011-05-01

    Full Text Available Abstract Background The zebrafish is recognized as a versatile cancer and drug screening model. However, it is not known whether the estrogen-responsive genes and signaling pathways that are involved in estrogen-dependent carcinogenesis and human cancer are operating in zebrafish. In order to determine the potential of zebrafish model for estrogen-related cancer research, we investigated the molecular conservation of estrogen responses operating in both zebrafish and human cancer cell lines. Methods Microarray experiment was performed on zebrafish exposed to estrogen (17β-estradiol; a classified carcinogen and an anti-estrogen (ICI 182,780. Zebrafish estrogen-responsive genes sensitive to both estrogen and anti-estrogen were identified and validated using real-time PCR. Human homolog mapping and knowledge-based data mining were performed on zebrafish estrogen responsive genes followed by estrogen receptor binding site analysis and comparative transcriptome analysis with estrogen-responsive human cancer cell lines (MCF7, T47D and Ishikawa. Results Our transcriptome analysis captured multiple estrogen-responsive genes and signaling pathways that increased cell proliferation, promoted DNA damage and genome instability, and decreased tumor suppressing effects, suggesting a common mechanism for estrogen-induced carcinogenesis. Comparative analysis revealed a core set of conserved estrogen-responsive genes that demonstrate enrichment of estrogen receptor binding sites and cell cycle signaling pathways. Knowledge-based and network analysis led us to propose that the mechanism involving estrogen-activated estrogen receptor mediated down-regulation of human homolog HES1 followed by up-regulation cell cycle-related genes (human homologs E2F4, CDK2, CCNA, CCNB, CCNE, is highly conserved, and this mechanism may involve novel crosstalk with basal AHR. We also identified mitotic roles of polo-like kinase as a conserved signaling pathway with multiple entry

  15. Function and Regulation of Yeast Ribonucleotide Reductase: Cell Cycle, Genotoxic Stress, and Iron Bioavailability

    Directory of Open Access Journals (Sweden)

    Nerea Sanvisens

    2013-04-01

    Full Text Available Ribonucleotide reductases (RNRs are essential enzymes that catalyze the reduction of ribonucleotides to desoxyribonucleotides, thereby providing the building blocks required for de novo DNA biosynthesis. The RNR function is tightly regulated because an unbalanced or excessive supply of deoxyribonucleoside triphosphates (dNTPs dramatically increases the mutation rates during DNA replication and repair that can lead to cell death or genetic anomalies. In this review, we focus on Saccharomyces cerevisiae class Ia RNR as a model to understand the different mechanisms controlling RNR function and regulation in eukaryotes. Many studies have contributed to our current understanding of RNR allosteric regulation and, more recently, to its link to RNR oligomerization. Cells have developed additional mechanisms that restrict RNR activity to particular periods when dNTPs are necessary, such as the S phase or upon genotoxic stress. These regulatory strategies include the transcriptional control of the RNR gene expression, inhibition of RNR catalytic activity, and the subcellular redistribution of RNR subunits. Despite class Ia RNRs requiring iron as an essential cofactor for catalysis, little is known about RNR function regulation depending on iron bioavailability. Recent studies into yeast have deciphered novel strategies for the delivery of iron to RNR and for its regulation in response to iron deficiency. Taken together, these studies open up new possibilities to explore in order to limit uncontrolled tumor cell proliferation via RNR.

  16. A Model of Yeast Cell-Cycle Regulation Based on a Standard Component Modeling Strategy for Protein Regulatory Networks.

    Directory of Open Access Journals (Sweden)

    Teeraphan Laomettachit

    Full Text Available To understand the molecular mechanisms that regulate cell cycle progression in eukaryotes, a variety of mathematical modeling approaches have been employed, ranging from Boolean networks and differential equations to stochastic simulations. Each approach has its own characteristic strengths and weaknesses. In this paper, we propose a "standard component" modeling strategy that combines advantageous features of Boolean networks, differential equations and stochastic simulations in a framework that acknowledges the typical sorts of reactions found in protein regulatory networks. Applying this strategy to a comprehensive mechanism of the budding yeast cell cycle, we illustrate the potential value of standard component modeling. The deterministic version of our model reproduces the phenotypic properties of wild-type cells and of 125 mutant strains. The stochastic version of our model reproduces the cell-to-cell variability of wild-type cells and the partial viability of the CLB2-dbΔ clb5Δ mutant strain. Our simulations show that mathematical modeling with "standard components" can capture in quantitative detail many essential properties of cell cycle control in budding yeast.

  17. Cell cycle- and chaperone-mediated regulation of H3K56ac incorporation in yeast.

    Science.gov (United States)

    Kaplan, Tommy; Liu, Chih Long; Erkmann, Judith A; Holik, John; Grunstein, Michael; Kaufman, Paul D; Friedman, Nir; Rando, Oliver J

    2008-11-01

    Acetylation of histone H3 lysine 56 is a covalent modification best known as a mark of newly replicated chromatin, but it has also been linked to replication-independent histone replacement. Here, we measured H3K56ac levels at single-nucleosome resolution in asynchronously growing yeast cultures, as well as in yeast proceeding synchronously through the cell cycle. We developed a quantitative model of H3K56ac kinetics, which shows that H3K56ac is largely explained by the genomic replication timing and the turnover rate of each nucleosome, suggesting that cell cycle profiles of H3K56ac should reveal most first-time nucleosome incorporation events. However, since the deacetylases Hst3/4 prevent use of H3K56ac as a marker for histone deposition during M phase, we also directly measured M phase histone replacement rates. We report a global decrease in turnover rates during M phase and a further specific decrease in turnover at several early origins of replication, which switch from rapidly replaced in G1 phase to stably bound during M phase. Finally, by measuring H3 replacement in yeast deleted for the H3K56 acetyltransferase Rtt109 and its two co-chaperones Asf1 and Vps75, we find evidence that Rtt109 and Asf1 preferentially enhance histone replacement at rapidly replaced nucleosomes, whereas Vps75 appears to inhibit histone turnover at those loci. These results provide a broad perspective on histone replacement/incorporation throughout the cell cycle and suggest that H3K56 acetylation provides a positive-feedback loop by which replacement of a nucleosome enhances subsequent replacement at the same location.

  18. Cell cycle- and chaperone-mediated regulation of H3K56ac incorporation in yeast.

    Directory of Open Access Journals (Sweden)

    Tommy Kaplan

    2008-11-01

    Full Text Available Acetylation of histone H3 lysine 56 is a covalent modification best known as a mark of newly replicated chromatin, but it has also been linked to replication-independent histone replacement. Here, we measured H3K56ac levels at single-nucleosome resolution in asynchronously growing yeast cultures, as well as in yeast proceeding synchronously through the cell cycle. We developed a quantitative model of H3K56ac kinetics, which shows that H3K56ac is largely explained by the genomic replication timing and the turnover rate of each nucleosome, suggesting that cell cycle profiles of H3K56ac should reveal most first-time nucleosome incorporation events. However, since the deacetylases Hst3/4 prevent use of H3K56ac as a marker for histone deposition during M phase, we also directly measured M phase histone replacement rates. We report a global decrease in turnover rates during M phase and a further specific decrease in turnover at several early origins of replication, which switch from rapidly replaced in G1 phase to stably bound during M phase. Finally, by measuring H3 replacement in yeast deleted for the H3K56 acetyltransferase Rtt109 and its two co-chaperones Asf1 and Vps75, we find evidence that Rtt109 and Asf1 preferentially enhance histone replacement at rapidly replaced nucleosomes, whereas Vps75 appears to inhibit histone turnover at those loci. These results provide a broad perspective on histone replacement/incorporation throughout the cell cycle and suggest that H3K56 acetylation provides a positive-feedback loop by which replacement of a nucleosome enhances subsequent replacement at the same location.

  19. Role of insulin-like growth factor-1 (IGF-1) in regulating cell cycle progression

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Qi-lin; Yang, Tian-lun [Department of Cardiology, Xiangya Hospital, Central South University, Changsha 410008, Hunan (China); Yin, Ji-ye [Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Xiangya School of Medicine, Central South University, Changsha 410078, Hunan (China); Peng, Zhen-yu [Department of Cardiology, Xiangya Hospital, Central South University, Changsha 410008, Hunan (China); Yu, Min [Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Xiangya School of Medicine, Central South University, Changsha 410078, Hunan (China); Liu, Zhao-qian, E-mail: liuzhaoqian63@126.com [Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Xiangya School of Medicine, Central South University, Changsha 410078, Hunan (China); Chen, Fang-ping, E-mail: xychenfp@public.cs.hn.Cn [Department of Haematology, Xiangya Hospital, Central South University, Changsha 410008, Hunan (China)

    2009-11-06

    Aims: Insulin-like growth factor-1 (IGF-1) is a polypeptide protein hormone, similar in molecular structure to insulin, which plays an important role in cell migration, cell cycle progression, cell survival and proliferation. In this study, we investigated the possible mechanisms of IGF-1 mediated cell cycle redistribution and apoptosis of vascular endothelial cells. Method: Human umbilical vein endothelial cells (HUVECs) were pretreated with 0.1, 0.5, or 2.5 {mu}g/mL of IGF-1 for 30 min before the addition of Ang II. Cell cycle redistribution and apoptosis were examined by flow cytometry. Expression of Ang II type 1 (AT{sub 1}) mRNA and cyclin E protein were determined by RT-PCR and Western blot, respectively. Results: Ang II (1 {mu}mol/L) induced HUVECs arrested at G{sub 0}/G{sub 1}, enhanced the expression level of AT{sub 1} mRNA in a time-dependent manner, reduced the enzymatic activity of nitric oxide synthase (NOS) and nitric oxide (NO) content as well as the expression level of cyclin E protein. However, IGF-1 enhanced NOS activity, NO content, and the expression level of cyclin E protein, and reduced the expression level of AT{sub 1} mRNA. L-NAME significantly counteracted these effects of IGF-1. Conclusions: Our data suggests that IGF-1 can reverse vascular endothelial cells arrested at G{sub 0}/G{sub 1} and apoptosis induced by Ang II, which might be mediated via a NOS-NO signaling pathway and is likely associated with the expression levels of AT1 mRNA and cyclin E proteins.

  20. Role of insulin-like growth factor-1 (IGF-1) in regulating cell cycle progression

    International Nuclear Information System (INIS)

    Ma, Qi-lin; Yang, Tian-lun; Yin, Ji-ye; Peng, Zhen-yu; Yu, Min; Liu, Zhao-qian; Chen, Fang-ping

    2009-01-01

    Aims: Insulin-like growth factor-1 (IGF-1) is a polypeptide protein hormone, similar in molecular structure to insulin, which plays an important role in cell migration, cell cycle progression, cell survival and proliferation. In this study, we investigated the possible mechanisms of IGF-1 mediated cell cycle redistribution and apoptosis of vascular endothelial cells. Method: Human umbilical vein endothelial cells (HUVECs) were pretreated with 0.1, 0.5, or 2.5 μg/mL of IGF-1 for 30 min before the addition of Ang II. Cell cycle redistribution and apoptosis were examined by flow cytometry. Expression of Ang II type 1 (AT 1 ) mRNA and cyclin E protein were determined by RT-PCR and Western blot, respectively. Results: Ang II (1 μmol/L) induced HUVECs arrested at G 0 /G 1 , enhanced the expression level of AT 1 mRNA in a time-dependent manner, reduced the enzymatic activity of nitric oxide synthase (NOS) and nitric oxide (NO) content as well as the expression level of cyclin E protein. However, IGF-1 enhanced NOS activity, NO content, and the expression level of cyclin E protein, and reduced the expression level of AT 1 mRNA. L-NAME significantly counteracted these effects of IGF-1. Conclusions: Our data suggests that IGF-1 can reverse vascular endothelial cells arrested at G 0 /G 1 and apoptosis induced by Ang II, which might be mediated via a NOS-NO signaling pathway and is likely associated with the expression levels of AT1 mRNA and cyclin E proteins.

  1. Cell cycle-specific UNG2 phosphorylations regulate protein turnover, activity and association with RPA

    DEFF Research Database (Denmark)

    Hagen, Lars; Kavli, Bodil; Sousa, Mirta M L

    2008-01-01

    -catalytic domain that confer distinct functional properties to UNG2. These are apparently generated by cyclin-dependent kinases through stepwise phosphorylation of S23, T60 and S64 in the cell cycle. Phosphorylation of S23 in late G1/early S confers increased association with replication protein A (RPA......) and replicating chromatin and markedly increases the catalytic turnover of UNG2. Conversely, progressive phosphorylation of T60 and S64 throughout S phase mediates reduced binding to RPA and flag UNG2 for breakdown in G2 by forming a cyclin E/c-myc-like phosphodegron. The enhanced catalytic turnover of UNG2 p-S23...

  2. Cell cycle arrest and gene expression profiling of testis in mice exposed to fluoride.

    Science.gov (United States)

    Su, Kai; Sun, Zilong; Niu, Ruiyan; Lei, Ying; Cheng, Jing; Wang, Jundong

    2017-05-01

    Exposure to fluoride results in low reproductive capacity; however, the mechanism underlying the impact of fluoride on male productive system still remains obscure. To assess the potential toxicity in testis of mice administrated with fluoride, global genome microarray and real-time PCR were performed to detect and identify the altered transcriptions. The results revealed that 763 differentially expressed genes were identified, including 330 up-regulated and 433 down-regulated genes, which were involved in spermatogenesis, apoptosis, DNA damage, DNA replication, and cell differentiation. Twelve differential expressed genes were selected to confirm the microarray results using real-time PCR, and the result kept the same tendency with that of microarray. Furthermore, compared with the control group, more apoptotic spermatogenic cells were observed in the fluoride group, and the spermatogonium were markedly increased in S phase and decreased in G2/M phase by fluoride. Our findings suggested global genome microarray provides an insight into the reproductive toxicity induced by fluoride, and several important biological clues for further investigations. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1558-1565, 2017. © 2016 Wiley Periodicals, Inc.

  3. Cell cycle regulator E2F4 is essential for the development of the ventral telencephalon.

    Science.gov (United States)

    Ruzhynsky, Vladimir A; McClellan, Kelly A; Vanderluit, Jacqueline L; Jeong, Yongsu; Furimsky, Marosh; Park, David S; Epstein, Douglas J; Wallace, Valerie A; Slack, Ruth S

    2007-05-30

    Early forebrain development is characterized by extensive proliferation of neural precursors coupled with complex structural transformations; however, little is known regarding the mechanisms by which these processes are integrated. Here, we show that deficiency of the cell cycle regulatory protein, E2F4, results in the loss of ventral telencephalic structures and impaired self-renewal of neural precursor cells. The mechanism underlying aberrant ventral patterning lies in a dramatic loss of Sonic hedgehog (Shh) expression specifically in this region. The E2F4-deficient phenotype can be recapitulated by interbreeding mice heterozygous for E2F4 with those lacking one allele of Shh, suggesting a genetic interaction between these pathways. Treatment of E2F4-deficient cells with a Hh agonist rescues stem cell self-renewal and cells expressing the homeodomain proteins that specify the ventral telencephalic structures. Finally, we show that E2F4 deficiency results in impaired activity of Shh forebrain-specific enhancers. In conclusion, these studies establish a novel requirement for the cell cycle regulatory protein, E2F4, in the development of the ventral telencephalon.

  4. Immunohistochemical study of the expression of cell cycle regulating proteins at different stages of bladder cancer

    DEFF Research Database (Denmark)

    Primdahl, Hanne; von der Maase, Hans; Sørensen, Flemming Brandt

    2002-01-01

    ; group 1, 23 patients with recurrent stage Ta (non-invasive) tumors; group 2, 22 patients presenting at their first admission with T2-4 (muscle invasive) tumors; group 3, 24 patients who experienced disease progression from Ta or T1 (invasive in connective tissue) to a higher stage......PURPOSE: The cell cycle is known to be deregulated in cancer. We therefore analyzed the expression of the cell cycle related proteins p21, p27, p16, Rb, and L-myc by immunohistochemical staining of bladder tumors.METHODS: The tissue material consisted of bladder tumors from three groups of patients......(kip1) ( P=0.03), Rb ( P=0.00002), and L-myc ( P=0.00000007) in muscle invasive tumors compared to noninvasive tumors. Tumors presenting as muscle invasive at first diagnosis had significantly lower levels of p16/CDKN2A ( P=0.01) when compared to muscle invasive tumors that followed Ta or T1 precursor...

  5. Deficiency of G1 regulators P53, P21Cip1 and/or pRb decreases hepatocyte sensitivity to TGFβ cell cycle arrest

    Directory of Open Access Journals (Sweden)

    Harrison David J

    2007-11-01

    Full Text Available Abstract Background TGFβ is critical to control hepatocyte proliferation by inducing G1-growth arrest through multiple pathways leading to inhibition of E2F transcription activity. The retinoblastoma protein pRb is a key controller of E2F activity and G1/S transition which can be inhibited in viral hepatitis. It is not known whether the impairment of pRb would alter the growth inhibitory potential of TGFβ in disease. We asked how Rb-deficiency would affect responses to TGFβ-induced cell cycle arrest. Results Primary hepatocytes isolated from Rb-floxed mice were infected with an adenovirus expressing CRE-recombinase to delete the Rb gene. In control cells treatment with TGFβ prevented cells to enter S phase via decreased cMYC activity, activation of P16INK4A and P21Cip and reduction of E2F activity. In Rb-null hepatocytes, cMYC activity decreased slightly but P16INK4A was not activated and the great majority of cells continued cycling. Rb is therefore central to TGFβ-induced cell cycle arrest in hepatocytes. However some Rb-null hepatocytes remained sensitive to TGFβ-induced cell cycle arrest. As these hepatocytes expressed very high levels of P21Cip1 and P53 we investigated whether these proteins regulate pRb-independent signaling to cell cycle arrest by evaluating the consequences of disruption of p53 and p21Cip1. Hepatocytes deficient in p53 or p21Cip1 showed diminished growth inhibition by TGFβ. Double deficiency had a similar impact showing that in cells containing functional pRb; P21Cip and P53 work through the same pathway to regulate G1/S in response to TGFβ. In Rb-deficient cells however, p53 but not p21Cip deficiency had an additive effect highlighting a pRb-independent-P53-dependent effector pathway of inhibition of E2F activity. Conclusion The present results show that otherwise genetically normal hepatocytes with disabled p53, p21Cip1 or Rb genes respond less well to the antiproliferative effects of TGFβ. As the function of

  6. Playing with the cell cycle to build the spinal cord.

    Science.gov (United States)

    Molina, Angie; Pituello, Fabienne

    2017-12-01

    A fundamental issue in nervous system development and homeostasis is to understand the mechanisms governing the balance between the maintenance of proliferating progenitors versus their differentiation into post-mitotic neurons. Accumulating data suggest that the cell cycle and core regulators of the cell cycle machinery play a major role in regulating this fine balance. Here, we focus on the interplay between the cell cycle and cellular and molecular events governing spinal cord development. We describe the existing links between the cell cycle and interkinetic nuclear migration (INM). We show how the different morphogens patterning the neural tube also regulate the cell cycle machinery to coordinate proliferation and patterning. We give examples of how cell cycle core regulators regulate transcriptionally, or post-transcriptionally, genes involved in controlling the maintenance versus the differentiation of neural progenitors. Finally, we describe the changes in cell cycle kinetics occurring during neural tube patterning and at the time of neuronal differentiation, and we discuss future research directions to better understand the role of the cell cycle in cell fate decisions. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. The negative cell cycle regulator, Tob (transducer of ErbB-2), is involved in motor skill learning

    International Nuclear Information System (INIS)

    Wang Xinming; Gao Xiang; Zhang Xuehan; Tu Yanyang; Jin Meilei; Zhao Guoping; Yu Lei; Jing Naihe; Li Baoming

    2006-01-01

    Tob (transducer of ErbB-2) is a negative cell cycle regulator with anti-proliferative activity in peripheral tissues. Our previous study identified Tob as a protein involved in hippocampus-dependent memory consolidation (M.L. Jin, X.M. Wang, Y.Y. Tu, X.H. Zhang, X. Gao, N. Guo, Z.Q. Xie, G.P. Zhao, N.H. Jing, B.M. Li, Y.Yu, The negative cell cycle regulator, Tob (Transducer of ErbB-2), is a multifunctional protein involved in hippocampus-dependent learning and memory, Neuroscience 131 (2005) 647-659). Here, we provide evidence that Tob in the central nervous system is engaged in acquisition of motor skill. Tob has a relatively high expression in the cerebellum. Tob expression is up-regulated in the cerebellum after rats receive training on a rotarod-running task. Rats infused with Tob antisense oligonucleotides into the 4th ventricle exhibit a severe deficit in running on a rotating rod or walking across a horizontally elevated beam

  8. Sequences within the 5' untranslated region regulate the levels of a kinetoplast DNA topoisomerase mRNA during the cell cycle.

    Science.gov (United States)

    Pasion, S G; Hines, J C; Ou, X; Mahmood, R; Ray, D S

    1996-12-01

    Gene expression in trypanosomatids appears to be regulated largely at the posttranscriptional level and involves maturation of mRNA precursors by trans splicing of a 39-nucleotide miniexon sequence to the 5' end of the mRNA and cleavage and polyadenylation at the 3' end of the mRNA. To initiate the identification of sequences involved in the periodic expression of DNA replication genes in trypanosomatids, we have mapped splice acceptor sites in the 5' flanking region of the TOP2 gene, which encodes the kinetoplast DNA topoisomerase, and have carried out deletion analysis of this region on a plasmid-encoded TOP2 gene. Block deletions within the 5' untranslated region (UTR) identified two regions (-608 to -388 and -387 to -186) responsible for periodic accumulation of the mRNA. Deletion of one or the other of these sequences had no effect on periodic expression of the mRNA, while deletion of both regions resulted in constitutive expression of the mRNA throughout the cell cycle. Subcloning of these sequences into the 5' UTR of a construct lacking both regions of the TOP2 5' UTR has shown that an octamer consensus sequence present in the 5' UTR of the TOP2, RPA1, and DHFR-TS mRNAs is required for normal cycling of the TOP2 mRNA. Mutation of the consensus octamer sequence in the TOP2 5' UTR in a plasmid construct containing only a single consensus octamer and that shows normal cycling of the plasmid-encoded TOP2 mRNA resulted in substantial reduction of the cycling of the mRNA level. These results imply a negative regulation of TOP2 mRNA during the cell cycle by a mechanism involving redundant elements containing one or more copies of a conserved octamer sequence within the 5' UTR of TOP2 mRNA.

  9. Perfusion of veins at arterial pressure increases the expression of KLF5 and cell cycle genes in smooth muscle cells

    International Nuclear Information System (INIS)

    Amirak, Emre; Zakkar, Mustafa; Evans, Paul C.; Kemp, Paul R.

    2010-01-01

    Vascular smooth muscle cell (VSMC) proliferation remains a major cause of veno-arterial graft failure. We hypothesised that exposure of venous SMCs to arterial pressure would increase KLF5 expression and that of cell cycle genes. Porcine jugular veins were perfused at arterial or venous pressure in the absence of growth factors. The KLF5, c-myc, cyclin-D and cyclin-E expression were elevated within 24 h of perfusion at arterial pressure but not at venous pressure. Arterial pressure also reduced the decline in SM-myosin heavy chain expression. These data suggest a role for KLF5 in initiating venous SMCs proliferation in response to arterial pressure.

  10. Glycogen synthase kinase 3 has a limited role in cell cycle regulation of cyclin D1 levels.

    Science.gov (United States)

    Yang, Ke; Guo, Yang; Stacey, William C; Harwalkar, Jyoti; Fretthold, Jonathan; Hitomi, Masahiro; Stacey, Dennis W

    2006-08-30

    The expression level of cyclin D1 plays a vital role in the control of proliferation. This protein is reported to be degraded following phosphorylation by glycogen synthase kinase 3 (GSK3) on Thr-286. We recently showed that phosphorylation of Thr-286 is responsible for a decline in cyclin D1 levels during S phase, an event required for efficient DNA synthesis. These studies were undertaken to test the possibility that phosphorylation by GSK3 is responsible for the S phase specific decline in cyclin D1 levels, and that this event is regulated by the phosphatidylinositol 3-kinase (PI3K)/AKT signaling pathway which controls GSK3. We found, however, that neither PI3K, AKT, GSK3, nor proliferative signaling activity in general is responsible for the S phase decline in cyclin D1 levels. In fact, the activity of these signaling kinases does not vary through the cell cycle of proliferating cells. Moreover, we found that GSK3 activity has little influence over cyclin D1 expression levels during any cell cycle phase. Inhibition of GSK3 activity by siRNA, LiCl, or other chemical inhibitors failed to influence cyclin D1 phosphorylation on Thr-286, even though LiCl efficiently blocked phosphorylation of beta-catenin, a known substrate of GSK3. Likewise, the expression of a constitutively active GSK3 mutant protein failed to influence cyclin D1 phosphorylation or total protein expression level. Because we were unable to identify any proliferative signaling molecule or pathway which is regulated through the cell cycle, or which is able to influence cyclin D1 levels, we conclude that the suppression of cyclin D1 levels during S phase is regulated by cell cycle position rather than signaling activity. We propose that this mechanism guarantees the decline in cyclin D1 levels during each S phase; and that in so doing it reduces the likelihood that simple over expression of cyclin D1 can lead to uncontrolled cell growth.

  11. Expression of the Long Intergenic Non-Protein Coding RNA 665 (LINC00665) Gene and the Cell Cycle in Hepatocellular Carcinoma Using The Cancer Genome Atlas, the Gene Expression Omnibus, and Quantitative Real-Time Polymerase Chain Reaction.

    Science.gov (United States)

    Wen, Dong-Yue; Lin, Peng; Pang, Yu-Yan; Chen, Gang; He, Yun; Dang, Yi-Wu; Yang, Hong

    2018-05-05

    BACKGROUND Long non-coding RNAs (lncRNAs) have a role in physiological and pathological processes, including cancer. The aim of this study was to investigate the expression of the long intergenic non-protein coding RNA 665 (LINC00665) gene and the cell cycle in hepatocellular carcinoma (HCC) using database analysis including The Cancer Genome Atlas (TCGA), the Gene Expression Omnibus (GEO), and quantitative real-time polymerase chain reaction (qPCR). MATERIAL AND METHODS Expression levels of LINC00665 were compared between human tissue samples of HCC and adjacent normal liver, clinicopathological correlations were made using TCGA and the GEO, and qPCR was performed to validate the findings. Other public databases were searched for other genes associated with LINC00665 expression, including The Atlas of Noncoding RNAs in Cancer (TANRIC), the Multi Experiment Matrix (MEM), Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and protein-protein interaction (PPI) networks. RESULTS Overexpression of LINC00665 in patients with HCC was significantly associated with gender, tumor grade, stage, and tumor cell type. Overexpression of LINC00665 in patients with HCC was significantly associated with overall survival (OS) (HR=1.47795%; CI: 1.046-2.086). Bioinformatics analysis identified 469 related genes and further analysis supported a hypothesis that LINC00665 regulates pathways in the cell cycle to facilitate the development and progression of HCC through ten identified core genes: CDK1, BUB1B, BUB1, PLK1, CCNB2, CCNB1, CDC20, ESPL1, MAD2L1, and CCNA2. CONCLUSIONS Overexpression of the lncRNA, LINC00665 may be involved in the regulation of cell cycle pathways in HCC through ten identified hub genes.

  12. Identification of genes involved in Ca2+ ionophore A23187-mediated apoptosis and demonstration of a high susceptibility for transcriptional repression of cell cycle genes in B lymphoblasts from a patient with Scott syndrome

    Directory of Open Access Journals (Sweden)

    Meyer Dominique

    2005-10-01

    Full Text Available Abstract Background In contrast to other agents able to induce apoptosis of cultured cells, Ca2+ ionophore A23187 was shown to elicit direct activation of intracellular signal(s. The phenotype of the cells derived from patients having the hemorrhagic disease Scott syndrome, is associated with an abnormally high proportion of apoptotic cells, both in basal culture medium and upon addition of low ionophore concentrations in long-term cultures. These features are presumably related to the mutation also responsible for the defective procoagulant plasma membrane remodeling. We analyzed the specific transcriptional re-programming induced by A23187 to get insights into the effect of this agent on gene expression and a defective gene regulation in Scott cells. Results The changes in gene expression upon 48 hours treatment with 200 nM A23187 were measured in Scott B lymphoblasts compared to B lymphoblasts derived from the patient's daughter or unrelated individuals using Affymetrix microarrays. In a similar manner in all of the B cell lines, results showed up-regulation of 55 genes, out of 12,000 represented sequences, involved in various pathways of the cell metabolism. In contrast, a group of 54 down-regulated genes, coding for histones and proteins involved in the cell cycle progression, was more significantly repressed in Scott B lymphoblasts than in the other cell lines. These data correlated with the alterations of the cell cycle phases in treated cells and suggested that the potent effect of A23187 in Scott B lymphoblasts may be the consequence of the underlying molecular defect. Conclusion The data illustrate that the ionophore A23187 exerts its pro-apoptotic effect by promoting a complex pattern of genetic changes. These results also suggest that a subset of genes participating in various steps of the cell cycle progress can be transcriptionally regulated in a coordinated fashion. Furthermore, this research brings a new insight into the defect

  13. Temporal mapping of CEBPA and CEBPB binding during liver regeneration reveals dynamic occupancy and specific regulatory codes for homeostatic and cell cycle gene batteries

    DEFF Research Database (Denmark)

    Jakobsen, Janus Schou; Waage, Johannes; Rapin, Nicolas

    2013-01-01

    quantified the genome-wide binding patterns of two key hepatocyte transcription factors, CEBPA and CEBPB (also known as C/EBPalpha and C/EBPbeta), at multiple time points during the highly dynamic process of liver regeneration elicited by partial hepatectomy in mouse. Combining these profiles with RNA...... polymerase II binding data, we find three temporal classes of transcription factor binding to be associated with distinct sets of regulated genes involved in the acute phase response, metabolic/homeostatic functions, or cell cycle progression. Moreover, we demonstrate a previously unrecognized early phase......IP experiments involving a panel of central transcription factors and/or by comparison to external ChIP-seq data. Our quantitative investigation not only provides in vivo evidence for the involvement of many new factors in liver regeneration but also points to similarities in the circuitries regulating self...

  14. Cell-cycle regulation of non-enzymatic functions of the Drosophila methyltransferase PR-Set7.

    Science.gov (United States)

    Zouaz, Amel; Fernando, Céline; Perez, Yannick; Sardet, Claude; Julien, Eric; Grimaud, Charlotte

    2018-04-06

    Tight cell-cycle regulation of the histone H4-K20 methyltransferase PR-Set7 is essential for the maintenance of genome integrity. In mammals, this mainly involves the interaction of PR-Set7 with the replication factor PCNA, which triggers the degradation of the enzyme by the CRL4CDT2 E3 ubiquitin ligase. PR-Set7 is also targeted by the SCFβ-TRCP ligase, but the role of this additional regulatory pathway remains unclear. Here, we show that Drosophila PR-Set7 undergoes a cell-cycle proteolytic regulation, independently of its interaction with PCNA. Instead, Slimb, the ortholog of β-TRCP, is specifically required for the degradation of the nuclear pool of PR-Set7 prior to S phase. Consequently, inactivation of Slimb leads to nuclear accumulation of PR-Set7, which triggers aberrant chromatin compaction and G1/S arrest. Strikingly, these phenotypes result from non-enzymatic PR-Set7 functions that prevent proper histone H4 acetylation independently of H4K20 methylation. Altogether, these results identify the Slimb-mediated PR-Set7 proteolysis as a new critical regulatory mechanism required for proper interphase chromatin organization at G1/S transition.

  15. Plant WEE1 kinase is cell cycle regulated and removed at mitosis via the 26S proteasome machinery

    Science.gov (United States)

    Cook, Gemma S.; Grønlund, Anne Lentz; Siciliano, Ilario; Spadafora, Natasha; Amini, Maryam; Herbert, Robert J.; Bitonti, M. Beatrice; Graumann, Katja; Francis, Dennis; Rogers, Hilary J.

    2013-01-01

    In yeasts and animals, premature entry into mitosis is prevented by the inhibitory phosphorylation of cyclin-dependent kinase (CDK) by WEE1 kinase, and, at mitosis, WEE1 protein is removed through the action of the 26S proteasome. Although in higher plants WEE1 function has been confirmed in the DNA replication checkpoint, Arabidopsis wee1 insertion mutants grow normally, and a role for the protein in the G2/M transition during an unperturbed plant cell cycle is yet to be confirmed. Here data are presented showing that the inhibitory effect of WEE1 on CDK activity in tobacco BY-2 cell cultures is cell cycle regulated independently of the DNA replication checkpoint: it is high during S-phase but drops as cells traverse G2 and enter mitosis. To investigate this mechanism further, a yeast two-hybrid screen was undertaken to identify proteins interacting with Arabidopsis WEE1. Three F-box proteins and a subunit of the proteasome complex were identified, and bimolecular fluorescence complementation confirmed an interaction between AtWEE1 and the F-box protein SKP1 INTERACTING PARTNER 1 (SKIP1). Furthermore, the AtWEE1–green fluorescent protein (GFP) signal in Arabidopsis primary roots treated with the proteasome inhibitor MG132 was significantly increased compared with mock-treated controls. Expression of AtWEE1–YFPC (C-terminal portion of yellow fluorescent protein) or AtWEE1 per se in tobacco BY-2 cells resulted in a premature increase in the mitotic index compared with controls, whereas co-expression of AtSKIP1–YFPN negated this effect. These data support a role for WEE1 in a normal plant cell cycle and its removal at mitosis via the 26S proteasome. PMID:23536609

  16. Multiparameter Cell Cycle Analysis.

    Science.gov (United States)

    Jacobberger, James W; Sramkoski, R Michael; Stefan, Tammy; Woost, Philip G

    2018-01-01

    Cell cycle cytometry and analysis are essential tools for studying cells of model organisms and natural populations (e.g., bone marrow). Methods have not changed much for many years. The simplest and most common protocol is DNA content analysis, which is extensively published and reviewed. The next most common protocol, 5-bromo-2-deoxyuridine S phase labeling detected by specific antibodies, is also well published and reviewed. More recently, S phase labeling using 5'-ethynyl-2'-deoxyuridine incorporation and a chemical reaction to label substituted DNA has been established as a basic, reliable protocol. Multiple antibody labeling to detect epitopes on cell cycle regulated proteins, which is what this chapter is about, is the most complex of these cytometric cell cycle assays, requiring knowledge of the chemistry of fixation, the biochemistry of antibody-antigen reactions, and spectral compensation. However, because this knowledge is relatively well presented methodologically in many papers and reviews, this chapter will present a minimal Methods section for one mammalian cell type and an extended Notes section, focusing on aspects that are problematic or not well described in the literature. Most of the presented work involves how to segment the data to produce a complete, progressive, and compartmentalized cell cycle analysis from early G1 to late mitosis (telophase). A more recent development, using fluorescent proteins fused with proteins or peptides that are degraded by ubiquitination during specific periods of the cell cycle, termed "Fucci" (fluorescent, ubiquitination-based cell cycle indicators) provide an analysis similar in concept to multiple antibody labeling, except in this case cells can be analyzed while living and transgenic organisms can be created to perform cell cycle analysis ex or in vivo (Sakaue-Sawano et al., Cell 132:487-498, 2007). This technology will not be discussed.

  17. Autophagic flux is highly active in early mitosis and differentially regulated throughout the cell cycle.

    Science.gov (United States)

    Li, Zhiyuan; Ji, Xinmiao; Wang, Dongmei; Liu, Juanjuan; Zhang, Xin

    2016-06-28

    Mitosis is a fast process that involves dramatic cellular remodeling and has a high energy demand. Whether autophagy is active or inactive during the early stages of mitosis in a naturally dividing cell is still debated. Here we aimed to use multiple assays to resolve this apparent discrepancy. Although the LC3 puncta number was reduced in mitosis, the four different cell lines we tested all have active autophagic flux in both interphase and mitosis. In addition, the autophagic flux was highly active in nocodazole-induced, double-thymidine synchronization released as well as naturally occurring mitosis in HeLa cells. Multiple autophagy proteins are upregulated in mitosis and the increased Beclin-1 level likely contributes to the active autophagic flux in early mitosis. It is interesting that although the autophagic flux is active throughout the cell cycle, early mitosis and S phase have relatively higher autophagic flux than G1 and late G2 phases, which might be helpful to degrade the damaged organelles and provide energy during S phase and mitosis.

  18. Cell Cycle Regulation and Apoptotic Responses of the Embryonic Chick Retina by Ionizing Radiation.

    Directory of Open Access Journals (Sweden)

    Margot Mayer

    Full Text Available Ionizing radiation (IR exerts deleterious effects on the developing brain, since proliferative neuronal progenitor cells are highly sensitive to IR-induced DNA damage. Assuming a radiation response that is comparable to mammals, the chick embryo would represent a lower vertebrate model system that allows analysis of the mechanisms underlying this sensitivity, thereby contributing to the reduction, refinement and replacement of animal experiments. Thus, this study aimed to elucidate the radiation response of the embryonic chick retina in three selected embryonic stages. Our studies reveal a lack in the radiation-induced activation of a G1/S checkpoint, but rapid abrogation of G2/M progression after IR in retinal progenitors throughout development. Unlike cell cycle control, radiation-induced apoptosis (RIA showed strong variations between its extent, dose dependency and temporal occurrence. Whereas the general sensitivity towards RIA declined with ongoing differentiation, its dose dependency constantly increased with age. For all embryonic stages RIA occurred during comparable periods after irradiation, but in older animals its maximum shifted towards earlier post-irradiation time points. In summary, our results are in good agreement with data from the developing rodent retina, strengthening the suitability of the chick embryo for the analysis of the radiation response in the developing central nervous system.

  19. In Vitro Effects of Bromoalkyl Phenytoin Derivatives on Regulated Death, Cell Cycle and Ultrastructure of Leukemia Cells.

    Science.gov (United States)

    Śladowska, Katarzyna; Opydo-Chanek, Małgorzata; Król, Teodora; Trybus, Wojciech; Trybus, Ewa; Kopacz-Bednarska, Anna; Handzlik, Jadwiga; Kieć-Kononowicz, Katarzyna; Mazur, Lidia

    2017-11-01

    To search for new antileukemic agents, the chemical structure of phenytoin was modified. A possible cytotoxic activity of three bromoalkyl phenytoin analogs, methyl 2-(1-(3-bromopropyl)-2,4-dioxo-5,5-diphenylimidazolidin-3-yl) propanoate (PH2), 1-(3-bromopropyl)-3-methyl-5,5-diphenylimidazolidine-2,4-dione (PH3) and 1-(4-bromobutyl)-3-methyl-5,5-diphenylimidazolidine-2,4-dione (PH4) on regulated cell death, the cell cycle and cell ultrastructure was assessed. The experiments were performed in vitro on HL-60 and U937 cells, using flow cytometry and electron microscopy methods. Application of PH2, PH3, and PH4 resulted in cell surface exposure of phosphatidylserine and plasma membrane impairment, caspase-8, -9, and -3/7 activation, dissipation of mitochondrial membrane potential, DNA breakage, cell-cycle disturbance and cell ultrastructural changes. In general, PH3 appeared to be the most active against the leukemia cells, and all bromoalkyl hydantoins, PH2-PH4, were more active in HL-60 cells than in U937 cells. The antileukemic activity of the bromoalkyl phenytoin analogs depended on the combination of N-hydantoin substituents and the human cell line used. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

  20. Herpes simplex virus 1 regulatory protein ICP22 interacts with a new cell cycle-regulated factor and accumulates in a cell cycle-dependent fashion in infected cells.

    Science.gov (United States)

    Bruni, R; Roizman, B

    1998-11-01

    The herpes simplex virus 1 infected cell protein 22 (ICP22), the product of the alpha22 gene, is a nucleotidylylated and phosphorylated nuclear protein with properties of a transcriptional factor required for the expression of a subset of viral genes. Here, we report the following. (i) ICP22 interacts with a previously unknown cellular factor designated p78 in the yeast two-hybrid system. The p78 cDNA encodes a polypeptide with a distribution of leucines reminiscent of a leucine zipper. (ii) In uninfected and infected cells, antibody to p78 reacts with two major bands with an apparent Mr of 78,000 and two minor bands with apparent Mrs of 62, 000 and 55,000. (ii) p78 also interacts with ICP22 in vitro. (iii) In uninfected cells, p78 was dispersed largely in the nucleoplasm in HeLa cells and in the nucleoplasm and cytoplasm in HEp-2 cells. After infection, p78 formed large dense bodies which did not colocalize with the viral regulatory protein ICP0. (iv) Accumulation of p78 was cell cycle dependent, being highest very early in S phase. (v) The accumulation of ICP22 in synchronized cells was highest in early S phase, in contrast to the accumulation of another protein, ICP27, which was relatively independent of the cell cycle. (vi) In the course of the cell cycle, ICP22 was transiently modified in an aberrant fashion, and this modification coincided with expression of p78. The results suggest that ICP22 interacts with and may be stabilized by cell cycle-dependent proteins.

  1. miR-24 inhibits cell proliferation by suppressing expression of E2F2, MYC and other cell cycle regulatory genes by binding to “seedless” 3′UTR microRNA recognition elements

    Science.gov (United States)

    Lal, Ashish; Navarro, Francisco; Maher, Christopher; Maliszewski, Laura E.; Yan, Nan; O'Day, Elizabeth; Chowdhury, Dipanjan; Dykxhoorn, Derek M.; Tsai, Perry; Hofman, Oliver; Becker, Kevin G.; Gorospe, Myriam; Hide, Winston; Lieberman, Judy

    2009-01-01

    Summary miR-24, up-regulated during terminal differentiation of multiple lineages, inhibits cell cycle progression. Antagonizing miR-24 restores post-mitotic cell proliferation and enhances fibroblast proliferation, while over-expressing miR-24 increases the G1 compartment. The 248 mRNAs down-regulated upon miR-24 over-expression are highly enriched for DNA repair and cell cycle regulatory genes that form a direct interaction network with prominent nodes at genes that enhance (MYC, E2F2, CCNB1, CDC2) or inhibit (p27Kip1, VHL) cell cycle progression. miR-24 directly regulates MYC and E2F2 and some genes they transactivate. Enhanced proliferation from antagonizing miR-24 is abrogated by knocking down E2F2, but not MYC, and cell proliferation, inhibited by miR-24 over-expression, is rescued by miR-24-insensitive E2F2. Therefore, E2F2 is a critical miR-24 target. The E2F2 3′UTR lacks a predicted miR-24 recognition element. In fact, miR-24 regulates expression of E2F2, MYC, AURKB, CCNA2, CDC2, CDK4 and FEN1 by recognizing seedless, but highly complementary, sequences. PMID:19748357

  2. Altered cell cycle-related gene expression in brain and lymphocytes from a transgenic mouse model of Alzheimer's disease [amyloid precursor protein/presenilin 1 (PS1)].

    Science.gov (United States)

    Esteras, Noemí; Bartolomé, Fernando; Alquézar, Carolina; Antequera, Desireé; Muñoz, Úrsula; Carro, Eva; Martín-Requero, Ángeles

    2012-09-01

    Cumulative evidence indicates that aberrant re-expression of many cell cycle-related proteins and inappropriate neuronal cell cycle control are critical events in Alzheimer's disease (AD) pathogenesis. Evidence of cell cycle activation in post-mitotic neurons has also been observed in murine models of AD, despite the fact that most of these mice do not show massive loss of neuronal bodies. Dysfunction of the cell cycle appears to affect cells other than neurons, as peripheral cells, such as lymphocytes and fibroblasts from patients with AD, show an altered response to mitogenic stimulation. We sought to determine whether cell cycle disturbances are present simultaneously in both brain and peripheral cells from the amyloid precursor protein (APP)/presenilin 1 (PS1) mouse model of AD, in order to validate the use of peripheral cells from patients not only to study cell cycle abnormalities as a pathogenic feature of AD, but also as a means to test novel therapeutic approaches. By using cell cycle pathway-specific RT(2)Profiler™ PCR Arrays, we detected changes in a number of cell cycle-related genes in brain as well as in lymphocytes from APP/PS1 mice. Moreover, we found enhanced 5'-bromo-2'-deoxyuridine incorporation into DNA in lymphocytes from APP/PS1 mice, and increased expression of the cell proliferation marker proliferating cell nuclear antigen (PCNA), and the cyclin-dependent kinase (CDK) inhibitor Cdkn2a, as detected by immunohistochemistry in cortical neurons of the APP/PS1 mice. Taken together, the cell cycle-related changes in brain and blood cells reported here support the mitosis failure hypothesis in AD and validate the use of peripheral cells as surrogate tissue to study the molecular basis of AD pathogenesis. © 2012 The Authors. European Journal of Neuroscience © 2012 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.

  3. Wounding coordinately induces cell wall protein, cell cycle and pectin methyl esterase genes involved in tuber closing layer and wound periderm development.

    Science.gov (United States)

    Neubauer, Jonathan D; Lulai, Edward C; Thompson, Asunta L; Suttle, Jeffrey C; Bolton, Melvin D

    2012-04-15

    Little is known about the coordinate induction of genes that may be involved in agriculturally important wound-healing events. In this study, wound-healing events were determined together with wound-induced expression profiles of selected cell cycle, cell wall protein, and pectin methyl esterase genes using two diverse potato genotypes and two harvests (NDTX4271-5R and Russet Burbank tubers; 2008 and 2009 harvests). By 5 d after wounding, the closing layer and a nascent phellogen had formed. Phellogen cell divisions generated phellem layers until cessation of cell division at 28 d after wounding for both genotypes and harvests. Cell cycle genes encoding epidermal growth factor binding protein (StEBP), cyclin-dependent kinase B (StCDKB) and cyclin-dependent kinase regulatory subunit (StCKS1At) were induced by 1 d after wounding; these expressions coordinated with related phellogen formation and the induction and cessation of phellem cell formation. Genes encoding the structural cell wall proteins extensin (StExt1) and extensin-like (StExtlk) were dramatically up-regulated by 1-5 d after wounding, suggesting involvement with closing layer and later phellem cell layer formation. Wounding up-regulated pectin methyl esterase genes (StPME and StPrePME); StPME expression increased during closing layer and phellem cell formation, whereas maximum expression of StPrePME occurred at 5-14 d after wounding, implicating involvement in later modifications for closing layer and phellem cell formation. The coordinate induction and expression profile of StTLRP, a gene encoding a cell wall strengthening "tyrosine-and lysine-rich protein," suggested a role in the formation of the closing layer followed by phellem cell generation and maturation. Collectively, the genes monitored were wound-inducible and their expression profiles markedly coordinated with closing layer formation and the index for phellogen layer meristematic activity during wound periderm development; results were more

  4. Cell cycle arrest induced by radiation

    International Nuclear Information System (INIS)

    Okaichi, Yasuo; Matsumoto, Hideki; Ohnishi, Takeo

    1994-01-01

    It is known that various chemical reactions, such as cell cycle arrest, DNA repair and cell killing, can occur within the cells when exposed to ionizing radiation and ultraviolet radiation. Thus protein dynamics involved in such chemical reactions has received considerable attention. In this article, cell cycle regulation is first discussed in terms of the G2/M-phase and the G1/S-phase. Then, radiation-induced cell cycle arrest is reviewed. Cell cycle regulation mechanism involved in the G2 arrest, which is well known to occur when exposed to radiation, has recently been investigated using yeasts. In addition, recent study has yielded a noticeable finding that the G1 arrest can occur with intracellular accumulation of p53 product following ionization radiation. p53 is also shown to play an extremely important role in both DNA repair and cell killing due to DNA damage. Studies on the role of genes in protein groups induced by radiation will hold promise for the elucidation of cell cycle mechanism. (N.K.) 57 refs

  5. The BTB and CNC homology 1 (BACH1) target genes are involved in the oxidative stress response and in control of the cell cycle.

    Science.gov (United States)

    Warnatz, Hans-Jörg; Schmidt, Dominic; Manke, Thomas; Piccini, Ilaria; Sultan, Marc; Borodina, Tatiana; Balzereit, Daniela; Wruck, Wasco; Soldatov, Alexey; Vingron, Martin; Lehrach, Hans; Yaspo, Marie-Laure

    2011-07-01

    The regulation of gene expression in response to environmental signals and metabolic imbalances is a key step in maintaining cellular homeostasis. BTB and CNC homology 1 (BACH1) is a heme-binding transcription factor repressing the transcription from a subset of MAF recognition elements at low intracellular heme levels. Upon heme binding, BACH1 is released from the MAF recognition elements, resulting in increased expression of antioxidant response genes. To systematically address the gene regulatory networks involving BACH1, we combined chromatin immunoprecipitation sequencing analysis of BACH1 target genes in HEK 293 cells with knockdown of BACH1 using three independent types of small interfering RNAs followed by transcriptome profiling using microarrays. The 59 BACH1 target genes identified by chromatin immunoprecipitation sequencing were found highly enriched in genes showing expression changes after BACH1 knockdown, demonstrating the impact of BACH1 repression on transcription. In addition to known and new BACH1 targets involved in heme degradation (HMOX1, FTL, FTH1, ME1, and SLC48A1) and redox regulation (GCLC, GCLM, and SLC7A11), we also discovered BACH1 target genes affecting cell cycle and apoptosis pathways (ITPR2, CALM1, SQSTM1, TFE3, EWSR1, CDK6, BCL2L11, and MAFG) as well as subcellular transport processes (CLSTN1, PSAP, MAPT, and vault RNA). The newly identified impact of BACH1 on genes involved in neurodegenerative processes and proliferation provides an interesting basis for future dissection of BACH1-mediated gene repression in neurodegeneration and virus-induced cancerogenesis.

  6. Human T-lymphotropic virus type-1 p30 alters cell cycle G2 regulation of T lymphocytes to enhance cell survival

    Directory of Open Access Journals (Sweden)

    Silverman Lee

    2007-07-01

    Full Text Available Abstract Background Human T-lymphotropic virus type-1 (HTLV-1 causes adult T-cell leukemia/lymphoma and is linked to a number of lymphocyte-mediated disorders. HTLV-1 contains both regulatory and accessory genes in four pX open reading frames. pX ORF-II encodes two proteins, p13 and p30, whose roles are still being defined in the virus life cycle and in HTLV-1 virus-host cell interactions. Proviral clones of HTLV-1 with pX ORF-II mutations diminish the ability of the virus to maintain viral loads in vivo. p30 expressed exogenously differentially modulates CREB and Tax-responsive element-mediated transcription through its interaction with CREB-binding protein/p300 and while acting as a repressor of many genes including Tax, in part by blocking tax/rex RNA nuclear export, selectively enhances key gene pathways involved in T-cell signaling/activation. Results Herein, we analyzed the role of p30 in cell cycle regulation. Jurkat T-cells transduced with a p30 expressing lentivirus vector accumulated in the G2-M phase of cell cycle. We then analyzed key proteins involved in G2-M checkpoint activation. p30 expression in Jurkat T-cells resulted in an increase in phosphorylation at serine 216 of nuclear cell division cycle 25C (Cdc25C, had enhanced checkpoint kinase 1 (Chk1 serine 345 phosphorylation, reduced expression of polo-like kinase 1 (PLK1, diminished phosphorylation of PLK1 at tyrosine 210 and reduced phosphorylation of Cdc25C at serine 198. Finally, primary human lymphocyte derived cell lines immortalized by a HTLV-1 proviral clone defective in p30 expression were more susceptible to camptothecin induced apoptosis. Collectively these data are consistent with a cell survival role of p30 against genotoxic insults to HTLV-1 infected lymphocytes. Conclusion Collectively, our data are the first to indicate that HTLV-1 p30 expression results in activation of the G2-M cell cycle checkpoint, events that would promote early viral spread and T

  7. Proliferating cell nuclear antigen (PCNA)-associated KIAA0101/PAF15 protein is a cell cycle-regulated anaphase-promoting complex/cyclosome substrate.

    Science.gov (United States)

    Emanuele, Michael J; Ciccia, Alberto; Elia, Andrew E H; Elledge, Stephen J

    2011-06-14

    The anaphase-promoting complex/cyclosome (APC/C) is a cell cycle-regulated E3 ubiquitin ligase that controls the degradation of substrate proteins at mitotic exit and throughout the G1 phase. We have identified an APC/C substrate and cell cycle-regulated protein, KIAA0101/PAF15. PAF15 protein levels peak in the G2/M phase of the cell cycle and drop rapidly at mitotic exit in an APC/C- and KEN-box-dependent fashion. PAF15 associates with proliferating cell nuclear antigen (PCNA), and depletion of PAF15 decreases the number of cells in S phase, suggesting a role for it in cell cycle regulation. Following irradiation, PAF15 colocalized with γH2AX foci at sites of DNA damage through its interaction with PCNA. Finally, PAF15 depletion led to an increase in homologous recombination-mediated DNA repair, and overexpression caused sensitivity to UV-induced DNA damage. We conclude that PAF15 is an APC/C-regulated protein involved in both cell cycle progression and the DNA damage response.

  8. DNMT1 is associated with cell cycle and DNA replication gene sets in diffuse large B-cell lymphoma.

    Science.gov (United States)

    Loo, Suet Kee; Ab Hamid, Suzina Sheikh; Musa, Mustaffa; Wong, Kah Keng

    2018-01-01

    Dysregulation of DNA (cytosine-5)-methyltransferase 1 (DNMT1) is associated with the pathogenesis of various types of cancer. It has been previously shown that DNMT1 is frequently expressed in diffuse large B-cell lymphoma (DLBCL), however its functions remain to be elucidated in the disease. In this study, we gene expression profiled (GEP) shRNA targeting DNMT1(shDNMT1)-treated germinal center B-cell-like DLBCL (GCB-DLBCL)-derived cell line (i.e. HT) compared with non-silencing shRNA (control shRNA)-treated HT cells. Independent gene set enrichment analysis (GSEA) performed using GEPs of shRNA-treated HT cells and primary GCB-DLBCL cases derived from two publicly-available datasets (i.e. GSE10846 and GSE31312) produced three separate lists of enriched gene sets for each gene sets collection from Molecular Signatures Database (MSigDB). Subsequent Venn analysis identified 268, 145 and six consensus gene sets from analyzing gene sets in C2 collection (curated gene sets), C5 sub-collection [gene sets from gene ontology (GO) biological process ontology] and Hallmark collection, respectively to be enriched in positive correlation with DNMT1 expression profiles in shRNA-treated HT cells, GSE10846 and GSE31312 datasets [false discovery rate (FDR) 0.8) with DNMT1 expression and significantly downregulated (log fold-change <-1.35; p<0.05) following DNMT1 silencing in HT cells. These results suggest the involvement of DNMT1 in the activation of cell cycle and DNA replication in DLBCL cells. Copyright © 2017 Elsevier GmbH. All rights reserved.

  9. Activation of the ribosomal RNA genes late in the third cell cycle of porcine embryos

    DEFF Research Database (Denmark)

    Viuff, Dorthe; Greve, Torben; Holm, Peter

    2002-01-01

    ; there was no silver staining at the sites of the rRNA genes and nucleolus precursor bodies. From 30 hpc onwards, most 4-cell embryos had medium size to large clusters of FITC-labeled areas colocalized with silver staining of rRNA gene clusters and fibrillogranular nucleoli. These observations indicate that r...

  10. Regulation of the Chlamydomonas Cell Cycle by a Stable, Chromatin-Associated Retinoblastoma Tumor Suppressor Complex

    Czech Academy of Sciences Publication Activity Database

    Olson, B. J. S. C.; Oberholzer, M.; Li, Y.; Zones, J. M.; Kohli, H. S.; Bišová, Kateřina; Fang, S.; Ch.; Meisenhelder, J.; Hunter, T.; Umen, J. G.

    2010-01-01

    Roč. 22, č. 10 (2010), s. 3331-3347 ISSN 1040-4651 Institutional research plan: CEZ:AV0Z50200510 Keywords : GENOME-WIDE ANALYSIS * TRANSCRIPTION FACTOR * GENE-PRODUCT Subject RIV: EE - Microbiology, Virology Impact factor: 9.396, year: 2010

  11. Regulation of DNA synthesis and the cell cycle in human prostate cancer cells and lymphocytes by ovine uterine serpin

    Directory of Open Access Journals (Sweden)

    Hansen Peter J

    2008-01-01

    Full Text Available Abstract Background Uterine serpins are members of the serine proteinase inhibitor superfamily. Like some other serpins, these proteins do not appear to be functional proteinase inhibitors. The most studied member of the group, ovine uterine serpin (OvUS, inhibits proliferation of several cell types including activated lymphocytes, bovine preimplantation embryos, and cell lines for lymphoma, canine primary osteosarcoma and human prostate cancer (PC-3 cells. The goal for the present study was to evaluate the mechanism by which OvUS inhibits cell proliferation. In particular, it was tested whether inhibition of DNA synthesis in PC-3 cells involves cytotoxic actions of OvUS or the induction of apoptosis. The effect of OvUS in the production of the autocrine and angiogenic cytokine interleukin (IL-8 by PC-3 cells was also determined. Finally, it was tested whether OvUS blocks specific steps in the cell cycle using both PC-3 cells and lymphocytes. Results Recombinant OvUS blocked proliferation of PC-3 cells at concentrations as low as 8 μg/ml as determined by measurements of [3H]thymidine incorporation or ATP content per well. Treatment of PC-3 cells with OvUS did not cause cytotoxicity or apoptosis or alter interleukin-8 secretion into medium. Results from flow cytometry experiments showed that OvUS blocked the entry of PC-3 cells into S phase and the exit from G2/M phase. In addition, OvUS blocked entry of lymphocytes into S phase following activation of proliferation with phytohemagglutinin. Conclusion Results indicate that OvUS acts to block cell proliferation through disruption of the cell cycle dynamics rather than induction of cytotoxicity or apoptosis. The finding that OvUS can regulate cell proliferation makes this one of only a few serpins that function to inhibit cell growth.

  12. Polycomb proteins control proliferation and transformation independently of cell cycle checkpoints by regulating DNA replication

    DEFF Research Database (Denmark)

    Piunti, Andrea; Rossi, Alessandra; Cerutti, Aurora

    2014-01-01

    The ability of PRC1 and PRC2 to promote proliferation is a main feature that links polycomb (PcG) activity to cancer. PcGs silence the expression of the tumour suppressor locus Ink4a/Arf, whose products positively regulate pRb and p53 functions. Enhanced PcG activity is a frequent feature of human...

  13. Cell cycle and aging, morphogenesis, and response to stimuli genes are individualized biomarkers of glioblastoma progression and survival

    Directory of Open Access Journals (Sweden)

    Southey Bruce R

    2011-06-01

    . Biological processes associated glioblastoma survival included morphogenesis, cell cycle, aging, response to stimuli, and programmed cell death. Conclusions Known biomarkers of glioblastoma survival were confirmed, and new general and clinical-dependent gene profiles were uncovered. The comparison of biomarkers across glioblastoma phases and functional analyses offered insights into the role of genes. These findings support the development of more accurate and personalized prognostic tools and gene-based therapies that improve the survival and quality of life of individuals afflicted by glioblastoma multiforme.

  14. Cell Cycle and Apoptosis Regulatory Protein (CARP)-1 is Expressed inOsteoblasts and Regulated by PTH

    International Nuclear Information System (INIS)

    Sharma, Sonali; Mahalingam, Chandrika D.; Das, Varsha; Jamal, Shazia; Levi, Edi; Rishi, Arun K.; Datta, Nabanita S.

    2013-01-01

    Highlights: •CARP-1 is identified for the first time in bone cells. •PTH downregulates CARP-1 expression in differentiated osteoblasts. •PTH displaces CARP-1 from nucleus to the cytoplasm in differentiated osteoblasts. •Downregulation of CARP-1 by PTH involves PKA, PKC and P-p38 MAPK pathways. -- Abstract: Bone mass is dependent on osteoblast proliferation, differentiation and life-span of osteoblasts. Parathyroid hormone (PTH) controls osteoblast cell cycle regulatory proteins and suppresses mature osteoblasts apoptosis. Intermittent administration of PTH increases bone mass but the mechanism of action are complex and incompletely understood. Cell Cycle and Apoptosis Regulatory Protein (CARP)-1 (aka CCAR1) is a novel transducer of signaling by diverse agents including cell growth and differentiation factors. To gain further insight into the molecular mechanism, we investigated involvement of CARP-1 in PTH signaling in osteoblasts. Immunostaining studies revealed presence of CARP-1 in osteoblasts and osteocytes, while a minimal to absent levels were noted in the chondrocytes of femora from 10 to 12-week old mice. Treatment of 7-day differentiated MC3T3-E1 clone-4 (MC-4) mouse osteoblastic cells and primary calvarial osteoblasts with PTH for 30 min to 5 h followed by Western blot analysis showed 2- to 3-fold down-regulation of CARP-1 protein expression in a dose- and time-dependent manner compared to the respective vehicle treated control cells. H-89, a Protein Kinase A (PKA) inhibitor, suppressed PTH action on CARP-1 protein expression indicating PKA-dependent mechanism. PMA, a Protein Kinase C (PKC) agonist, mimicked PTH action, and the PKC inhibitor, GF109203X, partially blocked PTH-dependent downregulation of CARP-1, implying involvement of PKC. U0126, a Mitogen-Activated Protein Kinase (MAPK) Kinase (MEK) inhibitor, failed to interfere with CARP-1 suppression by PTH. In contrast, SB203580, p38 inhibitor, attenuated PTH down-regulation of CARP-1

  15. Cell Cycle and Apoptosis Regulatory Protein (CARP)-1 is Expressed inOsteoblasts and Regulated by PTH

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Sonali; Mahalingam, Chandrika D.; Das, Varsha [Department of Internal Medicine/Endocrinology, Wayne State University School of Medicine, Detroit, MI 48201 (United States); Jamal, Shazia [Department of Oncology, Wayne State University School of Medicine, Detroit, MI 48201 (United States); Levi, Edi [Department of Oncology, Wayne State University School of Medicine, Detroit, MI 48201 (United States); Department of Pathology, Wayne State University School of Medicine, Detroit, MI 48201 (United States); Rishi, Arun K. [Department of Oncology, Wayne State University School of Medicine, Detroit, MI 48201 (United States); Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI 48201 (United States); VA Medical Center, Wayne State University School of Medicine, Detroit, MI 48201 (United States); Datta, Nabanita S., E-mail: ndatta@med.wayne.edu [Department of Internal Medicine/Endocrinology, Wayne State University School of Medicine, Detroit, MI 48201 (United States); Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI 48201 (United States); Cardiovascular Research Institute, Wayne State University School of Medicine, Detroit, MI 48201 (United States)

    2013-07-12

    Highlights: •CARP-1 is identified for the first time in bone cells. •PTH downregulates CARP-1 expression in differentiated osteoblasts. •PTH displaces CARP-1 from nucleus to the cytoplasm in differentiated osteoblasts. •Downregulation of CARP-1 by PTH involves PKA, PKC and P-p38 MAPK pathways. -- Abstract: Bone mass is dependent on osteoblast proliferation, differentiation and life-span of osteoblasts. Parathyroid hormone (PTH) controls osteoblast cell cycle regulatory proteins and suppresses mature osteoblasts apoptosis. Intermittent administration of PTH increases bone mass but the mechanism of action are complex and incompletely understood. Cell Cycle and Apoptosis Regulatory Protein (CARP)-1 (aka CCAR1) is a novel transducer of signaling by diverse agents including cell growth and differentiation factors. To gain further insight into the molecular mechanism, we investigated involvement of CARP-1 in PTH signaling in osteoblasts. Immunostaining studies revealed presence of CARP-1 in osteoblasts and osteocytes, while a minimal to absent levels were noted in the chondrocytes of femora from 10 to 12-week old mice. Treatment of 7-day differentiated MC3T3-E1 clone-4 (MC-4) mouse osteoblastic cells and primary calvarial osteoblasts with PTH for 30 min to 5 h followed by Western blot analysis showed 2- to 3-fold down-regulation of CARP-1 protein expression in a dose- and time-dependent manner compared to the respective vehicle treated control cells. H-89, a Protein Kinase A (PKA) inhibitor, suppressed PTH action on CARP-1 protein expression indicating PKA-dependent mechanism. PMA, a Protein Kinase C (PKC) agonist, mimicked PTH action, and the PKC inhibitor, GF109203X, partially blocked PTH-dependent downregulation of CARP-1, implying involvement of PKC. U0126, a Mitogen-Activated Protein Kinase (MAPK) Kinase (MEK) inhibitor, failed to interfere with CARP-1 suppression by PTH. In contrast, SB203580, p38 inhibitor, attenuated PTH down-regulation of CARP-1

  16. Progesterone receptor blockade in human breast cancer cells decreases cell cycle progression through G2/M by repressing G2/M genes.

    Science.gov (United States)

    Clare, Susan E; Gupta, Akash; Choi, MiRan; Ranjan, Manish; Lee, Oukseub; Wang, Jun; Ivancic, David Z; Kim, J Julie; Khan, Seema A

    2016-05-23

    The synthesis of specific, potent progesterone antagonists adds potential agents to the breast cancer prevention and treatment armamentarium. The identification of individuals who will benefit from these agents will be a critical factor for their clinical success. We utilized telapristone acetate (TPA; CDB-4124) to understand the effects of progesterone receptor (PR) blockade on proliferation, apoptosis, promoter binding, cell cycle progression, and gene expression. We then identified a set of genes that overlap with human breast luteal-phase expressed genes and signify progesterone activity in both normal breast cells and breast cancer cell lines. TPA administration to T47D cells results in a 30 % decrease in cell number at 24 h, which is maintained over 72 h only in the presence of estradiol. Blockade of progesterone signaling by TPA for 24 h results in fewer cells in G2/M, attributable to decreased expression of genes that facilitate the G2/M transition. Gene expression data suggest that TPA affects several mechanisms that progesterone utilizes to control gene expression, including specific post-translational modifications, and nucleosomal organization and higher order chromatin structure, which regulate access of PR to its DNA binding sites. By comparing genes induced by the progestin R5020 in T47D cells with those increased in the luteal-phase normal breast, we have identified a set of genes that predict functional progesterone signaling in tissue. These data will facilitate an understanding of the ways in which drugs such as TPA may be utilized for the prevention, and possibly the therapy, of human breast cancer.

  17. Progesterone receptor blockade in human breast cancer cells decreases cell cycle progression through G2/M by repressing G2/M genes

    International Nuclear Information System (INIS)

    Clare, Susan E.; Gupta, Akash; Choi, MiRan; Ranjan, Manish; Lee, Oukseub; Wang, Jun; Ivancic, David Z.; Kim, J. Julie; Khan, Seema A.

    2016-01-01

    The synthesis of specific, potent progesterone antagonists adds potential agents to the breast cancer prevention and treatment armamentarium. The identification of individuals who will benefit from these agents will be a critical factor for their clinical success. We utilized telapristone acetate (TPA; CDB-4124) to understand the effects of progesterone receptor (PR) blockade on proliferation, apoptosis, promoter binding, cell cycle progression, and gene expression. We then identified a set of genes that overlap with human breast luteal-phase expressed genes and signify progesterone activity in both normal breast cells and breast cancer cell lines. TPA administration to T47D cells results in a 30 % decrease in cell number at 24 h, which is maintained over 72 h only in the presence of estradiol. Blockade of progesterone signaling by TPA for 24 h results in fewer cells in G2/M, attributable to decreased expression of genes that facilitate the G2/M transition. Gene expression data suggest that TPA affects several mechanisms that progesterone utilizes to control gene expression, including specific post-translational modifications, and nucleosomal organization and higher order chromatin structure, which regulate access of PR to its DNA binding sites. By comparing genes induced by the progestin R5020 in T47D cells with those increased in the luteal-phase normal breast, we have identified a set of genes that predict functional progesterone signaling in tissue. These data will facilitate an understanding of the ways in which drugs such as TPA may be utilized for the prevention, and possibly the therapy, of human breast cancer. The online version of this article (doi:10.1186/s12885-016-2355-5) contains supplementary material, which is available to authorized users

  18. Cdt1 revisited: complex and tight regulation during the cell cycle and consequences of deregulation in mammalian cells

    Directory of Open Access Journals (Sweden)

    Fujita Masatoshi

    2006-10-01

    Full Text Available Abstract In eukaryotic cells, replication of genomic DNA initiates from multiple replication origins distributed on multiple chromosomes. To ensure that each origin is activated precisely only once during each S phase, a system has evolved which features periodic assembly and disassembly of essential pre-replication complexes (pre-RCs at replication origins. The pre-RC assembly reaction involves the loading of a presumptive replicative helicase, the MCM2-7 complexes, onto chromatin by the origin recognition complex (ORC and two essential factors, CDC6 and Cdt1. The eukaryotic cell cycle is driven by the periodic activation and inactivation of cyclin-dependent kinases (Cdks and assembly of pre-RCs can only occur during the low Cdk activity period from late mitosis through G1 phase, with inappropriate re-assembly suppressed during S, G2, and M phases. It was originally suggested that inhibition of Cdt1 function after S phase in vertebrate cells is due to geminin binding and that Cdt1 hyperfunction resulting from Cdt1-geminin imbalance induces re-replication. However, recent progress has revealed that Cdt1 activity is more strictly regulated by two other mechanisms in addition to geminin: (1 functional and SCFSkp2-mediated proteolytic regulation through phosphorylation by Cdks; and (2 replication-coupled proteolysis mediated by the Cullin4-DDB1Cdt2 ubiquitin ligase and PCNA, an eukaryotic sliding clamp stimulating replicative DNA polymerases. The tight regulation implies that Cdt1 control is especially critical for the regulation of DNA replication in mammalian cells. Indeed, Cdt1 overexpression evokes chromosomal damage even without re-replication. Furthermore, deregulated Cdt1 induces chromosomal instability in normal human cells. Since Cdt1 is overexpressed in cancer cells, this could be a new molecular mechanism leading to carcinogenesis. In this review, recent insights into Cdt1 function and regulation in mammalian cells are discussed.

  19. Effects of activated fibroblasts on phenotype modulation, EGFR signalling and cell cycle regulation in OSCC cells

    Energy Technology Data Exchange (ETDEWEB)

    Berndt, Alexander, E-mail: alexander.berndt@med.uni-jena.de [Center for Molecular Biomedicine, Institute of Pathology, Jena University Hospital, 07740 Jena (Germany); Büttner, Robert, E-mail: Robert-Buettner@gmx.net [Institute of Biochemistry and Biophysics, Friedrich Schiller University Jena, 07740 Jena (Germany); Gühne, Stefanie, E-mail: stefanie_guehne@gmx.net [Center for Molecular Biomedicine, Institute of Pathology, Jena University Hospital, 07740 Jena (Germany); Gleinig, Anna, E-mail: annagleinig@yahoo.com [Center for Molecular Biomedicine, Institute of Pathology, Jena University Hospital, 07740 Jena (Germany); Richter, Petra, E-mail: P.Richter@med.uni-jena.de [Center for Molecular Biomedicine, Institute of Pathology, Jena University Hospital, 07740 Jena (Germany); Chen, Yuan, E-mail: Yuan.Chen@med.uni-jena.de [Center for Molecular Biomedicine, Institute of Pathology, Jena University Hospital, 07740 Jena (Germany); Franz, Marcus, E-mail: Marcus.Franz@med.uni-jena.de [Clinic of Internal Medicine I, Jena University Hospital, 07740 Jena (Germany); Liebmann, Claus, E-mail: Claus.Liebmann@uni-jena.de [Institute of Biochemistry and Biophysics, Friedrich Schiller University Jena, 07740 Jena (Germany)

    2014-04-01

    Crosstalk between carcinoma associated fibroblasts (CAFs) and oral squamous cell carcinoma (OSCC) cells is suggested to mediate phenotype transition of cancer cells as a prerequisite for tumour progression, to predict patients’ outcome, and to influence the efficacy of EGFR inhibitor therapies. Here we investigate the influence of activated fibroblasts as a model for CAFs on phenotype and EGFR signalling in OSCC cells in vitro. For this, immortalised hTERT-BJ1 fibroblasts were activated with TGFβ1 and PDGFAB to generate a myofibroblast or proliferative phenotype, respectively. Conditioned media (FCM{sub TGF}, FCM{sub PDGF}) were used to stimulate PE/CA-PJ15 OSCC cells. Results were compared to the effect of conditioned media of non-stimulated fibroblasts (FCM{sub B}). FCM{sub TGF} stimulation leads to an up-regulation of vimentin in the OSCC cells and an enhancement of invasive behaviour, indicating EMT-like effects. Similarly, FCM{sub TGF}≫FCM{sub PDGF} induced up-regulation of EGFR, but not of ErbB2/ErbB3. In addition, we detected an increase in basal activities of ERK, PI3K/Akt and Stat3 (FCM{sub TGF}>FCM{sub PDGF}) accompanied by protein interaction of vimentin with pERK. These effects are correlated with an increased proliferation. In summary, our results suggest that the activated myofibroblast phenotype provides soluble factors which are able to induce EMT-like phenomena and to increase EGFR signalling as well as cell proliferation in OSCC cells. Our results indicate a possible influence of activated myofibroblasts on EGFR-inhibitor therapy. Therefore, CAFs may serve as promising novel targets for combined therapy strategies. - Highlights: • A cell culture model for cancer associated fibroblasts is described. • The mutual interaction with OSCC cells leads to up-regulation of EGFR in tumour cells. • mCAF induces EGFR downstream signalling with increased proliferation in OSCC. • Erk activation is associated with protein interaction with vimentin

  20. Effects of activated fibroblasts on phenotype modulation, EGFR signalling and cell cycle regulation in OSCC cells

    International Nuclear Information System (INIS)

    Berndt, Alexander; Büttner, Robert; Gühne, Stefanie; Gleinig, Anna; Richter, Petra; Chen, Yuan; Franz, Marcus; Liebmann, Claus

    2014-01-01

    Crosstalk between carcinoma associated fibroblasts (CAFs) and oral squamous cell carcinoma (OSCC) cells is suggested to mediate phenotype transition of cancer cells as a prerequisite for tumour progression, to predict patients’ outcome, and to influence the efficacy of EGFR inhibitor therapies. Here we investigate the influence of activated fibroblasts as a model for CAFs on phenotype and EGFR signalling in OSCC cells in vitro. For this, immortalised hTERT-BJ1 fibroblasts were activated with TGFβ1 and PDGFAB to generate a myofibroblast or proliferative phenotype, respectively. Conditioned media (FCM TGF , FCM PDGF ) were used to stimulate PE/CA-PJ15 OSCC cells. Results were compared to the effect of conditioned media of non-stimulated fibroblasts (FCM B ). FCM TGF stimulation leads to an up-regulation of vimentin in the OSCC cells and an enhancement of invasive behaviour, indicating EMT-like effects. Similarly, FCM TGF ≫FCM PDGF induced up-regulation of EGFR, but not of ErbB2/ErbB3. In addition, we detected an increase in basal activities of ERK, PI3K/Akt and Stat3 (FCM TGF >FCM PDGF ) accompanied by protein interaction of vimentin with pERK. These effects are correlated with an increased proliferation. In summary, our results suggest that the activated myofibroblast phenotype provides soluble factors which are able to induce EMT-like phenomena and to increase EGFR signalling as well as cell proliferation in OSCC cells. Our results indicate a possible influence of activated myofibroblasts on EGFR-inhibitor therapy. Therefore, CAFs may serve as promising novel targets for combined therapy strategies. - Highlights: • A cell culture model for cancer associated fibroblasts is described. • The mutual interaction with OSCC cells leads to up-regulation of EGFR in tumour cells. • mCAF induces EGFR downstream signalling with increased proliferation in OSCC. • Erk activation is associated with protein interaction with vimentin as sign of EMT. • Results qualify

  1. Phytophthora capsici homologue of the cell cycle regulator SDA1 is required for sporangial morphology, mycelial growth and plant infection.

    Science.gov (United States)

    Zhu, Chunyuan; Yang, Xiaoyan; Lv, Rongfei; Li, Zhuang; Ding, Xiaomeng; Tyler, Brett M; Zhang, Xiuguo

    2016-04-01

    SDA1 encodes a highly conserved protein that is widely distributed in eukaryotic organisms. SDA1 is essential for cell cycle progression and organization of the actin cytoskeleton in yeasts and humans. In this study, we identified a Phytophthora capsici orthologue of yeast SDA1, named PcSDA1. In P. capsici, PcSDA1 is strongly expressed in three asexual developmental states (mycelium, sporangia and germinating cysts), as well as late in infection. Silencing or overexpression of PcSDA1 in P. capsici transformants affected the growth of hyphae and sporangiophores, sporangial development, cyst germination and zoospore release. Phalloidin staining confirmed that PcSDA1 is required for organization of the actin cytoskeleton. Moreover, 4',6-diamidino-2-phenylindole (DAPI) staining and PcSDA1-green fluorescent protein (GFP) fusions revealed that PcSDA1 is involved in the regulation of nuclear distribution in hyphae and sporangia. Both silenced and overexpression transformants showed severely diminished virulence. Thus, our results suggest that PcSDA1 plays a similar role in the regulation of the actin cytoskeleton and nuclear division in this filamentous organism as in non-filamentous yeasts and human cells. © 2015 BSPP and John Wiley & Sons Ltd.

  2. Lamprey Prohibitin2 Arrest G2/M Phase Transition of HeLa Cells through Down-regulating Expression and Phosphorylation Level of Cell Cycle Proteins.

    Science.gov (United States)

    Shi, Ying; Guo, Sicheng; Wang, Ying; Liu, Xin; Li, Qingwei; Li, Tiesong

    2018-03-02

    Prohibitin 2(PHB2) is a member of the SFPH trans-membrane family proteins. It is a highly conserved and functionally diverse protein that plays an important role in preserving the structure and function of the mitochondria. In this study, the lamprey PHB2 gene was expressed in HeLa cells to investigate its effect on cell proliferation. The effect of Lm-PHB2 on the proliferation of HeLa cells was determined by treating the cells with pure Lm-PHB2 protein followed by MTT assay. Using the synchronization method with APC-BrdU and PI double staining revealed rLm-PHB2 treatment induced the decrease of both S phase and G0/G1 phase and then increase of G2/M phase. Similarly, cells transfected with pEGFP-N1-Lm-PHB2 also exhibited remarkable reduction in proliferation. Western blot and quantitative real-time PCR(qRT-PCR) assays suggested that Lm-PHB2 caused cell cycle arrest in HeLa cells through inhibition of CDC25C and CCNB1 expression. According to our western blot analysis, Lm-PHB2 was also found to reduce the expression level of Wee1 and PLK1 and the phosphorylation level of CCNB1, CDC25C and CDK1 in HeLa cells. Lamprey prohibitin 2 could arrest G2/M phase transition of HeLa cells through down-regulating expression and phosphorylation level of cell cycle proteins.

  3. Dynamics of the cell-cycle network under genome-rewiring perturbations

    International Nuclear Information System (INIS)

    Katzir, Yair; Elhanati, Yuval; Braun, Erez; Averbukh, Inna

    2013-01-01

    The cell-cycle progression is regulated by a specific network enabling its ordered dynamics. Recent experiments supported by computational models have shown that a core of genes ensures this robust cycle dynamics. However, much less is known about the direct interaction of the cell-cycle regulators with genes outside of the cell-cycle network, in particular those of the metabolic system. Following our recent experimental work, we present here a model focusing on the dynamics of the cell-cycle core network under rewiring perturbations. Rewiring is achieved by placing an essential metabolic gene exclusively under the regulation of a cell-cycle's promoter, forcing the cell-cycle network to function under a multitasking challenging condition; operating in parallel the cell-cycle progression and a metabolic essential gene. Our model relies on simple rate equations that capture the dynamics of the relevant protein–DNA and protein–protein interactions, while making a clear distinction between these two different types of processes. In particular, we treat the cell-cycle transcription factors as limited ‘resources’ and focus on the redistribution of resources in the network during its dynamics. This elucidates the sensitivity of its various nodes to rewiring interactions. The basic model produces the correct cycle dynamics for a wide range of parameters. The simplicity of the model enables us to study the interface between the cell-cycle regulation and other cellular processes. Rewiring a promoter of the network to regulate a foreign gene, forces a multitasking regulatory load. The higher the load on the promoter, the longer is the cell-cycle period. Moreover, in agreement with our experimental results, the model shows that different nodes of the network exhibit variable susceptibilities to the rewiring perturbations. Our model suggests that the topology of the cell-cycle core network ensures its plasticity and flexible interface with other cellular processes

  4. The Cell Cycle–Regulated Genes of Schizosaccharomyces pombe

    Science.gov (United States)

    Oliva, Anna; Rosebrock, Adam; Ferrezuelo, Francisco; Pyne, Saumyadipta; Chen, Haiying; Skiena, Steve

    2005-01-01

    Many genes are regulated as an innate part of the eukaryotic cell cycle, and a complex transcriptional network helps enable the cyclic behavior of dividing cells. This transcriptional network has been studied in Saccharomyces cerevisiae (budding yeast) and elsewhere. To provide more perspective on these regulatory mechanisms, we have used microarrays to measure gene expression through the cell cycle of Schizosaccharomyces pombe (fission yeast). The 750 genes with the most significant oscillations were identified and analyzed. There were two broad waves of cell cycle transcription, one in early/mid G2 phase, and the other near the G2/M transition. The early/mid G2 wave included many genes involved in ribosome biogenesis, possibly explaining the cell cycle oscillation in protein synthesis in S. pombe. The G2/M wave included at least three distinctly regulated clusters of genes: one large cluster including mitosis, mitotic exit, and cell separation functions, one small cluster dedicated to DNA replication, and another small cluster dedicated to cytokinesis and division. S. pombe cell cycle genes have relatively long, complex promoters containing groups of multiple DNA sequence motifs, often of two, three, or more different kinds. Many of the genes, transcription factors, and regulatory mechanisms are conserved between S. pombe and S. cerevisiae. Finally, we found preliminary evidence for a nearly genome-wide oscillation in gene expression: 2,000 or more genes undergo slight oscillations in expression as a function of the cell cycle, although whether this is adaptive, or incidental to other events in the cell, such as chromatin condensation, we do not know. PMID:15966770

  5. Assessment of single nucleotide polymorphisms in screening 52 DNA repair and cell cycle control genes in Fanconi anemia patients

    Directory of Open Access Journals (Sweden)

    Petrović Sandra

    2015-01-01

    Full Text Available Fanconi anemia (FA is a rare genetically heterogeneous disorder associated with bone marrow failure, birth defects and cancer susceptibility. Apart from the disease- causing mutations in FANC genes, the identification of specific DNA variations, such as single nucleotide polymorphisms (SNPs, in other candidate genes may lead to a better clinical description of this condition enabling individualized treatment with improvement of the prognosis. In this study, we have assessed 95 SNPs located in 52 key genes involved in base excision repair (BER, nucleotide excision repair (NER, mismatch repair (MMR, double strand break (DSB repair and cell cycle control using a DNA repair chip (Asper Biotech, Estonia which includes most of the common variants for the candidate genes. The SNP genotyping was performed in five FA-D2 patients and in one FA-A patient. The polymorphisms studied were synonymous (n=10, nonsynonymous (missense (n=52 and in non-coding regions of the genome (introns and 5 ‘and 3’ untranslated regions (UTR (n=33. Polymorphisms found at the homozygous state are selected for further analysis. Our results have shown a significant inter-individual variability among patients in the type and the frequency of SNPs and also elucidate the need for further studies of polymorphisms located in ATM, APEX APE 1, XRCC1, ERCC2, MSH3, PARP4, NBS1, BARD1, CDKN1B, TP53 and TP53BP1 which may be of great importance for better clinical description of FA. In addition, the present report recommends the use of SNPs as predictive and prognostic genetic markers to individualize therapy of FA patients. [Projekat Ministarstva nauke Republike Srbije, br. 173046

  6. The homeoprotein DLX3 and tumor suppressor p53 co-regulate cell cycle progression and squamous tumor growth.

    Science.gov (United States)

    Palazzo, E; Kellett, M; Cataisson, C; Gormley, A; Bible, P W; Pietroni, V; Radoja, N; Hwang, J; Blumenberg, M; Yuspa, S H; Morasso, M I

    2016-06-16

    Epidermal homeostasis depends on the coordinated control of keratinocyte cell cycle. Differentiation and the alteration of this balance can result in neoplastic development. Here we report on a novel DLX3-dependent network that constrains epidermal hyperplasia and squamous tumorigenesis. By integrating genetic and transcriptomic approaches, we demonstrate that DLX3 operates through a p53-regulated network. DLX3 and p53 physically interact on the p21 promoter to enhance p21 expression. Elevating DLX3 in keratinocytes produces a G1-S blockade associated with p53 signature transcriptional profiles. In contrast, DLX3 loss promotes a mitogenic phenotype associated with constitutive activation of ERK. DLX3 expression is lost in human skin cancers and is extinguished during progression of experimentally induced mouse squamous cell carcinoma (SCC). Reinstatement of DLX3 function is sufficient to attenuate the migration of SCC cells, leading to decreased wound closure. Our data establish the DLX3-p53 interplay as a major regulatory axis in epidermal differentiation and suggest that DLX3 is a modulator of skin carcinogenesis.

  7. Fanconi anemia proteins localize to chromatin and the nuclear matrix in a DNA damage- and cell cycle-regulated manner.

    Science.gov (United States)

    Qiao, F; Moss, A; Kupfer, G M

    2001-06-29

    Fanconi anemia (FA) is a genetic disease characterized by congenital defects, bone marrow failure, and cancer susceptibility. Cells from patients with FA exhibit genomic instability and hypersensitivity to DNA cross linking agents such as mitomycin C. Despite the identification of seven complementation groups and the cloning of six genes, the function of the encoded gene products remains elusive. The FancA (Fanconi anemia complementation group A), FancC, and FancG proteins have been detected within a nuclear complex, but no change in level, binding, or localization has been reported as a result of drug treatment or cell cycle. We show that in immunofluorescence studies, FancA appears as a non-nucleolar nuclear protein that is excluded from condensed, mitotic chromosomes. Biochemical fractionation reveals that the FA proteins are found in nuclear matrix and chromatin and that treatment with mitomycin C results in increase of the FA proteins in nuclear matrix and chromatin fractions. This induction occurs in wild-type cells and mutant FA-D (Fanconi complementation group D) cells but not in mutant FA-A cells. Immunoprecipitation of FancA protein in chromatin demonstrates the coprecipitation of FancA, FancC, and FancG, showing that the FA proteins move together as a complex. Also, fractionation of mitotic cells confirms the lack of FA proteins in chromatin or the nuclear matrix. Furthermore, phosphorylation of FancG was found to be temporally correlated with exit of the FA complex from chromosomes at mitosis. Taken together, these findings suggest a role for FA proteins in chromatin and nuclear matrix.

  8. Genome Wide Expression Profiling of Cancer Cell Lines Cultured in Microgravity Reveals Significant Dysregulation of Cell Cycle and MicroRNA Gene Networks.

    Directory of Open Access Journals (Sweden)

    Prasanna Vidyasekar

    Full Text Available Zero gravity causes several changes in metabolic and functional aspects of the human body and experiments in space flight have demonstrated alterations in cancer growth and progression. This study reports the genome wide expression profiling of a colorectal cancer cell line-DLD-1, and a lymphoblast leukemic cell line-MOLT-4, under simulated microgravity in an effort to understand central processes and cellular functions that are dysregulated among both cell lines. Altered cell morphology, reduced cell viability and an aberrant cell cycle profile in comparison to their static controls were observed in both cell lines under microgravity. The process of cell cycle in DLD-1 cells was markedly affected with reduced viability, reduced colony forming ability, an apoptotic population and dysregulation of cell cycle genes, oncogenes, and cancer progression and prognostic markers. DNA microarray analysis revealed 1801 (upregulated and 2542 (downregulated genes (>2 fold in DLD-1 cultures under microgravity while MOLT-4 cultures differentially expressed 349 (upregulated and 444 (downregulated genes (>2 fold under microgravity. The loss in cell proliferative capacity was corroborated with the downregulation of the cell cycle process as demonstrated by functional clustering of DNA microarray data using gene ontology terms. The genome wide expression profile also showed significant dysregulation of post transcriptional gene silencing machinery and multiple microRNA host genes that are potential tumor suppressors and proto-oncogenes including MIR22HG, MIR17HG and MIR21HG. The MIR22HG, a tumor-suppressor gene was one of the highest upregulated genes in the microarray data showing a 4.4 log fold upregulation under microgravity. Real time PCR validated the dysregulation in the host gene by demonstrating a 4.18 log fold upregulation of the miR-22 microRNA. Microarray data also showed dysregulation of direct targets of miR-22, SP1, CDK6 and CCNA2.

  9. Rare sugar D-allose induces specific up-regulation of TXNIP and subsequent G1 cell cycle arrest in hepatocellular carcinoma cells by stabilization of p27kip1.

    Science.gov (United States)

    Yamaguchi, Fuminori; Takata, Maki; Kamitori, Kazuyo; Nonaka, Machiko; Dong, Youyi; Sui, Li; Tokuda, Masaaki

    2008-02-01

    'Rare sugars' are defined as monosaccharides that exist in nature but are only present in limited quantities. The development of mass production method of rare sugars revealed some interesting physiological effects of these on animal cells, but the mechanisms have not been well studied. We examined the effect of D-allose on the proliferation of cancer cells and the underlying molecular mechanism of the action. The HuH-7 hepatocellular carcinoma cells were treated with various monosaccharides for 48 h and D-allose was shown to inhibit cell growth by 40% in a dose-dependent manner. D-allose induced G1 cell cycle arrest but not apoptosis. The microarray analysis revealed that D-allose significantly up-regulated thioredoxin interacting protein (TXNIP) gene expression, which is often suppressed in tumor cells and western blot analysis confirmed its increase at protein level. The overexpression of TXNIP also induced G1 cell cycle arrest. Analysis of cell cycle regulatory genes showed p27kip1, a key regulator of G1/S cell cycle transition, to be increased at the protein but not the transcriptional level. Protein interaction between TXNIP and jab1, and p27kip1 and jab1, was observed, suggesting stabilization of p27kip1 protein by the competitive inhibition of jab1-mediated nuclear export of p27kip1 by TXNIP. In addition, increased interaction and nuclear localization of TXNIP and p27kip1 were apparent after D-allose treatment. Our findings surprisingly suggest that D-allose, a simple monosaccharide, may act as a novel anticancer agent via unique TXNIP induction and p27kip1 protein stabilization.

  10. Gene activation by UV light, fungal elicitor or fungal infection in Petroselinum crispum is correlated with repression of cell cycle-related genes

    International Nuclear Information System (INIS)

    Logemann, E.; Wu ShengCheng; Schröder, J.; Schmelzer, E.; Somssich, I.E.; Hahlbrock, K.

    1995-01-01

    The effects of UV light or fungal elicitors on plant cells have so far been studied mostly with respect to defense-related gene activation. Here, an inverse correlation of these stimulatory effects with the activities of several cell cycle-related genes is demonstrated. Concomitant with the induction of flavonoid biosynthetic enzymes in UV-irradiated cell suspension cultures of parsley (Petroselinum crispum), total histone synthesis declined to about half the initial rate. A subclass of the histone H3 gene family was selected to demonstrate the close correlation of its expression with cell division, both in intact plants and cultured cells. Using RNA-blot and run-on transcription assays, it was shown that one arbitrarily selected subclass of each of the histone H2A, H2B, H3 and H4 gene families and of the genes encoding a p34cdc2 protein kinase and a mitotic cyclin were transcriptionally repressed in UV-irradiated as well as fungal elicitor-treated parsley cells. The timing and extent of repression differed between the two stimuli; the response to light was more transient and smaller in magnitude. These differential responses to light and elicitor were inversely correlated with the induction of phenylalanine ammonia-lyase, a key enzyme of phenylpropanoid metabolism. Essentially the same result was obtained with a defined oligopeptide elicitor, indicating that the same signaling pathway is responsible for defense-related gene activation and cell cycle-related gene repression. A temporary (UV light) or long-lasting (fungal elicitor) cessation of cell culture growth is most likely due to an arrest of cell division which may be a prerequisite for full commitment of the cells to transcriptional activation of full commitment of the cells to transcriptional activation of pathways involved in UV protection or pathogen defense. This conclusion is corroborated by the observation that the histone H3 mRNA level greatly declined around fungal infection sites in young parsley

  11. Mutations in new cell cycle genes that fail to complement a multiply mutant third chromosome of Drosophila.

    Science.gov (United States)

    White-Cooper, H; Carmena, M; Gonzalez, C; Glover, D M

    1996-11-01

    We have simultaneously screened for new alleles and second site mutations that fail to complement five cell cycle mutations of Drosphila carried on a single third chromosome (gnu, polo, mgr, asp, stg). Females that are either transheterozygous for scott of the antartic (scant) and polo, or homozygous for scant produce embryos that show mitotic defects. A maternal effect upon embryonic mitoses is also seen in embryos derived from females transheterozygous with helter skelter (hsk) and either mgr or asp. cleopatra (cleo), fails to complement asp but is not uncovered by a deficiency for asp. The mitotic phenotype of larvae heterozygous for cleo and the multiple mutant chromosome is similar to weak alleles of asp, but there are no defects in male meiosis. Mutations that failed to complement stg fell into two complementation groups corresponding to stg and a new gene noose. Three of the new stg alleles are early zygotic lethals, whereas the fourth is a pharate adult lethal allele that affects both mitosis and meiosis. Mutations in noose fully complement a small deficiency that removes stg, but when placed in trans to certain stg alleles, result in late lethality and mitotic abnormalities in larval brains.

  12. E2F1-Mediated Upregulation of p19INK4d Determines Its Periodic Expression during Cell Cycle and Regulates Cellular Proliferation

    OpenAIRE

    Carcagno, Abel L.; Marazita, Mariela C.; Ogara, María F.; Ceruti, Julieta M.; Sonzogni, Silvina V.; Scassa, María E.; Giono, Luciana E.; Cánepa, Eduardo T.

    2011-01-01

    Background: A central aspect of development and disease is the control of cell proliferation through regulation of the mitotic cycle. Cell cycle progression and directionality requires an appropriate balance of positive and negative regulators whose expression must fluctuate in a coordinated manner. p19INK4d, a member of the INK4 family of CDK inhibitors, has a unique feature that distinguishes it from the remaining INK4 and makes it a likely candidate for contributing to the directionality o...

  13. The circadian molecular clock regulates adult hippocampal neurogenesis by controlling the timing of cell-cycle entry and exit.

    Science.gov (United States)

    Bouchard-Cannon, Pascale; Mendoza-Viveros, Lucia; Yuen, Andrew; Kærn, Mads; Cheng, Hai-Ying M

    2013-11-27

    The subgranular zone (SGZ) of the adult hippocampus contains a pool of quiescent neural progenitor cells (QNPs) that are capable of entering the cell cycle and producing newborn neurons. The mechanisms that control the timing and extent of adult neurogenesis are not well understood. Here, we show that QNPs of the adult SGZ express molecular-clock components and proliferate in a rhythmic fashion. The clock proteins PERIOD2 and BMAL1 are critical for proper control of neurogenesis. The absence of PERIOD2 abolishes the gating of cell-cycle entrance of QNPs, whereas genetic ablation of bmal1 results in constitutively high levels of proliferation and delayed cell-cycle exit. We use mathematical model simulations to show that these observations may arise from clock-driven expression of a cell-cycle inhibitor that targets the cyclin D/Cdk4-6 complex. Our findings may have broad implications for the circadian clock in timing cell-cycle events of other stem cell populations throughout the body. Copyright © 2013 The Authors. Published by Elsevier Inc. All rights reserved.

  14. The Circadian Molecular Clock Regulates Adult Hippocampal Neurogenesis by Controlling the Timing of Cell-Cycle Entry and Exit

    Directory of Open Access Journals (Sweden)

    Pascale Bouchard-Cannon

    2013-11-01

    Full Text Available The subgranular zone (SGZ of the adult hippocampus contains a pool of quiescent neural progenitor cells (QNPs that are capable of entering the cell cycle and producing newborn neurons. The mechanisms that control the timing and extent of adult neurogenesis are not well understood. Here, we show that QNPs of the adult SGZ express molecular-clock components and proliferate in a rhythmic fashion. The clock proteins PERIOD2 and BMAL1 are critical for proper control of neurogenesis. The absence of PERIOD2 abolishes the gating of cell-cycle entrance of QNPs, whereas genetic ablation of bmal1 results in constitutively high levels of proliferation and delayed cell-cycle exit. We use mathematical model simulations to show that these observations may arise from clock-driven expression of a cell-cycle inhibitor that targets the cyclin D/Cdk4-6 complex. Our findings may have broad implications for the circadian clock in timing cell-cycle events of other stem cell populations throughout the body.

  15. Immunohistochemical investigation of cell cycle and apoptosis regulators (Survivin, β-Catenin, P53, Caspase 3 in canine appendicular osteosarcoma

    Directory of Open Access Journals (Sweden)

    Bongiovanni Laura

    2012-06-01

    Full Text Available Abstract Background Osteosarcoma (OSA represents the most common canine primary bone tumour. Despite several pathways have been investigated so far, few molecules have been identified as prognostic tools or potential therapeutic targets, and there is still the need to find out molecular pathways with specific influence over OSA progression to facilitate earlier prognosis and treatment. Aims of the present study were to evaluate the immunohistochemical pattern and levels of expression of a panel of molecules (survivin, β-catenin, caspase 3 -inactive and active forms- and p53 involved in cell cycle and apoptosis regulation in canine OSA samples, known to be of interest in the study also of human OSA, and to detect specific relations among them and with histological tumour grade, disease free interval (DFI and overall survival (OS. Results Nuclear β-catenin immunostaining was detected in normal osteoblasts adjacent to the tumour, and in 47% of the cases. Cytoplasmic and/or membranous immunostaining were also observed. Nuclear survivin and p53 positive cells were found in all cases. Moderate/high cytoplasmic β-catenin expression (≥10% positive cells was significantly associated with the development of metastasis (P = 0.014; moderate/high nuclear p53 expression (≥10% positive cells was significantly associated with moderate/high histological grade (P = 0.017 and shorter OS (P = 0.049. Moderate/high nuclear survivin expression (≥15% positive cells showed a tendency toward a longer OS (P = 0,088. Conclusions The present results confirmed p53 as negative prognostic marker, while suggested survivin as a potential positive prognostic indicator, rather than indicative of a poor prognosis. The detection of nuclear β-catenin immunostaining in normal osteoblasts and the absent/low expression in most of the OSAs, suggested that this pathway could not play a major role in oncogenic transformation of canine osteoblasts. Further studies

  16. [Circadian rhythm variation of the clock genes Per1 and cell cycle related genes in different stages of carcinogenesis of buccal mucosa in animal model].

    Science.gov (United States)

    Tan, Xuemei; Ye, Hua; Yang, Kai; Chen, Dan; Tang, Hong

    2015-07-01

    To investigate the expression and circadian rhythm variation of biological clock gene Per1 and cell cycle genes p53, CyclinD1, cyclin-dependent kinases (CDK1), CyclinB1 in different stages of carcinogenesis in buccal mucosa and its relationship with the development of buccal mucosa carcinoma. Ninety golden hamsters were housed under 12 hours light-12 hours dark cycles, and the model of buccal squamous cell carcinoma was established by using the dimethylbenzanthracene (DMBA) to smear the golden hamster buccal mucosa. Before the DMBA was used and after DMBA was used 6 weeks and 14 weeks respectively, the golden hamsters were sacrificed at 6 different time points (5 rats per time point) within 24 hour, including 4, 8, 12, 16, 20 and 24 hour after lights onset (HALO), and the normal buccal mucosa, precancerous lesions and cancer tissue were obtained, respectively. HE stained sections were prepared to observe the canceration of each tissue. Real time RT-PCR was used to detect the mRNA expression of Per1, p53, CyclinD1, CDK1 and CyclinB1, and a cosine analysis method was applied to determine the circadian rhythm variation of Per1, p53, CyclinD1, CDK1 and CyclinB1 mRNA expression, which were characterized by median, amplitude and acrophase. The expression of Per1, p53, CDK1 and CyclinD1 mRNA in 6 different time points within 24 hours in the tissues of three different stages of carcinogenesis had circadian rhythm, respectively. However, the CyclinB1 mRNA was expressed with circadian rhythm just in normal and cancer tissue (P circadian rhythm was in disorder (P > 0.05). As the development of carcinoma, the median of Per1 and p53 mRNA expression were significantly decreased (P circadian rhythm of clock gene Per1 and cell cycle genes p53, CyclinD1, CDK1, CyclinB1 expression remarkably varied with the occurrence and development of carcinoma. Further research into the interaction between circadian and cell cycle of two cycle activity and relationship with the carcinogenesis may

  17. A low protein diet during pregnancy provokes a lasting shift of hepatic expression of genes related to cell cycle throughout ontogenesis in a porcine model

    Directory of Open Access Journals (Sweden)

    Oster Michael

    2012-03-01

    Full Text Available Abstract Background In rodent models and in humans the impact of gestational diets on the offspring's phenotype was shown experimentally and epidemiologically. Adverse environmental conditions during fetal development provoke an intrauterine adaptive response termed 'fetal programming', which may lead to both persistently biased responsiveness to extrinsic factors and permanent consequences for the organismal phenotype. This leads to the hypothesis that the offspring's transcriptome exhibits short-term and long-term changes, depending on the maternal diet. In order to contribute to a comprehensive inventory of genes and functional networks that are targets of nutritional programming initiated during fetal life, we applied whole-genome microarrays for expression profiling in a longitudinal experimental design covering prenatal, perinatal, juvenile, and adult ontogenetic stages in a porcine model. Pregnant sows were fed either a gestational low protein diet (LP, 6% CP or an adequate protein diet (AP, 12% CP. All offspring was nursed by foster sows receiving standard diets. After weaning, all offspring was fed standard diets ad libitum. Results Analyses of the hepatic gene expression of the offspring at prenatal (94 dies post conceptionem, dpc and postnatal stages (1, 28, 188 dies post natum, dpn included comparisons between dietary groups within stages as well as comparisons between ontogenetic stages within diets to separate diet-specific transcriptional changes and maturation processes. We observed differential expression of genes related to lipid metabolism (e.g. Fatty acid metabolism, Biosynthesis of steroids, Synthesis and degradation of ketone bodies, FA elongation in mitochondria, Bile acid synthesis and cell cycle regulation (e.g. Mitotic roles of PLK, G1/S checkpoint regulation, G2/M DNA damage checkpoint regulation. Notably, at stage 1 dpn no regulation of a distinct pathway was found in LP offspring. Conclusions The transcriptomic

  18. Site-Specific Phosphorylation of Ikaros Induced by Low-Dose Ionizing Radiation Regulates Cell Cycle Progression of B Lymphoblast Through CK2 and AKT Activation.

    Science.gov (United States)

    Cho, Seong-Jun; Kang, Hana; Kim, Min Young; Lee, Jung Eun; Kim, Sung Jin; Nam, Seon Young; Kim, Ji Young; Kim, Hee Sun; Pyo, Suhkneung; Yang, Kwang Hee

    2016-04-01

    To determine how low-dose ionizing radiation (LDIR) regulates B lympho-proliferation and its molecular mechanism related with Ikaros, transcription factor. Splenocytes and IM-9 cells were uniformly irradiated with various doses of a (137)Cs γ-source, and cell proliferation was analyzed. To determine the LDIR-specific phosphorylation of Ikaros, immunoprecipitation and Western blot analysis were performed. To investigate the physiologic function of LDIR-mediatied Ikaros phosphorylation, Ikaros mutants at phosphorylation sites were generated, and cell cycle analysis was performed. First, we found that LDIR enhances B lymphoblast proliferation in an Ikaros-dependent manner. Moreover, we found that LDIR elevates the phosphorylation level of Ikaros protein. Interestingly, we showed that CK2 and AKT are involved in LDIR-induced Ikaros phosphorylation and capable of regulating DNA binding activity of Ikaros via specific phosphorylation. Finally, we identified LDIR-specific Ikaros phosphorylation sites at S391/S393 and showed that the Ikaros phosphorylations at these sites control Ikaros's ability to regulate G1/S cell cycle progression. Low-dose ionizing radiation specifically phosphorylates Ikaros protein at Ser 391/393 residues to regulate cell cycle progression in B lymphoblast. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Site-Specific Phosphorylation of Ikaros Induced by Low-Dose Ionizing Radiation Regulates Cell Cycle Progression of B Lymphoblast Through CK2 and AKT Activation

    International Nuclear Information System (INIS)

    Cho, Seong-Jun; Kang, Hana; Kim, Min Young; Lee, Jung Eun; Kim, Sung Jin; Nam, Seon Young; Kim, Ji Young; Kim, Hee Sun; Pyo, Suhkneung; Yang, Kwang Hee

    2016-01-01

    Purpose: To determine how low-dose ionizing radiation (LDIR) regulates B lympho-proliferation and its molecular mechanism related with Ikaros, transcription factor. Methods and Materials: Splenocytes and IM-9 cells were uniformly irradiated with various doses of a "1"3"7Cs γ-source, and cell proliferation was analyzed. To determine the LDIR-specific phosphorylation of Ikaros, immunoprecipitation and Western blot analysis were performed. To investigate the physiologic function of LDIR-mediatied Ikaros phosphorylation, Ikaros mutants at phosphorylation sites were generated, and cell cycle analysis was performed. Results: First, we found that LDIR enhances B lymphoblast proliferation in an Ikaros-dependent manner. Moreover, we found that LDIR elevates the phosphorylation level of Ikaros protein. Interestingly, we showed that CK2 and AKT are involved in LDIR-induced Ikaros phosphorylation and capable of regulating DNA binding activity of Ikaros via specific phosphorylation. Finally, we identified LDIR-specific Ikaros phosphorylation sites at S391/S393 and showed that the Ikaros phosphorylations at these sites control Ikaros's ability to regulate G1/S cell cycle progression. Conclusion: Low-dose ionizing radiation specifically phosphorylates Ikaros protein at Ser 391/393 residues to regulate cell cycle progression in B lymphoblast.

  20. Site-Specific Phosphorylation of Ikaros Induced by Low-Dose Ionizing Radiation Regulates Cell Cycle Progression of B Lymphoblast Through CK2 and AKT Activation

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Seong-Jun; Kang, Hana [KHNP Radiation Health Institute, Korea Hydro & Nuclear Power Co, Seoul (Korea, Republic of); Kim, Min Young [Department of Molecular Biology, College of Natural Sciences, Pusan National University, Busan (Korea, Republic of); Lee, Jung Eun; Kim, Sung Jin; Nam, Seon Young; Kim, Ji Young; Kim, Hee Sun [KHNP Radiation Health Institute, Korea Hydro & Nuclear Power Co, Seoul (Korea, Republic of); Pyo, Suhkneung [College of Pharmacy, Sungkyunkwan University, Suwon, Gyeonggi-do (Korea, Republic of); Yang, Kwang Hee, E-mail: kwangheey@khnp.co.kr [KHNP Radiation Health Institute, Korea Hydro & Nuclear Power Co, Seoul (Korea, Republic of)

    2016-04-01

    Purpose: To determine how low-dose ionizing radiation (LDIR) regulates B lympho-proliferation and its molecular mechanism related with Ikaros, transcription factor. Methods and Materials: Splenocytes and IM-9 cells were uniformly irradiated with various doses of a {sup 137}Cs γ-source, and cell proliferation was analyzed. To determine the LDIR-specific phosphorylation of Ikaros, immunoprecipitation and Western blot analysis were performed. To investigate the physiologic function of LDIR-mediatied Ikaros phosphorylation, Ikaros mutants at phosphorylation sites were generated, and cell cycle analysis was performed. Results: First, we found that LDIR enhances B lymphoblast proliferation in an Ikaros-dependent manner. Moreover, we found that LDIR elevates the phosphorylation level of Ikaros protein. Interestingly, we showed that CK2 and AKT are involved in LDIR-induced Ikaros phosphorylation and capable of regulating DNA binding activity of Ikaros via specific phosphorylation. Finally, we identified LDIR-specific Ikaros phosphorylation sites at S391/S393 and showed that the Ikaros phosphorylations at these sites control Ikaros's ability to regulate G1/S cell cycle progression. Conclusion: Low-dose ionizing radiation specifically phosphorylates Ikaros protein at Ser 391/393 residues to regulate cell cycle progression in B lymphoblast.

  1. MicroRNA-93 controls perfusion recovery after hindlimb ischemia by modulating expression of multiple genes in the cell cycle pathway.

    Science.gov (United States)

    Hazarika, Surovi; Farber, Charles R; Dokun, Ayotunde O; Pitsillides, Achillieas N; Wang, Tao; Lye, R John; Annex, Brian H

    2013-04-30

    MicroRNAs are key regulators of gene expression in response to injury, but there is limited knowledge of their role in ischemia-induced angiogenesis, such as in peripheral arterial disease. Here, we used an unbiased strategy and took advantage of different phenotypic outcomes that follow surgically induced hindlimb ischemia between inbred mouse strains to identify key microRNAs involved in perfusion recovery from hindlimb ischemia. From comparative microRNA profiling between inbred mouse strains that display profound differences in their extent of perfusion recovery after hindlimb ischemia, we found that the mouse strain with higher levels of microRNA-93 (miR-93) in hindlimb muscle before ischemia and the greater ability to upregulate miR-93 in response to ischemia had better perfusion recovery. In vitro, overexpression of miR-93 attenuated hypoxia-induced apoptosis in both endothelial and skeletal muscle cells and enhanced proliferation in both cell types. In addition, miR-93 overexpression enhanced endothelial cell tube formation. In vivo, miR-93 overexpression enhanced capillary density and perfusion recovery from hindlimb ischemia, and antagomirs to miR-93 attenuated perfusion recovery. Both in vitro and in vivo modulation of miR-93 resulted in alterations in the expression of >1 cell cycle pathway gene in 2 different cell types. Our data indicate that miR-93 enhances perfusion recovery from hindlimb ischemia by modulation of multiple genes that coordinate the functional pathways of cell proliferation and apoptosis. Thus, miR-93 is a strong potential target for pharmacological modulation to promote angiogenesis in ischemic tissue.

  2. Lineage-specific interface proteins match up the cell cycle and differentiation in embryo stem cells

    DEFF Research Database (Denmark)

    Re, Angela; Workman, Christopher; Waldron, Levi

    2014-01-01

    The shortage of molecular information on cell cycle changes along embryonic stem cell (ESC) differentiation prompts an in silico approach, which may provide a novel way to identify candidate genes or mechanisms acting in coordinating the two programs. We analyzed germ layer specific gene expression...... changes during the cell cycle and ESC differentiation by combining four human cell cycle transcriptome profiles with thirteen in vitro human ESC differentiation studies. To detect cross-talk mechanisms we then integrated the transcriptome data that displayed differential regulation with protein...... interaction data. A new class of non-transcriptionally regulated genes was identified, encoding proteins which interact systematically with proteins corresponding to genes regulated during the cell cycle or cell differentiation, and which therefore can be seen as interface proteins coordinating the two...

  3. Cdk1 activity acts as a quantitative platform for coordinating cell cycle progression with periodic transcription

    Science.gov (United States)

    Banyai, Gabor; Baïdi, Feriel; Coudreuse, Damien; Szilagyi, Zsolt

    2016-01-01

    Cell proliferation is regulated by cyclin-dependent kinases (Cdks) and requires the periodic expression of particular gene clusters in different cell cycle phases. However, the interplay between the networks that generate these transcriptional oscillations and the core cell cycle machinery remains largely unexplored. In this work, we use a synthetic regulable Cdk1 module to demonstrate that periodic expression is governed by quantitative changes in Cdk1 activity, with different clusters directly responding to specific activity levels. We further establish that cell cycle events neither participate in nor interfere with the Cdk1-driven transcriptional program, provided that cells are exposed to the appropriate Cdk1 activities. These findings contrast with current models that propose self-sustained and Cdk1-independent transcriptional oscillations. Our work therefore supports a model in which Cdk1 activity serves as a quantitative platform for coordinating cell cycle transitions with the expression of critical genes to bring about proper cell cycle progression. PMID:27045731

  4. Modifications in cell cycle kinetics and in expression of G1 phase-regulating proteins in human amniotic cells after exposure to electromagnetic fields and ionizing radiation.

    Science.gov (United States)

    Lange, S; Viergutz, T; Simkó, M

    2004-10-01

    Low-frequency electromagnetic fields are suspected of being involved in carcinogenesis, particularly in processes that could be related to cancer promotion. Because development of cancer is associated with deregulated cell growth and we previously observed a magnetic field-induced decrease in DNA synthesis [Lange et al. (2002) Alterations in the cell cycle and in the protein level of cyclin D1p, 21CIP1, and p16INK4a after exposure to 50 HZ. MF in human cells. Radiat. Environ. Biophys.41, 131], this study aims to document the influence of 50 Hz, 1 mT magnetic fields (MF), with or without initial gamma-ionizing radiation (IR), on the following cell proliferation-relevant parameters in human amniotic fluid cells (AFC): cell cycle distribution, expression of the G1 phase-regulating proteins Cdk4, cyclin D1, p21CIP1 and p16INK4a, and Cdk4 activity. While IR induced a G1 delay and a dose-dependent G2 arrest, no discernible changes in cell cycle kinetics were observed due to MF exposure. However, a significant decrease in the protein expression of cyclin D1 and an increase in p21CIP1- and p16INK4a-expression could be detected after exposure to MF alone. IR-exposure caused an augmentation of p21CIP1- and p16INK4a- levels as well, but did not alter cyclin D1 expression. A slight diminution of Cdk4 activity was noticed after MF exposure only, indicating that Cdk4 appears not to act as a mediator of MF- or IR-induced changes in the cell cycle of AFC cells. Co-exposure to MF/IR affected neither cell cycle distribution nor protein expression or kinase activity additionally or synergistically, and therefore MF seems not to modify the mutagenic potency of IR.

  5. The Gcn2 Regulator Yih1 Interacts with the Cyclin Dependent Kinase Cdc28 and Promotes Cell Cycle Progression through G2/M in Budding Yeast.

    Directory of Open Access Journals (Sweden)

    Richard C Silva

    Full Text Available The Saccharomyces cerevisiae protein Yih1, when overexpressed, inhibits the eIF2 alpha kinase Gcn2 by competing for Gcn1 binding. However, deletion of YIH1 has no detectable effect on Gcn2 activity, suggesting that Yih1 is not a general inhibitor of Gcn2, and has no phenotypic defect identified so far. Thus, its physiological role is largely unknown. Here, we show that Yih1 is involved in the cell cycle. Yeast lacking Yih1 displays morphological patterns and DNA content indicative of a delay in the G2/M phases of the cell cycle, and this phenotype is independent of Gcn1 and Gcn2. Accordingly, the levels of phosphorylated eIF2α, which show a cell cycle-dependent fluctuation, are not altered in cells devoid of Yih1. We present several lines of evidence indicating that Yih1 is in a complex with Cdc28. Yih1 pulls down endogenous Cdc28 in vivo and this interaction is enhanced when Cdc28 is active, suggesting that Yih1 modulates the function of Cdc28 in specific stages of the cell cycle. We also demonstrate, by Bimolecular Fluorescence Complementation, that endogenous Yih1 and Cdc28 interact with each other, confirming Yih1 as a bona fide Cdc28 binding partner. Amino acid substitutions within helix H2 of the RWD domain of Yih1 enhance Yih1-Cdc28 association. Overexpression of this mutant, but not of wild type Yih1, leads to a phenotype similar to that of YIH1 deletion, supporting the view that Yih1 is involved through Cdc28 in the regulation of the cell cycle. We further show that IMPACT, the mammalian homologue of Yih1, interacts with CDK1, the mammalian counterpart of Cdc28, indicating that the involvement with the cell cycle is conserved. Together, these data provide insights into the cellular function of Yih1/IMPACT, and provide the basis for future studies on the role of this protein in the cell cycle.

  6. Progesterone receptor blockade in human breast cancer cells decreases cell cycle progression through G2/M by repressing G2/M genes

    OpenAIRE

    Clare, Susan E.; Gupta, Akash; Choi, MiRan; Ranjan, Manish; Lee, Oukseub; Wang, Jun; Ivancic, David Z.; Kim, J. Julie; Khan, Seema A.

    2016-01-01

    Background The synthesis of specific, potent progesterone antagonists adds potential agents to the breast cancer prevention and treatment armamentarium. The identification of individuals who will benefit from these agents will be a critical factor for their clinical success. Methods We utilized telapristone acetate (TPA; CDB-4124) to understand the effects of progesterone receptor (PR) blockade on proliferation, apoptosis, promoter binding, cell cycle progression, and gene expression. We then...

  7. Analysis of a Novel 17q25 Cell Cycle Gene Homolog: Is it a Breast Tumor Suppressor Gene?

    National Research Council Canada - National Science Library

    Kalikin, Linda

    2000-01-01

    ... of these molecular reagents into successful tools for the medical management of breast cancer. We hypothesize that a 350 kb region on 17q25 detected by our allelic imbalance studies harbors a novel breast tumor suppressor gene...

  8. Cell Cycle Control by PTEN.

    Science.gov (United States)

    Brandmaier, Andrew; Hou, Sheng-Qi; Shen, Wen H

    2017-07-21

    Continuous and error-free chromosome inheritance through the cell cycle is essential for genomic stability and tumor suppression. However, accumulation of aberrant genetic materials often causes the cell cycle to go awry, leading to malignant transformation. In response to genotoxic stress, cells employ diverse adaptive mechanisms to halt or exit the cell cycle temporarily or permanently. The intrinsic machinery of cycling, resting, and exiting shapes the cellular response to extrinsic stimuli, whereas prevalent disruption of the cell cycle machinery in tumor cells often confers resistance to anticancer therapy. Phosphatase and tensin homolog (PTEN) is a tumor suppressor and a guardian of the genome that is frequently mutated or deleted in human cancer. Moreover, it is increasingly evident that PTEN deficiency disrupts the fundamental processes of genetic transmission. Cells lacking PTEN exhibit cell cycle deregulation and cell fate reprogramming. Here, we review the role of PTEN in regulating the key processes in and out of cell cycle to optimize genomic integrity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. MicroRNA-Related DNA Repair/Cell-Cycle Genes Independently Associated With Relapse After Radiation Therapy for Early Breast Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Gee, Harriet E., E-mail: harriet.gee@sydney.edu.au [The Kinghorn Cancer Centre & Cancer Research Division, Garvan Institute of Medical Research, Darlinghurst, NSW (Australia); The Chris O' Brien Lifehouse, Missenden Road, Camperdown, NSW (Australia); Central Clinical School, Sydney Medical School, University of Sydney, NSW (Australia); Buffa, Francesca M.; Harris, Adrian L. [Department of Medical Oncology, The University of Oxford, Oxford (United Kingdom); Toohey, Joanne M.; Carroll, Susan L. [The Chris O' Brien Lifehouse, Missenden Road, Camperdown, NSW (Australia); Cooper, Caroline L. [Central Clinical School, Sydney Medical School, University of Sydney, NSW (Australia); Department of Tissue Pathology and Diagnostic Oncology, Royal Prince Alfred Hospital, Camperdown, NSW (Australia); Beith, Jane [The Chris O' Brien Lifehouse, Missenden Road, Camperdown, NSW (Australia); McNeil, Catriona [The Kinghorn Cancer Centre & Cancer Research Division, Garvan Institute of Medical Research, Darlinghurst, NSW (Australia); The Chris O' Brien Lifehouse, Missenden Road, Camperdown, NSW (Australia); Carmalt, Hugh; Mak, Cindy; Warrier, Sanjay [The Chris O' Brien Lifehouse, Missenden Road, Camperdown, NSW (Australia); Holliday, Anne [The Kinghorn Cancer Centre & Cancer Research Division, Garvan Institute of Medical Research, Darlinghurst, NSW (Australia); Selinger, Christina; Beckers, Rhiannon [Department of Tissue Pathology and Diagnostic Oncology, Royal Prince Alfred Hospital, Camperdown, NSW (Australia); Kennedy, Catherine [Central Clinical School, Sydney Medical School, University of Sydney, NSW (Australia); Graham, Peter [Department of Radiation Oncology, Cancer Care Centre, St. George Hospital, Kogarah, NSW (Australia); Swarbrick, Alexander [The Kinghorn Cancer Centre & Cancer Research Division, Garvan Institute of Medical Research, Darlinghurst, NSW (Australia); St Vincent' s Clinical School, Faculty of Medicine, University of NSW, Kensington, NSW (Australia); and others

    2015-12-01

    Purpose: Local recurrence and distant failure after adjuvant radiation therapy for breast cancer remain significant clinical problems, incompletely predicted by conventional clinicopathologic markers. We had previously identified microRNA-139-5p and microRNA-1274a as key regulators of breast cancer radiation response in vitro. The purpose of this study was to investigate standard clinicopathologic markers of local recurrence in a contemporary series and to establish whether putative target genes of microRNAs involved in DNA repair and cell cycle control could better predict radiation therapy response in vivo. Methods and Materials: With institutional ethics board approval, local recurrence was measured in a contemporary, prospectively collected series of 458 patients treated with radiation therapy after breast-conserving surgery. Additionally, independent publicly available mRNA/microRNA microarray expression datasets totaling >1000 early-stage breast cancer patients, treated with adjuvant radiation therapy, with >10 years of follow-up, were analyzed. The expression of putative microRNA target biomarkers—TOP2A, POLQ, RAD54L, SKP2, PLK2, and RAG1—were correlated with standard clinicopathologic variables using 2-sided nonparametric tests, and to local/distant relapse and survival using Kaplan-Meier and Cox regression analysis. Results: We found a low rate of isolated local recurrence (1.95%) in our modern series, and that few clinicopathologic variables (such as lymphovascular invasion) were significantly predictive. In multiple independent datasets (n>1000), however, high expression of RAD54L, TOP2A, POLQ, and SKP2 significantly correlated with local recurrence, survival, or both in univariate and multivariate analyses (P<.001). Low RAG1 expression significantly correlated with local recurrence (multivariate, P=.008). Additionally, RAD54L, SKP2, and PLK2 may be predictive, being prognostic in radiation therapy–treated patients but not in untreated matched

  10. Folate deprivation induces cell cycle arrest at G0/G1 phase and apoptosis in hippocampal neuron cells through down-regulation of IGF-1 signaling pathway.

    Science.gov (United States)

    Yang, Yang; Li, Xi; Sun, Qinwei; He, Bin; Jia, Yimin; Cai, Demin; Zhao, Ruqian

    2016-10-01

    Folate deficiency contributes to impaired adult hippocampal neurogenesis, yet the mechanisms remain unclear. Here we use HT-22 hippocampal neuron cells as model to investigate the effect of folate deprivation (FD) on cell proliferation and apoptosis, and to elucidate the underlying mechanism. FD caused cell cycle arrest at G0/G1 phase and increased the rate of apoptosis, which was associated with disrupted expression of folate transport and methyl transfer genes. FOLR1 and SLC46A1 were (Pmethyl transfer pathway and hypermethylation of IGF-1 gene promoter. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Wogonin induced G1 cell cycle arrest by regulating Wnt/β-catenin signaling pathway and inactivating CDK8 in human colorectal cancer carcinoma cells

    International Nuclear Information System (INIS)

    He, Licheng; Lu, Na; Dai, Qinsheng; Zhao, Yue; Zhao, Li; Wang, Hu; Li, Zhiyu; You, Qidong; Guo, Qinglong

    2013-01-01

    Highlights: • Wogonin inhibited HCT116 cells growth and arrested at G1 phase of the cell cycle. • Wogonin down-regulated the canonical Wnt/β-catenin signaling pathway. • Wogonin interfered in the combination of β-catenin and TCF/Lef. • Wogonin limited the kinase activity of CDK8. - Abstract: Wogonin, a naturally occurring mono-flavonoid, has been reported to have tumor therapeutic potential and good selectivity both in vitro and in vivo. Herein, we investigated the anti-proliferation effects and associated mechanisms of wogonin in human colorectal cancer in vitro. The flow-cytometric analysis showed that wogonin induced a G1 phase cell cycle arrest in HCT116 cells in a concentration- and time-dependent manner. Meanwhile, the cell cycle-related proteins, such as cyclin A, E, D1, and CDK2, 4 were down-regulated in wogonin-induced G1 cell cycle arrest. Furthermore, we showed that the anti-proliferation and G1 arrest effect of wogonin on HCT116 cells was associated with deregulation of Wnt/β-catenin signaling pathway. Wogonin-treated cells showed decreased intracellular levels of Wnt proteins, and activated degradation complex to phosphorylated and targeted β-catenin for proteasomal degradation. Wogonin inhibited β-catenin-mediated transcription by interfering in the transcriptional activity of TCF/Lef, and repressing the kinase activity of CDK8 which has been considered as an oncogene involving in the development of colorectal cancers. Moreover, CDK8 siRNA-transfected HCT116 cells showed similar results to wogonin treated cells. Thus, our data suggested that wogonin induced anti-proliferation and G1 arrest via Wnt/β-catenin signaling pathway and it can be developed as a therapeutic agent against human colorectal cancer

  12. An sRNA and Cold Shock Protein Homolog-Based Feedforward Loop Post-transcriptionally Controls Cell Cycle Master Regulator CtrA.

    Science.gov (United States)

    Robledo, Marta; Schlüter, Jan-Philip; Loehr, Lars O; Linne, Uwe; Albaum, Stefan P; Jiménez-Zurdo, José I; Becker, Anke

    2018-01-01

    Adjustment of cell cycle progression is crucial for bacterial survival and adaptation under adverse conditions. However, the understanding of modulation of cell cycle control in response to environmental changes is rather incomplete. In α-proteobacteria, the broadly conserved cell cycle master regulator CtrA underlies multiple levels of control, including coupling of cell cycle and cell differentiation. CtrA levels are known to be tightly controlled through diverse transcriptional and post-translational mechanisms. Here, small RNA (sRNA)-mediated post-transcriptional regulation is uncovered as an additional level of CtrA fine-tuning. Computational predictions as well as transcriptome and proteome studies consistently suggested targeting of ctrA and the putative cold shock chaperone cspA5 mRNAs by the trans- encoded sRNA ( trans- sRNA) GspR (formerly SmelC775) in several Sinorhizobium species. GspR strongly accumulated in the stationary growth phase, especially in minimal medium (MM) cultures. Lack of the gspR locus confers a fitness disadvantage in competition with the wild type, while its overproduction hampers cell growth, suggesting that this riboregulator interferes with cell cycle progression. An eGFP-based reporter in vivo assay, involving wild-type and mutant sRNA and mRNA pairs, experimentally confirmed GspR-dependent post-transcriptional down-regulation of ctrA and cspA5 expression, which most likely occurs through base-pairing to the respective mRNA. The energetically favored secondary structure of GspR is predicted to comprise three stem-loop domains, with stem-loop 1 and stem-loop 3 targeting ctrA and cspA5 mRNA, respectively. Moreover, this work reports evidence for post-transcriptional control of ctrA by CspA5. Thus, this regulation and GspR-mediated post-transcriptional repression of ctrA and cspA5 expression constitute a coherent feed-forward loop, which may enhance the negative effect of GspR on CtrA levels. This novel regulatory circuit involving

  13. Ablation of an Ovarian Tumor Family Deubiquitinase Exposes the Underlying Regulation Governing the Plasticity of Cell Cycle Progression in Toxoplasma gondii.

    Science.gov (United States)

    Dhara, Animesh; de Paula Baptista, Rodrigo; Kissinger, Jessica C; Snow, E Charles; Sinai, Anthony P

    2017-11-21

    The Toxoplasma genome encodes the capacity for distinct architectures underlying cell cycle progression in a life cycle stage-dependent manner. Replication in intermediate hosts occurs by endodyogeny, whereas a hybrid of schizogony and endopolygeny occurs in the gut of the definitive feline host. Here, we characterize the consequence of the loss of a cell cycle-regulated o varian tu mor (OTU family) deubiquitinase, OTUD3A of Toxoplasma gondii (TgOTUD3A; TGGT1_258780), in T. gondii tachyzoites. Rather than the mutation being detrimental, mutant parasites exhibited a fitness advantage, outcompeting the wild type. This phenotype was due to roughly one-third of TgOTUD3A-knockout (TgOTUD3A-KO) tachyzoites exhibiting deviations from endodyogeny by employing replication strategies that produced 3, 4, or 5 viable progeny within a gravid mother instead of the usual 2. We established the mechanistic basis underlying these altered replication strategies to be a dysregulation of centrosome duplication, causing a transient loss of stoichiometry between the inner and outer cores that resulted in a failure to terminate S phase at the attainment of 2N ploidy and/or the decoupling of mitosis and cytokinesis. The resulting dysregulation manifested as deviations in the normal transitions from S phase to mitosis (S/M) (endopolygeny-like) or M phase to cytokinesis (M/C) (schizogony-like). Notably, these imbalances are corrected prior to cytokinesis, resulting in the generation of normal progeny. Our findings suggest that decisions regarding the utilization of specific cell cycle architectures are controlled by a ubiquitin-mediated mechanism that is dependent on the absolute threshold levels of an as-yet-unknown target(s). Analysis of the TgOTUD3A-KO mutant provides new insights into mechanisms underlying the plasticity of apicomplexan cell cycle architecture. IMPORTANCE Replication by Toxoplasma gondii can occur by 3 distinct cell cycle architectures. Endodyogeny is used by asexual

  14. Chloroplast Dysfunction Causes Multiple Defects in Cell Cycle Progression in the Arabidopsis crumpled leaf Mutant

    KAUST Repository

    Hudik, Elodie

    2014-07-18

    The majority of research on cell cycle regulation is focused on the nuclear events that govern the replication and segregation of the genome between the two daughter cells. However, eukaryotic cells contain several compartmentalized organelles with specialized functions, and coordination among these organelles is required for proper cell cycle progression, as evidenced by the isolation of several mutants in which both organelle function and overall plant development were affected. To investigate how chloroplast dysfunction affects the cell cycle, we analyzed the crumpled leaf (crl) mutant of Arabidopsis (Arabidopsis thaliana), which is deficient for a chloroplastic protein and displays particularly severe developmental defects. In the crl mutant, we reveal that cell cycle regulation is altered drastically and that meristematic cells prematurely enter differentiation, leading to reduced plant stature and early endoreduplication in the leaves. This response is due to the repression of several key cell cycle regulators as well as constitutive activation of stress-response genes, among them the cell cycle inhibitor SIAMESE-RELATED5. One unique feature of the crl mutant is that it produces aplastidic cells in several organs, including the root tip. By investigating the consequence of the absence of plastids on cell cycle progression, we showed that nuclear DNA replication occurs in aplastidic cells in the root tip, which opens future research prospects regarding the dialogue between plastids and the nucleus during cell cycle regulation in higher plants.

  15. Over-expression and siRNA of a novel environmental lipopolysaccharide-responding gene on the cell cycle of the human hepatoma-derived cell line HepG2

    International Nuclear Information System (INIS)

    Du Kejun; Chai Yubo; Hou Lichao; Chang Wenhui; Chen Suming; Luo Wenjing; Cai Tongjian; Zhang Xiaonan; Chen Nanchun; Chen Yaoming; Chen Jingyuan

    2008-01-01

    Lipopolysaccharide (LPS) is the toxic determinant for Gram-negative bacterium infection. The individual response to LPS was related to its gene background. It is necessary to identify new molecules and signaling transduction pathways about LPS. The present study was undertaken to evaluate the effects of a novel environmental lipopolysaccharide-responding (Elrg) gene on the regulation of proliferation and cell cycle of the hepatoma-derived cell line, HepG2. By means of RT-PCR, the new molecule of Elrg was generated from a human dental pulp cell cDNA library. Expression level of Elrg in HepG2 cells was remarkably upgraded by the irritation of LPS. Localization of Elrg in HepG2 cells was positioned mainly in cytoplasm. HepG2 cells were markedly arrested in the G1 phase by over-expressing Elrg. The percentage of HepG2 cells in G1 phase partly decreased after Elrg-siRNA. In conclusion, Elrg is probably correlative with LPS responding. Elrg is probably a new protein in cytoplasm which plays an important role in regulating cell cycle. The results will deepen our understanding about the potential effects of Elrg on the human hepatoma-derived cell line HepG2

  16. Antitumor Activity of Tenacissoside H on Esophageal Cancer through Arresting Cell Cycle and Regulating PI3K/Akt-NF-κB Transduction Cascade

    Directory of Open Access Journals (Sweden)

    Yong-sen Jia

    2015-01-01

    Full Text Available Objective. The purpose of the study was to elucidate the molecular mechanism of tenacissoside H (TDH inhibiting esophageal carcinoma infiltration and proliferation. Methods. In vitro, EC9706 cells were treated with TDH. Cells proliferation and cell cycle were assayed. PI3K and NF-κB mRNAs expression were determined by real time PCR. In vivo, model of nude mice with tumor was established. Mice were treated with TDH. Inhibition ratio of tumor volume was calculated. PCNA expression was examined. Protein expression in PI3K/Akt-NF-κB signaling pathway was determined. Results. In vitro, TDH significantly inhibited cells proliferation in a time-and-dose-dependent manner. TDH arrested the cell cycle in S phase and significantly inhibited PI3K and NF-κB mRNA expression, compared with blank controlled group (P<0.05. In vivo, TDH strongly inhibits tumor growth and volume. PCNA expression was significantly decreased after treatment of TDH. TDH downregulated proteins expression in PI3K/Akt-NF-κB transduction cascade (P<0.05. Conclusion. TDH inhibited esophageal carcinoma infiltration and proliferation both in vitro and in vivo. The anticancer activity has relation to arresting the cell cycle at the S phase, inhibited the PCNA expression of transplanted tumors in nude mice, and regulated the protein expression in the PI3K/Akt-NF-κB transduction cascade.

  17. The long non-coding RNA HOTAIR promotes the proliferation of serous ovarian cancer cells through the regulation of cell cycle arrest and apoptosis

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Jun-jun [Department of Gynecology, Obstetrics and Gynecology Hospital, Fudan University, 419 Fangxie Road, Shanghai 200011 (China); Department of Obstetrics and Gynecology of Shanghai Medical College, Fudan University, 138 Yixueyuan Road, Shanghai 200032 (China); Shanghai Key Laboratory of Female Reproductive Endocrine-Related Diseases, 413 Zhaozhou Road, Shanghai 200011 (China); Wang, Yan [Cancer Institute, Fudan University Shanghai Cancer Center, 270 Dong' an Road, Shanghai 200032 (China); Department of Oncology, Shanghai Medical College, Fudan University, 130 Dong' an Road, Shanghai 200032 (China); Ding, Jing-xin; Jin, Hong-yan [Department of Gynecology, Obstetrics and Gynecology Hospital, Fudan University, 419 Fangxie Road, Shanghai 200011 (China); Department of Obstetrics and Gynecology of Shanghai Medical College, Fudan University, 138 Yixueyuan Road, Shanghai 200032 (China); Shanghai Key Laboratory of Female Reproductive Endocrine-Related Diseases, 413 Zhaozhou Road, Shanghai 200011 (China); Yang, Gong, E-mail: yanggong@fudan.edu.cn [Cancer Institute, Fudan University Shanghai Cancer Center, 270 Dong' an Road, Shanghai 200032 (China); Department of Oncology, Shanghai Medical College, Fudan University, 130 Dong' an Road, Shanghai 200032 (China); Hua, Ke-qin, E-mail: huakeqin@126.com [Department of Gynecology, Obstetrics and Gynecology Hospital, Fudan University, 419 Fangxie Road, Shanghai 200011 (China); Department of Obstetrics and Gynecology of Shanghai Medical College, Fudan University, 138 Yixueyuan Road, Shanghai 200032 (China); Shanghai Key Laboratory of Female Reproductive Endocrine-Related Diseases, 413 Zhaozhou Road, Shanghai 200011 (China)

    2015-05-01

    HOX transcript antisense RNA (HOTAIR) is a well-known long non-coding RNA (lncRNA) whose dysregulation correlates with poor prognosis and malignant progression in many forms of cancer. Here, we investigate the expression pattern, clinical significance, and biological function of HOTAIR in serous ovarian cancer (SOC). Clinically, we found that HOTAIR levels were overexpressed in SOC tissues compared with normal controls and that HOTAIR overexpression was correlated with an advanced FIGO stage and a high histological grade. Multivariate analysis revealed that HOTAIR is an independent prognostic factor for predicting overall survival in SOC patients. We demonstrated that HOTAIR silencing inhibited A2780 and OVCA429 SOC cell proliferation in vitro and that the anti-proliferative effects of HOTAIR silencing also occurred in vivo. Further investigation into the mechanisms responsible for the growth inhibitory effects by HOTAIR silencing revealed that its knockdown resulted in the induction of cell cycle arrest and apoptosis through certain cell cycle-related and apoptosis-related proteins. Together, these results highlight a critical role of HOTAIR in SOC cell proliferation and contribute to a better understanding of the importance of dysregulated lncRNAs in SOC progression. - Highlights: • HOTAIR overexpression correlates with an aggressive tumour phenotype and a poor prognosis in SOC. • HOTAIR promotes SOC cell proliferation both in vitro and in vivo. • The proliferative role of HOTAIR is associated with regulation of the cell cycle and apoptosis.

  18. Mechanisms underlying regulation of cell cycle and apoptosis by hnRNP B1 in human lung adenocarcinoma A549 cells.

    Science.gov (United States)

    Han, Juan; Tang, Feng-ming; Pu, Dan; Xu, Dan; Wang, Tao; Li, Weimin

    2014-01-01

    Overexpression of heterogeneous nuclear ribonucleoprotein B1 (hnRNP B1), a nuclear RNA binding protein, has been reported to occur in early-stage lung cancer and in premalignant lesions. DNA-dependent protein kinase (DNA-PK) is known to be involved in the repair of double-strand DNA breaks. Reduced capacity to repair DNA has been associated with the risk of lung cancer. We investigated a link between hnRNP B1 and DNA-PK and their effects on proliferation, cell cycle, and apoptosis in the human lung adenocarcinoma cell line A549. We found that hnRNP B1 and DNA-PK interact with each other in a complex fashion. Reducing hnRNP B1 expression in A549 cells with the use of RNAi led to upregulation of p53 activity through upregulation of DNA-PK activity but without inducing p53 expression. Further, suppression of hnRNP B1 in A549 cells slowed cell proliferation, promoted apoptosis, and induced cell cycle arrest at the G1 stage. The presence of NU7026 reduced the arrest of cells at the G1 stage and reduced the apoptosis rate while promoting cell growth. Taken together, our results demonstrate that by regulating DNA-PK activity, hnRNP B1 can affect p53-mediated cell cycle progression and apoptosis, resulting in greater cell survival and subsequent proliferation.

  19. Overexpression of Zwint predicts poor prognosis and promotes the proliferation of hepatocellular carcinoma by regulating cell-cycle-related proteins

    Directory of Open Access Journals (Sweden)

    Ying H

    2018-02-01

    Full Text Available Hanning Ying,1,2 Zhiyao Xu,3 Mingming Chen,1,2 Senjun Zhou,1,2 Xiao Liang,1,2 Xiujun Cai1,2 1Department of General Surgery, 2Key Laboratory of Endoscopic Technique Research of Zhejiang Province, 3Central Lab of Biomedical Research Center, School of Medicine, Sir Run Run Shaw Hospital, Zhejiang University, Hangzhou, China Introduction: Zwint, a centromere-complex component required for the mitotic spindle checkpoint, has been reported to be overexpressed in different human cancers, but it has not been studied in human hepatocellular carcinoma (HCC.Materials and methods: The role of Zwint in hepatocellular carcinoma cell proliferation capacities was evaluated by using cell counting kit-8 (CCK8, flow cytometry, clone formation and tumor formation assay in nude mice. Western blot analysis and qPCR assay were performed to assess Zwint interacting with cell-cycle-related proteins.Results: We report that ZWINT mRNA and protein expression were upregulated in HCC samples and cell lines. An independent set of 106 HCC-tissue pairs and corresponding noncancerous tissues was evaluated for Zwint expression using immunohistochemistry, and elevated Zwint expression in HCC tissues was significantly correlated with clinicopathological features, such as tumor size and number. Kaplan–Meier survival and Cox regression analysis revealed that high expression of Zwint was correlated with poor overall survival and a greater tendency for tumor recurrence. Ectopic expression of Zwint promoted HCC-cell proliferation, and Zwint expression affected the expression of several cell-cycle proteins, including PCNA, cyclin B1, Cdc25C and CDK1.Conclusion: Our findings suggest that upregulation of Zwint may contribute to the progression of HCC and may be a prognostic biomarker and potential therapeutic target for treating HCC. Keywords: Zwint, hepatocellular carcinoma, HCC, prognosis, cell proliferation, cell cycle

  20. The Concerted Action of Type 2 and Type 3 Deiodinases Regulates the Cell Cycle and Survival of Basal Cell Carcinoma Cells.

    Science.gov (United States)

    Miro, Caterina; Ambrosio, Raffaele; De Stefano, Maria Angela; Di Girolamo, Daniela; Di Cicco, Emery; Cicatiello, Annunziata Gaetana; Mancino, Giuseppina; Porcelli, Tommaso; Raia, Maddalena; Del Vecchio, Luigi; Salvatore, Domenico; Dentice, Monica

    2017-04-01

    Thyroid hormones (THs) mediate pleiotropic cellular processes involved in metabolism, cellular proliferation, and differentiation. The intracellular hormonal environment can be tailored by the type 1 and 2 deiodinase enzymes D2 and D3, which catalyze TH activation and inactivation respectively. In many cellular systems, THs exert well-documented stimulatory or inhibitory effects on cell proliferation; however, the molecular mechanisms by which they control rates of cell cycle progression have not yet been entirely clarified. We previously showed that D3 depletion or TH treatment influences the proliferation and survival of basal cell carcinoma (BCC) cells. Surprisingly, we also found that BCC cells express not only sustained levels of D3 but also robust levels of D2. The aim of the present study was to dissect the contribution of D2 to TH metabolism in the BCC context, and to identify the molecular changes associated with cell proliferation and survival induced by TH and mediated by D2 and D3. We used the CRISPR/Cas9 technology to genetically deplete D2 and D3 in BCC cells and studied the consequences of depletion on cell cycle progression and on cell death. Cell cycle progression was analyzed by fluorescence activated cell sorting analysis of synchronized cells, and the apoptosis rate by annexin V incorporation. Mechanistic investigations revealed that D2 inactivation accelerates cell cycle progression thereby enhancing the proportion of S-phase cells and cyclin D1 expression. Conversely, D3 mutagenesis drastically suppressed cell proliferation and enhanced apoptosis of BCC cells. Furthermore, the basal apoptotic rate was oppositely regulated in D2- and D3-depleted cells. Our results indicate that BCC cells constitute an example in which the TH signal is finely tuned by the concerted expression of opposite-acting deiodinases. The dual regulation of D2 and D3 expression plays a critical role in cell cycle progression and cell death by influencing cyclin D1-mediated

  1. Cell-cycle-dependent localization of human cytomegalovirus UL83 phosphoprotein in the nucleolus and modulation of viral gene expression in human embryo fibroblasts in vitro.

    Science.gov (United States)

    Arcangeletti, Maria-Cristina; Rodighiero, Isabella; Mirandola, Prisco; De Conto, Flora; Covan, Silvia; Germini, Diego; Razin, Sergey; Dettori, Giuseppe; Chezzi, Carlo

    2011-01-01

    The nucleolus is a multifunctional nuclear compartment widely known to be involved in several cellular processes, including mRNA maturation and shuttling to cytoplasmic sites, control of the cell cycle, cell proliferation, and apoptosis; thus, it is logical that many viruses, including herpesvirus, target the nucleolus in order to exploit at least one of the above-mentioned functions. Recent studies from our group demonstrated the early accumulation of the incoming ppUL83 (pp65), the major tegument protein of human cytomegalovirus (HCMV), in the nucleolus. The obtained results also suggested that a functional relationship might exist between the nucleolar localization of pp65, rRNA synthesis, and the development of the lytic program of viral gene expression. Here we present new data which support the hypothesis of a potentially relevant role of HCMV pp65 and its nucleolar localization for the control of the cell cycle by HCMV (arrest of cell proliferation in G1-G1/S), and for the promotion of viral infection. We demonstrated that, although the incoming pp65 amount in the infected cells appears to be constant irrespective of the cell-cycle phase, its nucleolar accumulation is prominent in G1 and G1/S, but very poor in S or G2/M. This correlates with the observation that only cells in G1 and G1/S support an efficient development of the HCMV lytic cycle. We propose that HCMV pp65 might be involved in regulatory/signaling pathways related to nucleolar functions, such as the cell-cycle control. Co-immunoprecipitation experiments have permitted to identify nucleolin as one of the nucleolar partners of pp65.

  2. Dimethylfumarate induces cell cycle arrest and apoptosis via regulating intracellular redox systems in HeLa cells.

    Science.gov (United States)

    Han, Guocan; Zhou, Qiang

    2016-12-01

    Dimethylfumarate (DMF) is cytotoxic to several kinds of cells and serves as an anti-tumor drug. This study was designed to investigate the effects and underlying mechanism of DMF on cervical cancer cells. HeLa cells were cultured and treated with 0, 50, 100, 150, and 200 μM DMF, respectively. After 24 h, cell growth was evaluated using Cell Counting Kit-8 (CCK-8) assay and the cell cycle was examined using flow cytometry. In addition, cell apoptosis was detected by Annexin V/propidium iodide (PI) staining and the expressions of caspase-3 and poly-ADP-ribose polymerase (PARP) were detected using western blotting. The redox-related factors were then assessed. Furthermore, all of the indicators were detected in HeLa cells after combined treatment of DMF and N-acetyl-L-cysteine (NAC, an oxygen-free radical scavenger). The cell number and cell growth of HeLa were obviously inhibited by DMF in a dose-dependent manner, as the cell cycle was arrested at G0/G1 phase (P HeLa cells were markedly increased, and the expression levels of caspase-3 and PARP were significantly increased in a DMF concentration-dependent way (P cell proliferation and apoptosis of HeLa cells was mainly related to the intracellular redox systems by depletion of intracellular GSH.

  3. Improved gene amplification by cell-cycle engineering combined with the Cre-loxP system in Chinese hamster ovary cells.

    Science.gov (United States)

    Matsuyama, Rima; Tsutsui, Tomomi; Lee, Kyoung Ho; Onitsuka, Masayoshi; Omasa, Takeshi

    2015-12-01

    The dihydrofolate reductase gene amplification system is widely used in Chinese hamster ovary (CHO) cells for the industrial production of therapeutic proteins. To enhance the efficiency of conventional gene amplification systems, we previously presented a novel method using cell-cycle checkpoint engineering. Here, we constructed high-producing and stable cells by the conditional expression of mutant cell division cycle 25 homolog B (CDC25B) using the Cre-loxP system. A bispecific antibody-producing CHO DG44-derived cell line was transfected with floxed mutant CDC25B. After inducing gene amplification in the presence of 250 nM methotrexate, mutant CDC25B sequence was removed by Cre recombinase protein expression. Overexpression of the floxed mutant CDC25B significantly enhanced the efficiency of transgene amplification and productivity. Moreover, the specific production rate of the isolated clone CHO Cre-1 and Cre-2 were approximately 11-fold and 15-fold higher than that of mock-transfected clone CHO Mock-S. Chromosomal aneuploidy was increased by mutant CDC25B overexpression, but Cre-1 and Cre-2 did not show any changes in chromosome number during long-term cultivation, as is the case with CHO Mock-S. Our results suggest that high-producing and stable cells can be constructed by conditionally controlling a cell-cycle checkpoint integrated in conventional gene amplification systems. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  4. Analysis of cell cycle regulated and regulating proteins following exposure of lung derived cells to sub-lethal doses of a-rays

    Science.gov (United States)

    Trani, D.; Claudio, P. P.; Cassone, M.; Lucchetti, C.; D'Agostino, L.; Caputi, M.; Giordano, A.

    Introduction Since the last century mankind had to face an increased exposure to man made and natural sources of radiation Radiation represents a therapeutic instrument for radiosensitive cancers as well as a cytotoxic agent for normal human tissues The effects of prolonged exposure to low doses of high energy radiation are still not well-known at the molecular and clinical level Understanding their molecular effects will aid in developing more tailored therapeutic strategies as well as implementing radio-protective measures essential prerequisite for the long-time permanence of men in space Objective of the study The general aim of this study was to evaluate the susceptibility and the response of lung epithelial cells to DNA damage induced by ionizing radiations We decided to study a panel of epithelial bronchial cell lines because of their fast-growth rate and their prominent exposure to both environmental and medical radiations The specific objective of our study was to qualitatively and semi-quantitatively assess the involvement and behaviour of selected genes in DNA damage DNA-repair mechanisms and apoptosis which follow radiation exposure with the aim to determine the involvement of the most promising targets for the early detection of radiation-mediated lung damage before chronic disease develops Methods Four epithelial cell lines one normal and three neoplastic were selected in order to detect and compare survival cell cycle and protein expression differences related to their different genetic asset

  5. Anti-inflammatory drugs suppress proliferation and induce apoptosis through altering expressions of cell cycle regulators and pro-apoptotic factors in cultured human osteoblasts

    International Nuclear Information System (INIS)

    Chang, J.-K.; Li, C.-J.; Liao, H.-J.; Wang, C.-K.; Wang, G.-J.; Ho, M.-L.

    2009-01-01

    It has been reported that anti-inflammatory drugs (AIDs) inhibited bone repair in animal studies, and suppressed proliferation and induced cell death in rat osteoblast cultures. In this study, we further investigated the molecular mechanisms of AID effects on proliferation and cell death in human osteoblasts (hOBs). We examined the effects of dexamethasone (10 -7 and 10 -6 M), non-selective non-steroidal anti-inflammatory drugs (NSAIDs): indomethacin, ketorolac, piroxicam and diclofenac (10 -5 and 10 -4 M), and COX-2 inhibitor: celecoxib (10 -6 and 10 -5 M) on proliferation, cytotoxicity, cell death, and mRNA and protein levels of cell cycle and apoptosis-related regulators in hOBs. All the tested AIDs significantly inhibited proliferation and arrested cell cycle at G0/G1 phase in hOBs. Celecoxib and dexamethasone, but not non-selective NSAIDs, were found to have cytotoxic effects on hOB, and further demonstrated to induce apoptosis and necrosis (at higher concentration) in hOBs. We further found that indomethacin, celecoxib and dexamethasone increased the mRNA and protein expressions of p27 kip1 and decreased those of cyclin D2 and p-cdk2 in hOBs. Bak expression was increased by celecoxib and dexamethasone, while Bcl-XL level was declined only by dexamethasone. Furthermore, the replenishment of PGE1, PGE2 or PGF2α did not reverse the effects of AIDs on proliferation and expressions of p27 kip1 and cyclin D2 in hOBs. We conclude that the changes in expressions of regulators of cell cycle (p27 kip1 and cyclin D2) and/or apoptosis (Bak and Bcl-XL) by AIDs may contribute to AIDs caused proliferation suppression and apoptosis in hOBs. This effect might not relate to the blockage of prostaglandin synthesis by AIDs

  6. ALDH1A1 maintains ovarian cancer stem cell-like properties by altered regulation of cell cycle checkpoint and DNA repair network signaling.

    Directory of Open Access Journals (Sweden)

    Erhong Meng

    Full Text Available OBJECTIVE: Aldehyde dehydrogenase (ALDH expressing cells have been characterized as possessing stem cell-like properties. We evaluated ALDH+ ovarian cancer stem cell-like properties and their role in platinum resistance. METHODS: Isogenic ovarian cancer cell lines for platinum sensitivity (A2780 and platinum resistant (A2780/CP70 as well as ascites from ovarian cancer patients were analyzed for ALDH+ by flow cytometry to determine its association to platinum resistance, recurrence and survival. A stable shRNA knockdown model for ALDH1A1 was utilized to determine its effect on cancer stem cell-like properties, cell cycle checkpoints, and DNA repair mediators. RESULTS: ALDH status directly correlated to platinum resistance in primary ovarian cancer samples obtained from ascites. Patients with ALDHHIGH displayed significantly lower progression free survival than the patients with ALDHLOW cells (9 vs. 3 months, respectively p<0.01. ALDH1A1-knockdown significantly attenuated clonogenic potential, PARP-1 protein levels, and reversed inherent platinum resistance. ALDH1A1-knockdown resulted in dramatic decrease of KLF4 and p21 protein levels thereby leading to S and G2 phase accumulation of cells. Increases in S and G2 cells demonstrated increased expression of replication stress associated Fanconi Anemia DNA repair proteins (FANCD2, FANCJ and replication checkpoint (pS317 Chk1 were affected. ALDH1A1-knockdown induced DNA damage, evidenced by robust induction of γ-H2AX and BAX mediated apoptosis, with significant increases in BRCA1 expression, suggesting ALDH1A1-dependent regulation of cell cycle checkpoints and DNA repair networks in ovarian cancer stem-like cells. CONCLUSION: This data suggests that ovarian cancer cells expressing ALDH1A1 may maintain platinum resistance by altered regulation of cell cycle checkpoint and DNA repair network signaling.

  7. Immunohistochemical analyses of cell cycle progression and gene expression of biliary epithelial cells during liver regeneration after partial hepatectomy of the mouse.

    Science.gov (United States)

    Fukuda, Tatsuya; Fukuchi, Tomokazu; Yagi, Shinomi; Shiojiri, Nobuyoshi

    2016-05-20

    The liver has a remarkable regeneration capacity, and, after surgical removal of its mass, the remaining tissue undergoes rapid regeneration through compensatory growth of its constituent cells. Although hepatocytes synchronously proliferate under the control of various signaling molecules from neighboring cells, there have been few detailed analyses on how biliary cells regenerate for their cell population after liver resection. The present study was undertaken to clarify how biliary cells regenerate after partial hepatectomy of mice through extensive analyses of their cell cycle progression and gene expression using immunohistochemical and RT-PCR techniques. When expression of PCNA, Ki67 antigen, topoisomerase IIα and phosphorylated histone H3, which are cell cycle markers, was immunohistochemically examined during liver regeneration, hepatocytes had a peak of the S phase and M phase at 48-72 h after resection. By contrast, biliary epithelial cells had much lower proliferative activity than that of hepatocytes, and their peak of the S phase was delayed. Mitotic figures were rarely detectable in biliary cells. RT-PCR analyses of gene expression of biliary markers such as Spp1 (osteopontin), Epcam and Hnf1b demonstrated that they were upregulated during liver regeneration. Periportal hepatocytes expressed some of biliary markers, including Spp1 mRNA and protein. Some periportal hepatocytes had downregulated expression of HNF4α and HNF1α. Gene expression of Notch signaling molecules responsible for cell fate decision of hepatoblasts to biliary cells during development was upregulated during liver regeneration. Notch signaling may be involved in biliary regeneration.

  8. GLI1 is involved in cell cycle regulation and proliferation of NT2 embryonal carcinoma stem cells

    DEFF Research Database (Denmark)

    Vestergaard, Janni; Lind-Thomsen, Allan; Pedersen, Mikkel W.

    2008-01-01

    of altered HH signaling are interpreted by specific cell types. We have investigated the role of the HH transcription factor glioma-associated oncogene homolog 1 (GLI1) in the human Ntera2=D1 (NT2) embryonal carcinoma stem cell line. The study revealed that expression of GLI1 and its direct transcriptional......1 phase cyclins. In conclusion, our results suggest that GLI1 is involved in cell cycle and proliferation control in the embryonal carcinoma stem cell line NT2....... target Patched (PTCH) is downregulated in the early stages of retinoic acid-induced neuronal differentiation of NT2 cells. To identify transcriptional targets of the HH transcription factor GLI1 in NT2 cells, we performed global expression profiling following GLI1 RNA interference (RNAi). Of the similar...

  9. Cell cycle- and cell growth-regulated proteolysis of mammalian CDC6 is dependent on APC-CDH1

    DEFF Research Database (Denmark)

    Petersen, B O; Wagener, C; Marinoni, F

    2000-01-01

    is targeted for ubiquitin-mediated proteolysis by the anaphase promoting complex (APC)/cyclosome in G(1). A combination of point mutations in the destruction box and KEN-box motifs in CDC6 stabilizes the protein in G(1) and in quiescent cells. Furthermore, APC, in association with CDH1, ubiquitinates CDC6...... in vitro, and both APC and CDH1 are required and limiting for CDC6 proteolysis in vivo. Although a stable mutant of CDC6 is biologically active, overexpression of this mutant or wild-type CDC6 is not sufficient to induce multiple rounds of DNA replication in the same cell cycle. The APC-CDH1-dependent...

  10. Pim-3 contributes to radioresistance through regulation of the cell cycle and DNA damage repair in pancreatic cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xiang-Yuan; Wang, Zhen [Cancer Research Institute, Fudan University Shanghai Cancer Center, Department of Oncology, Shanghai Medical College, Fudan University, Shanghai (China); Li, Bei [Department of Nuclear Medicine, Fudan University Shanghai Cancer Center, Department of Oncology, Shanghai Medical College, Fudan University, Shanghai (China); Zhang, Ying-Jian, E-mail: yjzhang111@aliyun.com [Department of Nuclear Medicine, Fudan University Shanghai Cancer Center, Department of Oncology, Shanghai Medical College, Fudan University, Shanghai (China); Li, Ying-Yi, E-mail: liyingyi@fudan.edu.cn [Cancer Research Institute, Fudan University Shanghai Cancer Center, Department of Oncology, Shanghai Medical College, Fudan University, Shanghai (China)

    2016-04-22

    Resistance of cancer cells to chemoradiotherapy is a major clinical problem in pancreatic cancer treatment. Therefore, understanding the molecular basis of cellular resistance and identifying novel targets are essential for improving treatment efficacy for pancreatic cancer patients. Previous studies have demonstrated a significant role for Pim-3 in pancreatic cancer survival against gemcitabine-induced genotoxic stress. Here, we observed that radiation treatment enhanced Pim-3 expression in human pancreatic cancer cells in vitro. Stable overexpression of Pim-3 in pancreatic cancer cells significantly protected cells against radiation treatment by attenuating G2/M phase cell cycle arrest and DNA damage response. Silencing of Pim-3 expression significantly elevated the phosphorylation of histone variant H2AX, a marker of DNA double strand breaks, and decreased the activation of ataxia-telangiectasia-mutated (ATM) kinase, along with its downstream targets, eventually enhancing the radiosensitivity of human pancreatic cancer cells in vitro and in vivo. Hence, we demonstrated a novel function for Pim-3 in human pancreatic cancer cell survival against radiation. Targeting Pim-3 may be a promising way to improve treatment efficacy in combination with radiotherapy in human pancreatic cancer. - Highlights: • This is first study to demonstrate that Pim-3 is endogenously induced by ionizing radiation in pancreatic cancer cells, and Pim-3 overexpression enhanced radioresistance of pancreatic cancer cells both in vitro and in vivo. • This is first study to provide evidence that radioresistance induced by Pim-3 is mainly attributed to Pim-3 induces activation of ATM, which subsequently activates checkpoint 1, leading to amplification of DNA repair through cell cycle arrest and DNA repair pathways. • This is first study to indicate that targeting Pim-3 may be a promising strategy to provide better treatment efficacy in combination with radiotherapy in human pancreatic

  11. Cadmium promotes the proliferation of triple-negative breast cancer cells through EGFR-mediated cell cycle regulation

    International Nuclear Information System (INIS)

    Wei, Zhengxi; Song, Xiulong; Shaikh, Zahir A.

    2015-01-01

    Cadmium (Cd) is a carcinogenic metal which is implicated in breast cancer by epidemiological studies. It is reported to promote breast cancer cell growth in vitro through membrane receptors. The study described here examined Cd-mediated growth of non-metastatic human breast cancer derived cells that lack receptors for estrogen, progesterone, and HER2. Treatment of triple-negative HCC 1937 cells with 0.1–0.5 μM Cd increased cell growth by activation of AKT and ERK. Accelerated cell cycle progression was achieved by increasing the levels of cyclins A, B, and E, as well as those of CDKs 1 and 2. Although triple negative cells lack estrogen receptor, they express high levels of EGFR. Therefore, further studies on HCC 1937 and another triple-negative cell line, HCC 38, were conducted using specific siRNA and an inhibitor of EGFR to determine whether EGFR was responsible for mediating the effect of Cd. The results revealed that in both cell types EGFR was not only activated upon Cd treatment, but was also essential for the downstream activation of AKT and ERK. Based on these observations, it is concluded that, in breast cancer cells lacking estrogen receptor, sub-micromolar concentration of Cd can promote cell proliferation. Furthermore, that EGFR plays a critical role in this process. - Highlights: • Sub-micromolar concentrations of Cd promote cell growth in breast cancer cells that lack ER, PR, and HER2. • The increase in cell number is not due to reduction in apoptosis. • Growth promotion involves AKT and ERK signaling and downstream stimulation of cell cycle progression. • Initiation of cell growth by Cd occurs at the cell membrane and requires the activation of EGFR.

  12. Pim-3 contributes to radioresistance through regulation of the cell cycle and DNA damage repair in pancreatic cancer cells

    International Nuclear Information System (INIS)

    Chen, Xiang-Yuan; Wang, Zhen; Li, Bei; Zhang, Ying-Jian; Li, Ying-Yi

    2016-01-01

    Resistance of cancer cells to chemoradiotherapy is a major clinical problem in pancreatic cancer treatment. Therefore, understanding the molecular basis of cellular resistance and identifying novel targets are essential for improving treatment efficacy for pancreatic cancer patients. Previous studies have demonstrated a significant role for Pim-3 in pancreatic cancer survival against gemcitabine-induced genotoxic stress. Here, we observed that radiation treatment enhanced Pim-3 expression in human pancreatic cancer cells in vitro. Stable overexpression of Pim-3 in pancreatic cancer cells significantly protected cells against radiation treatment by attenuating G2/M phase cell cycle arrest and DNA damage response. Silencing of Pim-3 expression significantly elevated the phosphorylation of histone variant H2AX, a marker of DNA double strand breaks, and decreased the activation of ataxia-telangiectasia-mutated (ATM) kinase, along with its downstream targets, eventually enhancing the radiosensitivity of human pancreatic cancer cells in vitro and in vivo. Hence, we demonstrated a novel function for Pim-3 in human pancreatic cancer cell survival against radiation. Targeting Pim-3 may be a promising way to improve treatment efficacy in combination with radiotherapy in human pancreatic cancer. - Highlights: • This is first study to demonstrate that Pim-3 is endogenously induced by ionizing radiation in pancreatic cancer cells, and Pim-3 overexpression enhanced radioresistance of pancreatic cancer cells both in vitro and in vivo. • This is first study to provide evidence that radioresistance induced by Pim-3 is mainly attributed to Pim-3 induces activation of ATM, which subsequently activates checkpoint 1, leading to amplification of DNA repair through cell cycle arrest and DNA repair pathways. • This is first study to indicate that targeting Pim-3 may be a promising strategy to provide better treatment efficacy in combination with radiotherapy in human pancreatic

  13. A signature-based method for indexing cell cycle phase distribution from microarray profiles

    Directory of Open Access Journals (Sweden)

    Mizuno Hideaki

    2009-03-01

    Full Text Available Abstract Background The cell cycle machinery interprets oncogenic signals and reflects the biology of cancers. To date, various methods for cell cycle phase estimation such as mitotic index, S phase fraction, and immunohistochemistry have provided valuable information on cancers (e.g. proliferation rate. However, those methods rely on one or few measurements and the scope of the information is limited. There is a need for more systematic cell cycle analysis methods. Results We developed a signature-based method for indexing cell cycle phase distribution from microarray profiles under consideration of cycling and non-cycling cells. A cell cycle signature masterset, composed of genes which express preferentially in cycling cells and in a cell cycle-regulated manner, was created to index the proportion of cycling cells in the sample. Cell cycle signature subsets, composed of genes whose expressions peak at specific stages of the cell cycle, were also created to index the proportion of cells in the corresponding stages. The method was validated using cell cycle datasets and quiescence-induced cell datasets. Analyses of a mouse tumor model dataset and human breast cancer datasets revealed variations in the proportion of cycling cells. When the influence of non-cycling cells was taken into account, "buried" cell cycle phase distributions were depicted that were oncogenic-event specific in the mouse tumor model dataset and were associated with patients' prognosis in the human breast cancer datasets. Conclusion The signature-based cell cycle analysis method presented in this report, would potentially be of value for cancer characterization and diagnostics.

  14. An Ingenol Derived from Euphorbia kansui Induces Hepatocyte Cytotoxicity by Triggering G0/G1 Cell Cycle Arrest and Regulating the Mitochondrial Apoptosis Pathway in Vitro

    Directory of Open Access Journals (Sweden)

    Xiaojing Yan

    2016-06-01

    Full Text Available Natural product lingenol, a purified diterpenoid compound derived from the root of Euphorbia kansui, exerts serious hepatotoxicity; however, the molecular mechanisms remain to be defined. In the present study, cell counting Kit-8 (CCK-8, inverted phase contrast microscope and flow cytometry were used to demonstrate that lingenol significantly inhibited L-O2 cells proliferation, and induced cell cycle arrest and apoptosis. Moreover, the results investigated that lingenol markedly disrupted mitochondrial functions by high content screening (HCS. In addition, the up-regulation of cytochrome c, AIF and Apaf-1 and activation of caspases were found in L-O2 cells detected by Western blotting and ELISA assay, which was required for lingenol activation of cytochrome c-mediated caspase cascades and AIF-mediated DNA damage. Mechanistic investigations revealed that lingenol significantly down-regulated the Bcl-2/Bax ratio and enhanced the reactive oxygen species (ROS in L-O2 cells. These data collectively indicated that lingenol modulation of ROS and Bcl-2/Bax ratio led to cell cycle arrest and mitochondrial-mediated apoptosis in L-O2 cells in vitro. All of these results will be helpful to reveal the hepatotoxicity mechanism of Euphorbia kansui and to effectively guide safer and better clinical application of this herb.

  15. The KRAB Zinc Finger Protein Roma/Zfp157 Is a Critical Regulator of Cell-Cycle Progression and Genomic Stability

    Directory of Open Access Journals (Sweden)

    Teresa L.F. Ho

    2016-04-01

    Full Text Available Regulation of DNA replication and cell division is essential for tissue growth and maintenance of genomic integrity and is particularly important in tissues that undergo continuous regeneration such as mammary glands. We have previously shown that disruption of the KRAB-domain zinc finger protein Roma/Zfp157 results in hyperproliferation of mammary epithelial cells (MECs during pregnancy. Here, we delineate the mechanism by which Roma engenders this phenotype. Ablation of Roma in MECs leads to unscheduled proliferation, replication stress, DNA damage, and genomic instability. Furthermore, mouse embryonic fibroblasts (MEFs depleted for Roma exhibit downregulation of p21Cip1 and geminin and have accelerated replication fork velocities, which is accompanied by a high rate of mitotic errors and polyploidy. In contrast, overexpression of Roma in MECs halts cell-cycle progression, whereas siRNA-mediated p21Cip1 knockdown ameliorates, in part, this phenotype. Thus, Roma is an essential regulator of the cell cycle and is required to maintain genomic stability.

  16. Molecular signature of cell cycle exit induced in human T lymphoblasts by IL-2 withdrawal

    Directory of Open Access Journals (Sweden)

    Pfeifer Aleksandra

    2009-06-01

    Full Text Available Abstract Background The molecular mechanisms of cell cycle exit are poorly understood. Studies on lymphocytes at cell cycle exit after growth factor deprivation have predominantly focused on the initiation of apoptosis. We aimed to study gene expression profile of primary and immortalised IL-2-dependent human T cells forced to exit the cell cycle by growth factor withdrawal, before apoptosis could be evidenced. Results By the Affymetrix microarrays HG-U133 2.0 Plus, 53 genes were distinguished as differentially expressed before and soon after IL-2 deprivation. Among those, PIM1, BCL2, IL-8, HBEGF, DUSP6, OSM, CISH, SOCS2, SOCS3, LIF and IL13 were down-regulated and RPS24, SQSTM1, TMEM1, LRRC8D, ECOP, YY1AP1, C1orf63, ASAH1, SLC25A46 and MIA3 were up-regulated. Genes linked to transcription, cell cycle, cell growth, proliferation and differentiation, cell adhesion, and immune functions were found to be overrepresented within the set of the differentially expressed genes. Conclusion Cell cycle exit of the growth factor-deprived T lymphocytes is characterised by a signature of differentially expressed genes. A coordinate repression of a set of genes known to be induced during T cell activation is observed. However, growth arrest following exit from the cell cycle is actively controlled by several up-regulated genes that enforce the non-dividing state. The identification of genes involved in cell cycle exit and quiescence provides new hints for further studies on the molecular mechanisms regulating the non-dividing state of a cell, the mechanisms closely related to cancer development and to many biological processes.

  17. Tax gene expression and cell cycling but not cell death are selected during HTLV-1 infection in vivo

    Directory of Open Access Journals (Sweden)

    Pinatel Christiane

    2010-03-01

    Full Text Available Abstract Background Adult T cell leukemia results from the malignant transformation of a CD4+ lymphoid clone carrying an integrated HTLV-1 provirus that has undergone several oncogenic events over a 30-60 year period of persistent clonal expansion. Both CD4+ and CD8+ lymphocytes are infected in vivo; their expansion relies on CD4+ cell cycling and on the prevention of CD8+ cell death. Cloned infected CD4+ but not CD8+ T cells from patients without malignancy also add up nuclear and mitotic defects typical of genetic instability related to theexpression of the virus-encoded oncogene tax. HTLV-1 expression is cancer-prone in vitro, but in vivo numerous selection forces act to maintain T cell homeostasis and are possibly involved in clonal selection. Results Here we demonstrate that the HTLV-1 associated CD4+ preleukemic phenotype and the specific patterns of CD4+ and CD8+ clonal expansion are in vivo selected processes. By comparing the effects of recent (1 month experimental infections performed in vitro and those observed in cloned T cells from patients infected for >6-26 years, we found that in chronically HTLV-1 infected individuals, HTLV-1 positive clones are selected for tax expression. In vivo, infected CD4+ cells are positively selected for cell cycling whereas infected CD8+ cells and uninfected CD4+ cells are negatively selected for the same processes. In contrast, the known HTLV-1-dependent prevention of CD8+ T cell death pertains to both in vivo and in vitro infected cells. Conclusions Therefore, virus-cell interactions alone are not sufficient to initiate early leukemogenesis in vivo.

  18. The cucurbitacins D, E, and I from Ecballium elaterium (L. upregulate the LC3 gene and induce cell-cycle arrest in human gastric cancer cell line AGS

    Directory of Open Access Journals (Sweden)

    Naser Jafargholizadeh

    2018-03-01

    Full Text Available Objective(s: Cucurbitacins exhibit a range of anti-cancer functions. We investigated the effects of cucurbitacins D, E, and I purified from Ecballium elaterium (L. A. Rich fruits on some apoptotic and autophagy genes in human gastric cancer cell line AGS. Materials and Methods: Using quantitative reverse transcription PCR (qRT-PCR, the expression of LC3, VEGF, BAX, caspase-3, and c-MYC genes were quantified in AGS cells 24 hr after treatment with cucurbitacins D, E, and I at concentrations 0.3, 0.1 and 0.5 μg/ml, respectively. Cell cycle and death were analyzed by flowcytometry. Results: Purified cucurbitacins induced sub-G1 cell-cycle arrest and cell death in AGS cells and upregulated LC3mRNA effectively, but showed a very low effect on BAX, caspase-3, and c-MYC mRNA levels. Also after treatment with cucurbitacin I at concentration 0.5 μg/ml, VEGF mRNA levels were increased about 4.4 times. Pairwise comparison of the effect of cucurbitacins D, E, and I on LC3 mRNA expression showed that the cucurbitacin I effect is 1.3 and 1.1 times that of cucurbitacins E and D, respectively; cucurbitacin D effect is 1.2 times that of cucurbitacin E (P-value

  19. Cyclin A regulates a cell-cycle-dependent expression of CKAP2 through phosphorylation of Sp1

    International Nuclear Information System (INIS)

    Kang, Du-Seock; Hong, Kyeong-Man; Park, Joobae; Bae, Chang-Dae

    2012-01-01

    Highlights: ► We identified a GC box and a CHR element in human CKAP2 minimal promoter. ► The CHR element repressed the CKAP2 minimal promoter activity at the G1/S phase. ► The GC box was essential for the basic promoter activity of human CKAP2. ► The GC box was also essential for the cyclic expression of human CKAP2. ► The phosphorylation of Sp1, mediated by Cyclin A, underlies the cyclic expression. -- Abstract: CKAP2 plays crucial roles in proper chromosome segregation and maintaining genomic stability. CKAP2 protein showed cell-cycle-dependent expression, which reached a maximum level at the G2/M phase and disappeared at the onset of G1 phase. To elucidate the mechanisms underlying cell cycle-dependent expression of CKAP2, we cloned and analyzed the human CKAP2 promoter. The upstream 115-bp region from the transcription start site was sufficient for minimal CKAP2 promoter activity. We identified 2 regulatory sequences; a CHR (−110 to −104 bp) and a GC box (−41 to −32 bp). We confirmed Sp1 bound to the GC box using a supershift assay and a ChIP assay. Mutation in the GC box resulted in a near complete loss of CKAP2 promoter activity while mutation in the CHR decreased the promoter activity by 50%. The CHR mutation showed enhanced activity at the G1/S phase, but still retained cyclic activity. The Chromatin IP revealed that the amount of Sp1 bound to the GC box gradually increased and reached a maximum level at the G2/M phase. The amount of Sp1 bound to the GC box was greatly reduced when Cyclin A was depleted, which was restored by adding Cyclin A/Cdk2 complex back into the nuclear extracts. Together, we concluded that the GC box was responsible for the cyclic activity of human CKAP2 promoter through the phosphorylation of Sp1, possibly by Cyclin A/Cdk complex.

  20. Cell Cycle Regulating Kinase Cdk4 as a Potential Target for Tumor Cell Treatment and Tumor Imaging

    Directory of Open Access Journals (Sweden)

    Franziska Graf

    2009-01-01

    Full Text Available The cyclin-dependent kinase (Cdk-cyclin D/retinoblastoma (pRb/E2F cascade, which controls the G1/S transition of cell cycle, has been found to be altered in many neoplasias. Inhibition of this pathway by using, for example, selective Cdk4 inhibitors has been suggested to be a promising approach for cancer therapy. We hypothesized that appropriately radiolabeled Cdk4 inhibitors are suitable probes for tumor imaging and may be helpful studying cell proliferation processes in vivo by positron emission tomography. Herein, we report the synthesis and biological, biochemical, and radiopharmacological characterizations of two I124-labeled small molecule Cdk4 inhibitors (8-cyclopentyl-6-iodo-5-methyl-2-(4-piperazin-1-yl-phenylamino-8H-pyrido[2,3-d]-pyrimidin-7-one (CKIA and 8-cyclopentyl-6-iodo-5-methyl-2-(5-(piperazin-1-yl-pyridin-2-yl-amino-8H-pyrido[2,3-d]pyrimidin-7-one (CKIB. Our data demonstrate a defined and specific inhibition of tumor cell proliferation through CKIA and CKIB by inhibition of the Cdk4/pRb/E2F pathway emphasizing potential therapeutic benefit of CKIA and CKIB. Furthermore, radiopharmacological properties of [I124]CKIA and [I124]CKIB observed in human tumor cells are promising prerequisites for in vivo biodistribution and imaging studies.

  1. Phytometabolite Dehydroleucodine Induces Cell Cycle Arrest, Apoptosis, and DNA Damage in Human Astrocytoma Cells through p73/p53 Regulation.

    Directory of Open Access Journals (Sweden)

    Natalia Bailon-Moscoso

    Full Text Available Accumulating evidence supports the idea that secondary metabolites obtained from medicinal plants (phytometabolites may be important contributors in the development of new chemotherapeutic agents to reduce the occurrence or recurrence of cancer. Our study focused on Dehydroleucodine (DhL, a sesquiterpene found in the provinces of Loja and Zamora-Chinchipe. In this study, we showed that DhL displayed cytostatic and cytotoxic activities on the human cerebral astrocytoma D384 cell line. With lactone isolated from Gynoxys verrucosa Wedd, a medicinal plant from Ecuador, we found that DhL induced cell death in D384 cells by triggering cell cycle arrest and inducing apoptosis and DNA damage. We further found that the cell death resulted in the increased expression of CDKN1A and BAX proteins. A marked induction of the levels of total TP73 and phosphorylated TP53, TP73, and γ-H2AX proteins was observed in D384 cells exposed to DhL, but no increase in total TP53 levels was detected. Overall these studies demonstrated the marked effect of DhL on the diminished survival of human astrocytoma cells through the induced expression of TP73 and phosphorylation of TP73 and TP53, suggesting their key roles in the tumor cell response to DhL treatment.

  2. Phytometabolite Dehydroleucodine Induces Cell Cycle Arrest, Apoptosis, and DNA Damage in Human Astrocytoma Cells through p73/p53 Regulation.

    Science.gov (United States)

    Bailon-Moscoso, Natalia; González-Arévalo, Gabriela; Velásquez-Rojas, Gabriela; Malagon, Omar; Vidari, Giovanni; Zentella-Dehesa, Alejandro; Ratovitski, Edward A; Ostrosky-Wegman, Patricia

    2015-01-01

    Accumulating evidence supports the idea that secondary metabolites obtained from medicinal plants (phytometabolites) may be important contributors in the development of new chemotherapeutic agents to reduce the occurrence or recurrence of cancer. Our study focused on Dehydroleucodine (DhL), a sesquiterpene found in the provinces of Loja and Zamora-Chinchipe. In this study, we showed that DhL displayed cytostatic and cytotoxic activities on the human cerebral astrocytoma D384 cell line. With lactone isolated from Gynoxys verrucosa Wedd, a medicinal plant from Ecuador, we found that DhL induced cell death in D384 cells by triggering cell cycle arrest and inducing apoptosis and DNA damage. We further found that the cell death resulted in the increased expression of CDKN1A and BAX proteins. A marked induction of the levels of total TP73 and phosphorylated TP53, TP73, and γ-H2AX proteins was observed in D384 cells exposed to DhL, but no increase in total TP53 levels was detected. Overall these studies demonstrated the marked effect of DhL on the diminished survival of human astrocytoma cells through the induced expression of TP73 and phosphorylation of TP73 and TP53, suggesting their key roles in the tumor cell response to DhL treatment.

  3. Enrichment of G2/M cell cycle phase in human pluripotent stem cells enhances HDR-mediated gene repair with customizable endonucleases.

    Science.gov (United States)

    Yang, Diane; Scavuzzo, Marissa A; Chmielowiec, Jolanta; Sharp, Robert; Bajic, Aleksandar; Borowiak, Malgorzata

    2016-02-18

    Efficient gene editing is essential to fully utilize human pluripotent stem cells (hPSCs) in regenerative medicine. Custom endonuclease-based gene targeting involves two mechanisms of DNA repair: homology directed repair (HDR) and non-homologous end joining (NHEJ). HDR is the preferred mechanism for common applications such knock-in, knock-out or precise mutagenesis, but remains inefficient in hPSCs. Here, we demonstrate that synchronizing synchronizing hPSCs in G2/M with ABT phase increases on-target gene editing, defined as correct targeting cassette integration, 3 to 6 fold. We observed improved efficiency using ZFNs, TALENs, two CRISPR/Cas9, and CRISPR/Cas9 nickase to target five genes in three hPSC lines: three human embryonic stem cell lines, neural progenitors and diabetic iPSCs. neural progenitors and diabetic iPSCs. Reversible synchronization has no effect on pluripotency or differentiation. The increase in on-target gene editing is locus-independent and specific to the cell cycle phase as G2/M phase enriched cells show a 6-fold increase in targeting efficiency compared to cells in G1 phase. Concurrently inhibiting NHEJ with SCR7 does not increase HDR or improve gene targeting efficiency further, indicating that HR is the major DNA repair mechanism after G2/M phase arrest. The approach outlined here makes gene editing in hPSCs a more viable tool for disease modeling, regenerative medicine and cell-based therapies.

  4. Treatment with bisphenol A and methoxychlor results in the growth of human breast cancer cells and alteration of the expression of cell cycle-related genes, cyclin D1 and p21, via an estrogen receptor-dependent signaling pathway.

    Science.gov (United States)

    Lee, Hye-Rim; Hwang, Kyung-A; Park, Min-Ah; Yi, Bo-Rim; Jeung, Eui-Bae; Choi, Kyung-Chul

    2012-05-01

    Various endocrine disrupting chemicals (EDCs) are exogenous compounds found in the environment and have the potential to interfere with the endocrine system and hormonal regulation. Among EDCs, bisphenol A (BPA) and 1,1,1-trichloro-2,2-bis(4-methoxyphenol)-ethane [methoxychlor (MXC)] have estrogenic activity resulting in a variety of dysfunctions in the E2-mediated response by binding to estrogen receptors (ERs), causing human health problems such as abnormal reproduction and carcinogenesis. In this study, we investigated the effects of BPA and MXC on cell proliferation facilitated by ER signaling in human breast cancer cells. MCF-7 cells are known to be ERα-positive and to be a highly E2-responsive cancer cell line; these cells are, therefore, a useful in vitro model for detecting estrogenic activity in response to EDCs. We evaluated cancer cell proliferation following BPA and MXC treatment using an MTT assay. We analyzed alterations in the expression of genes associated with the cell cycle in MCF-7 cells by semi-quantitative reverse-transcription PCR following treatment with BPA or MXC compared to EtOH. To determine whether BPA and MXC stimulate cancer cell growth though ER signaling, we co-treated the cells with agonists (propyl pyrazoletriol, PPT; and diarylpropionitrile, DPN) or an antagonist (ICI 182,780) of ER signaling and reduced ERα gene expression via siRNA in MCF-7 cells before treatment with EDCs. These studies confirmed the carcinogenicity of EDCs in vitro. As a result, BPA and MXC induced the cancer cell proliferation by the upregulation of genes that promote the cell cycle and the downregulation of anti-proliferative genes, especially ones affecting the G1/S transition via ERα signaling. These collective results confirm the carcinogenicity of these EDCs in vitro. Further studies are required to determine whether EDCs promote carcinogenesis in vivo.

  5. Mel-18 negatively regulates INK4a/ARF-independent cell cycle progression via Akt inactivation in breast cancer.

    Science.gov (United States)

    Lee, Jeong-Yeon; Jang, Ki-Seok; Shin, Dong-Hui; Oh, Mi-Yun; Kim, Hyun-Jun; Kim, Yongseok; Kong, Gu

    2008-06-01

    Mel-18, a polycomb group (PcG) protein, has been suggested as a tumor suppressor in human breast cancer. Previously, we reported that Mel-18 has antiproliferative activity in breast cancer cells. However, its functional mechanism has not been fully elucidated. Here, we investigated the role of Mel-18 in human breast cancer. We saw an inverse correlation between Mel-18 and phospho-Akt, which were expressed at low and high levels, respectively, in primary breast tumor tissues from 40 breast cancer patients. The effect of Mel-18 on cell growth was examined in two breast cancer cell lines, SK-BR-3 and T-47D, which express relatively low and high levels of endogenous Mel-18, respectively. On Mel-18 overexpression in SK-BR-3 cells, cell growth was attenuated and G(1) arrest was observed. Likewise, suppression of Mel-18 by antisense expression in T-47D cells led to enhanced cell growth and accelerated G(1)-S phase transition. In these cells, cyclin-dependent kinase (Cdk)-4 and Cdk2 activities were affected by Mel-18, which were mediated by changes in cyclin D1 expression and p27(Kip1) phosphorylation at Thr(157), but not by INK4a/ARF genes. The changes were both dependent on the phosphatidylinositol 3-kinase/Akt signaling pathway. Akt phosphorylation at Ser(473) was reduced by Mel-18 overexpression in SK-BR-3 cells and enhanced by Mel-18 suppression in T-47D cells. Akt-mediated cytoplasmic localization of p27(Kip1) was inhibited by Mel-18 in SK-BR-3 cells. Moreover, Mel-18 overexpression showed reduced glycogen synthase kinase-3beta phosphorylation, beta-catenin nuclear localization, T-cell factor/lymphoid enhancer factor promoter activity, and cyclin D1 mRNA level. Taken together, we established a linear relationship between Mel-18-->Akt-->G(1) phase regulators.

  6. TGEV nucleocapsid protein induces cell cycle arrest and apoptosis through activation of p53 signaling

    International Nuclear Information System (INIS)

    Ding, Li; Huang, Yong; Du, Qian; Dong, Feng; Zhao, Xiaomin; Zhang, Wenlong; Xu, Xingang; Tong, Dewen

    2014-01-01

    Highlights: • TGEV N protein reduces cell viability by inducing cell cycle arrest and apoptosis. • TGEV N protein induces cell cycle arrest and apoptosis by regulating p53 signaling. • TGEV N protein plays important roles in TGEV-induced cell cycle arrest and apoptosis. - Abstract: Our previous studies showed that TGEV infection could induce cell cycle arrest and apoptosis via activation of p53 signaling in cultured host cells. However, it is unclear which viral gene causes these effects. In this study, we investigated the effects of TGEV nucleocapsid (N) protein on PK-15 cells. We found that TGEV N protein suppressed cell proliferation by causing cell cycle arrest at the S and G2/M phases and apoptosis. Characterization of various cellular proteins that are involved in regulating cell cycle progression demonstrated that the expression of N gene resulted in an accumulation of p53 and p21, which suppressed cyclin B1, cdc2 and cdk2 expression. Moreover, the expression of TGEV N gene promoted translocation of Bax to mitochondria, which in turn caused the release of cytochrome c, followed by activation of caspase-3, resulting in cell apoptosis in the transfected PK-15 cells following cell cycle arrest. Further studies showed that p53 inhibitor attenuated TGEV N protein induced cell cycle arrest at S and G2/M phases and apoptosis through reversing the expression changes of cdc2, cdk2 and cyclin B1 and the translocation changes of Bax and cytochrome c induced by TGEV N protein. Taken together, these results demonstrated that TGEV N protein might play an important role in TGEV infection-induced p53 activation and cell cycle arrest at the S and G2/M phases and apoptosis occurrence

  7. Mutation analysis of genes that control the G1/S cell cycle in melanoma: TP53, CDKN1A, CDKN2A, and CDKN2B

    International Nuclear Information System (INIS)

    Soto, José Luis; Cabrera, Carmen M; Serrano, Salvio; López-Nevot, Miguel Ángel

    2005-01-01

    The role of genes involved in the control of progression from the G1 to the S phase of the cell cycle in melanoma tumors in not fully known. The aim of our study was to analyse mutations in TP53, CDKN1A, CDKN2A, and CDKN2B genes in melanoma tumors and melanoma cell lines We analysed 39 primary and metastatic melanomas and 9 melanoma cell lines by single-stranded conformational polymorphism (SSCP). The single-stranded technique showed heterozygous defects in the TP53 gene in 8 of 39 (20.5%) melanoma tumors: three new single point mutations in intronic sequences (introns 1 and 2) and exon 10, and three new single nucleotide polymorphisms located in introns 1 and 2 (C to T transition at position 11701 in intron 1; C insertion at position 11818 in intron 2; and C insertion at position 11875 in intron 2). One melanoma tumor exhibited two heterozygous alterations in the CDKN2A exon 1 one of which was novel (stop codon, and missense mutation). No defects were found in the remaining genes. These results suggest that these genes are involved in melanoma tumorigenesis, although they may be not the major targets. Other suppressor genes that may be informative of the mechanism of tumorigenesis in skin melanomas should be studied

  8. MiR-210 disturbs mitotic progression through regulating a group of mitosis-related genes

    OpenAIRE

    He, Jie; Wu, Jiangbin; Xu, Naihan; Xie, Weidong; Li, Mengnan; Li, Jianna; Jiang, Yuyang; Yang, Burton B.; Zhang, Yaou

    2012-01-01

    MiR-210 is up-regulated in multiple cancer types but its function is disputable and further investigation is necessary. Using a bioinformatics approach, we identified the putative target genes of miR-210 in hypoxia-induced CNE cells from genome-wide scale. Two functional gene groups related to cell cycle and RNA processing were recognized as the major targets of miR-210. Here, we investigated the molecular mechanism and biological consequence of miR-210 in cell cycle regulation, particularly ...

  9. An apoptotic cell cycle mutant in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Villadsen, Ingrid

    1996-01-01

    The simple eukaryote Saccharomyces cerevisiae has proved to be a useful organism for elucidating the mechanisms that govern cell cycle progression in eukaryotic cells. The excellent in vivo system permits a cell cycle study using temperature sensitive mutants. In addition, it is possible to study...... many genes and gene products from higher eukaryotes in Saccharomyces cerevisiae because many genes and biological processes are homologous or similar in lower and in higher eukaryotes. The highly developed methods of genetics and molecular biology greatly facilitates studies of higher eukaryotic...... processes.Programmmed cell death with apoptosis plays a major role in development and homeostatis in most, if not all, animal cells. Apoptosis is a morphologically distinct form of death, that requires the activation of a highly regulated suicide program. Saccharomyces cerevisiae provides a new system...

  10. ATM Expression Predicts Veliparib and Irinotecan Sensitivity in Gastric Cancer by Mediating P53-Independent Regulation of Cell Cycle and Apoptosis.

    Science.gov (United States)

    Subhash, Vinod Vijay; Tan, Shi Hui; Yeo, Mei Shi; Yan, Fui Leng; Peethala, Praveen C; Liem, Natalia; Krishnan, Vaidehi; Yong, Wei Peng

    2016-12-01

    Identification of synthetically lethal cellular targets and synergistic drug combinations is important in cancer chemotherapy as they help to overcome treatment resistance and increase efficacy. The Ataxia Telangiectasia Mutated (ATM) kinase is a nuclear protein that plays a major role in the initiation of DNA repair signaling and cell-cycle check points during DNA damage. Although ATM was shown to be associated with poor prognosis in gastric cancer, its implications as a predictive biomarker for cancer chemotherapy remain unexplored. The present study evaluated ATM-induced synthetic lethality and its role in sensitization of gastric cancer cells to PARP and TOP1 inhibitors, veliparib (ABT-888) and irinotecan (CPT-11), respectively. ATM expression was detected in a panel of gastric cell lines, and the IC 50 against each inhibitors was determined. The combinatorial effect of ABT-888 and CPT-11 in gastric cancer cells was also determined both in vitro and in vivo ATM deficiency was found to be associated with enhanced sensitivity to ABT-888 and CPT-11 monotherapy, hence suggesting a mechanism of synthetic lethality. Cells with high ATM expression showed reduced sensitivity to monotherapy; however, they showed a higher therapeutic effect with ABT-888 and CPT-11 combinatorial therapy. Furthermore, ATM expression was shown to play a major role in cellular homeostasis by regulating cell-cycle progression and apoptosis in a P53-independent manner. The present study highlights the clinical utility of ATM expression as a predictive marker for sensitivity of gastric cancer cells to PARP and TOP1 inhibition and provides a deeper mechanistic insight into ATM-dependent regulation of cellular processes. Mol Cancer Ther; 15(12); 3087-96. ©2016 AACR. ©2016 American Association for Cancer Research.

  11. Overexpression of cell cycle regulator CDCA3 promotes oral cancer progression by enhancing cell proliferation with prevention of G1 phase arrest

    International Nuclear Information System (INIS)

    Uchida, Fumihiko; Uzawa, Katsuhiro; Kasamatsu, Atsushi; Takatori, Hiroaki; Sakamoto, Yosuke; Ogawara, Katsunori; Shiiba, Masashi; Tanzawa, Hideki; Bukawa, Hiroki

    2012-01-01

    Cell division cycle associated 3 (CDCA3), part of the Skp1-cullin-F-box (SCF) ubiquitin ligase, refers to a trigger of mitotic entry and mediates destruction of the mitosis inhibitory kinase. Little is known about the relevance of CDCA3 to human malignancy including oral squamous cell carcinoma (OSCC). We aimed to characterize the expression state and function of CDCA3 in OSCC. We evaluated CDCA3 mRNA and protein expression in both OSCC-derived cell lines and primary OSCCs and performed functional analyses of CDCA3 in OSCC-derived cells using the shRNA system. The CDCA3 expression at both the mRNA and protein levels was frequently up-regulated in all cell lines examined and primary tumors (mRNA, 51/69, 74 %; protein, 79/95, 83 %) compared to normal controls (p < 0.001). In contrast, no significant level of CDCA3 protein expression was seen in oral premalignant lesions (OPLs) (n = 20) compared with the expression in OSCCs. Among the clinical variables analyzed, the CDCA3 expression status was closely related to tumor size (p < 0.05). In addition, suppression of CDCA3 expression with shRNA significantly (p < 0.05) inhibited cellular proliferation compared with the control cells by arresting cell-cycle progression at the G1 phase. Further, there was up-regulation of the cyclin-dependent kinase inhibitors (p21 Cip1 , p27 Kip1 , p15 INK4B , and p16 INK4A ) in the knockdown cells. The current results showed that overexpression of CDCA3 occurs frequently during oral carcinogenesis and this overexpression might be associated closely with progression of OSCCs by preventing the arrest of cell-cycle progression at the G1 phase via decreased expression of the cyclin-dependent kinase inhibitors

  12. Cell Cycle Deregulation in Ewing's Sarcoma Pathogenesis

    Science.gov (United States)

    Kowalewski, Ashley A.; Randall, R. Lor; Lessnick, Stephen L.

    2011-01-01

    Ewing's sarcoma is a highly aggressive pediatric tumor of bone that usually contains the characteristic chromosomal translocation t(11;22)(q24;q12). This translocation encodes the oncogenic fusion protein EWS/FLI, which acts as an aberrant transcription factor to deregulate target genes necessary for oncogenesis. One key feature of oncogenic transformation is dysregulation of cell cycle control. It is therefore likely that EWS/FLI and other cooperating mutations in Ewing's sarcoma modulate the cell cycle to facilitate tumorigenesis. This paper will summarize current published data associated with deregulation of the cell cycle in Ewing's sarcoma and highlight important questions that remain to be answered. PMID:21052502

  13. Cell Cycle Deregulation in Ewing's Sarcoma Pathogenesis

    Directory of Open Access Journals (Sweden)

    Ashley A. Kowalewski

    2011-01-01

    Full Text Available Ewing's sarcoma is a highly aggressive pediatric tumor of bone that usually contains the characteristic chromosomal translocation t(11;22(q24;q12. This translocation encodes the oncogenic fusion protein EWS/FLI, which acts as an aberrant transcription factor to deregulate target genes necessary for oncogenesis. One key feature of oncogenic transformation is dysregulation of cell cycle control. It is therefore likely that EWS/FLI and other cooperating mutations in Ewing's sarcoma modulate the cell cycle to facilitate tumorigenesis. This paper will summarize current published data associated with deregulation of the cell cycle in Ewing's sarcoma and highlight important questions that remain to be answered.

  14. Role of Protein Phosphorylation in the Regulation of Cell Cycle and DNA-Related Processes in Bacteria

    DEFF Research Database (Denmark)

    Garcia-Garcia, Transito; Poncet, Sandrine; Derouiche, Abderahmane

    2016-01-01

    In all living organisms, the phosphorylation of proteins modulates various aspects of their functionalities. In eukaryotes, protein phosphorylation plays a key role in cell signaling, gene expression, and differentiation. Protein phosphorylation is also involved in the global control of DNA repli...

  15. The role of plant growth substances in the regulation of the cell cycle in antheridial filaments of Chara vulgaris L. I. Effect of gibberellic acid on some, processes in the course of the cell cycle

    Directory of Open Access Journals (Sweden)

    Mirosław Godlewski

    2015-01-01

    Full Text Available The effect of gibberellic acid (10-4 M on the incorporation of 8-14C adenine, 3H phenylalanine, the dimensions of mitotic cells and the durations of particular stages in the cell cycle were studied in synchronously dividing cells of the antheridial filaments in Chara vulgaris L. during succesive periods of growth and differentiation. GA3 strongly stimulates the uptake of both labeled precursors in the course of a whole interphase and in all generations of the antheridial filaments; approximatively in proportion to the intensity of the process in the control. The gibberellin causes a slight increment in cell dimensions and strongly reduces the cell cycle durations: the S, G2, and M to a similar degree. The earlier is the generation of the antheridial filament, the more pronounced is the influence of the plant growth substance. Since the gibberellin stimulated the course of all examined processes, the present study did not reveal any stage of interphase to be especially sensitive to GA3. The results suggest to interpret the effect of GA3 as an unspecific stimulator of metabolism in cells of the antheridial filaments of Chara vulgaris L.

  16. The Src homology 2 protein Shb promotes cell cycle progression in murine hematopoietic stem cells by regulation of focal adhesion kinase activity

    Energy Technology Data Exchange (ETDEWEB)

    Gustafsson, Karin [Department of Medical Cell Biology, Uppsala University, Uppsala 751 23 (Sweden); Heffner, Garrett; Wenzel, Pamela L.; Curran, Matthew [HHMI, Children' s Hospital Boston, Harvard Medical School, Boston, 02115 MA (United States); Grawé, Jan [Department of Genetics and Pathology, Uppsala University, Uppsala 75185 (Sweden); McKinney-Freeman, Shannon L. [Department of Hematology, St. Jude Children' s Research Hospital, Memphis, TN 38105 (United States); Daley, George Q. [HHMI, Children' s Hospital Boston, Harvard Medical School, Boston, 02115 MA (United States); Welsh, Michael, E-mail: michael.welsh@mcb.uu.se [Department of Medical Cell Biology, Uppsala University, Uppsala 751 23 (Sweden)

    2013-07-15

    The widely expressed adaptor protein Shb has previously been reported to contribute to T cell function due to its association with the T cell receptor and furthermore, several of Shb's known interaction partners are established regulators of blood cell development and function. In addition, Shb deficient embryonic stem cells displayed reduced blood cell colony formation upon differentiation in vitro. The aim of the current study was therefore to explore hematopoietic stem and progenitor cell function in the Shb knockout mouse. Shb deficient bone marrow contained reduced relative numbers of long-term hematopoietic stem cells (LT-HSCs) that exhibited lower proliferation rates. Despite this, Shb knockout LT-HSCs responded promptly by entering the cell cycle in response to genotoxic stress by 5-fluorouracil treatment. In competitive LT-HSC transplantations, Shb null cells initially engrafted as well as the wild-type cells but provided less myeloid expansion over time. Moreover, Shb knockout bone marrow cells exhibited elevated basal activities of focal adhesion kinase/Rac1/p21-activated kinase signaling and reduced responsiveness to Stem Cell Factor stimulation. Consequently, treatment with a focal adhesion kinase inhibitor increased Shb knockout LT-HSC proliferation. The altered signaling characteristics thus provide a plausible mechanistic explanation for the changes in LT-HSC proliferation since these signaling intermediates have all been shown to participate in LT-HSC cell cycle control. In summary, the loss of Shb dependent signaling in bone marrow cells, resulting in elevated focal adhesion kinase activity and reduced proliferative responses in LT-HSCs under steady state hematopoiesis, confers a disadvantage to the maintenance of LT-HSCs over time. -- Highlights: • Shb is an adaptor protein operating downstream of tyrosine kinase receptors. • Shb deficiency reduces hematopoietic stem cell proliferation. • The proliferative effect of Shb occurs via

  17. Korean Byungkyul - Citrus platymamma Hort.et Tanaka flavonoids induces cell cycle arrest and apoptosis, regulating MMP protein expression in Hep3B hepatocellular carcinoma cells.

    Science.gov (United States)

    Hong, Gyeong Eun; Lee, Ho Jeong; Kim, Jin A; Yumnam, Silvia; Raha, Suchismita; Venkatarame Gowda Saralamma, Venu; Heo, Jeong Doo; Lee, Sang Joon; Kim, Eun Hee; Won, Chun Kil; Kim, Gon Sup

    2017-02-01

    Citrus platymamma Hort.et Tanaka is an indigenous fruit of Jeju island in Korea. In this study the bioactivity of C. platymamma flavonoids were evaluated on human hepatoma Hep3B cell lines. Eleven flavonoids were identified from the peels of C. platymamma Hort.et Tanaka through high-performance liquid chromatography-Tandem mass spectrometry and the anticancer effect of these C. platymamma flavonoids on human hepatoma Hep3B were studied. Chromatin condensation was observed in Hep3B cells treated with C. platymamma flavonoids. DNA fragmentation was confirmed through agarose gel electrophoresis and TUNEL assay. An increase in the total apoptotic cells and G2/M cell cycle arrest with decreased protein expression of CDC25C, CDK1, cyclin B1 and p21 were observed in Hep3B cells treated with flavonoids of C. platymamma. Further, protein expression of Bcl-XL, Bax, caspase-3 and -9 were also modulated by C. platymamma flavonoids treatment indicating that cell death is through intrinsic apoptotic pathway. Moreover, C. platymamma flavonoids also regulated the phosphorylation of MAPKs, PI3K, and Akt in Hep3B cells. Relevant to inhibiting metastasis, C. platymamma treatment reduced wound closure of Hep3B cells and the protein expression of matrix metalloproteinase-2 and -9 were reduced in C. platymamma treated cells. The results show that C. platymamma flavonoids induce cell cycle arrest and apoptosis following activation of MAPKs and suppression of PI3K/Akt pathway which eventually inhibits cell migration in Hep3B cells. The finding provides evidence on biochemical activities of C. platymamma Hort.et Tanaka, which would be an essential agent for hepatocellular carcinoma (HCC) treatment.

  18. The Src homology 2 protein Shb promotes cell cycle progression in murine hematopoietic stem cells by regulation of focal adhesion kinase activity

    International Nuclear Information System (INIS)

    Gustafsson, Karin; Heffner, Garrett; Wenzel, Pamela L.; Curran, Matthew; Grawé, Jan; McKinney-Freeman, Shannon L.; Daley, George Q.; Welsh, Michael

    2013-01-01

    The widely expressed adaptor protein Shb has previously been reported to contribute to T cell function due to its association with the T cell receptor and furthermore, several of Shb's known interaction partners are established regulators of blood cell development and function. In addition, Shb deficient embryonic stem cells displayed reduced blood cell colony formation upon differentiation in vitro. The aim of the current study was therefore to explore hematopoietic stem and progenitor cell function in the Shb knockout mouse. Shb deficient bone marrow contained reduced relative numbers of long-term hematopoietic stem cells (LT-HSCs) that exhibited lower proliferation rates. Despite this, Shb knockout LT-HSCs responded promptly by entering the cell cycle in response to genotoxic stress by 5-fluorouracil treatment. In competitive LT-HSC transplantations, Shb null cells initially engrafted as well as the wild-type cells but provided less myeloid expansion over time. Moreover, Shb knockout bone marrow cells exhibited elevated basal activities of focal adhesion kinase/Rac1/p21-activated kinase signaling and reduced responsiveness to Stem Cell Factor stimulation. Consequently, treatment with a focal adhesion kinase inhibitor increased Shb knockout LT-HSC proliferation. The altered signaling characteristics thus provide a plausible mechanistic explanation for the changes in LT-HSC proliferation since these signaling intermediates have all been shown to participate in LT-HSC cell cycle control. In summary, the loss of Shb dependent signaling in bone marrow cells, resulting in elevated focal adhesion kinase activity and reduced proliferative responses in LT-HSCs under steady state hematopoiesis, confers a disadvantage to the maintenance of LT-HSCs over time. -- Highlights: • Shb is an adaptor protein operating downstream of tyrosine kinase receptors. • Shb deficiency reduces hematopoietic stem cell proliferation. • The proliferative effect of Shb occurs via increased

  19. Cell cycle pathway dysregulation in human keratinocytes during chronic exposure to low arsenite.

    Science.gov (United States)

    Al-Eryani, Laila; Waigel, Sabine; Jala, Venkatakrishna; Jenkins, Samantha F; States, J Christopher

    2017-09-15

    Arsenic is naturally prevalent in the earth's crust and widely distributed in air and water. Chronic low arsenic exposure is associated with several cancers in vivo, including skin cancer, and with transformation in vitro of cell lines including immortalized human keratinocytes (HaCaT). Arsenic also is associated with cell cycle dysregulation at different exposure levels in multiple cell lines. In this work, we analyzed gene expression in HaCaT cells to gain an understanding of gene expression changes contributing to transformation at an early time point. HaCaT cells were exposed to 0 or 100nM NaAsO 2 for 7weeks. Total RNA was purified and analyzed by microarray hybridization. Differential expression with fold change≥|1.5| and p-value≤0.05 was determined using Partek Genomic Suite™ and pathway and network analyses using MetaCore™ software (FDR≤0.05). Cell cycle analysis was performed using flow cytometry. 644 mRNAs were differentially expressed. Cell cycle/cell cycle regulation pathways predominated in the list of dysregulated pathways. Genes involved in replication origin licensing were enriched in the network. Cell cycle assay analysis showed an increase in G2/M compartment in arsenite-exposed cells. Arsenite exposure induced differential gene expression indicating dysregulation of cell cycle control, which was confirmed by cell cycle analysis. The results suggest that cell cycle dysregulation is an early event in transformation manifested in cells unable to transit G2/M efficiently. Further study at later time points will reveal additional changes in gene expression related to transformation processes. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Lobaplatin arrests cell cycle progression in human hepatocellular carcinoma cells

    Directory of Open Access Journals (Sweden)

    Chen Chang-Jie

    2010-10-01

    Full Text Available Abstract Background Hepatocellular carcinoma (HCC still is a big burden for China. In recent years, the third-generation platinum compounds have been proposed as potential active agents for HCC. However, more experimental and clinical data are warranted to support the proposal. In the present study, the effect of lobaplatin was assessed in five HCC cell lines and the underlying molecular mechanisms in terms of cell cycle kinetics were explored. Methods Cytotoxicity of lobaplatin to human HCC cell lines was examined using MTT cell proliferation assay. Cell cycle distribution was determined by flow cytometry. Expression of cell cycle-regulated genes was examined at both the mRNA (RT-PCR and protein (Western blot levels. The phosphorylation status of cyclin-dependent kinases (CDKs and retinoblastoma (Rb protein was also examined using Western blot analysis. Results Lobaplatin inhibited proliferation of human HCC cells in a dose-dependent manner. For the most sensitive SMMC-7721 cells, lobaplatin arrested cell cycle progression in G1 and G2/M phases time-dependently which might be associated with the down-regulation of cyclin B, CDK1, CDC25C, phosphorylated CDK1 (pCDK1, pCDK4, Rb, E2F, and pRb, and the up-regulation of p53, p21, and p27. Conclusion Cytotoxicity of lobaplatin in human HCC cells might be due to its ability to arrest cell cycle progression which would contribute to the potential use of lobaplatin for the management of HCC.

  1. CDKL5, a novel MYCN-repressed gene, blocks cell cycle and promotes differentiation of neuronal cells

    OpenAIRE

    Valli, Emanuele; Trazzi, Stefania; Fuchs, Claudia; Erriquez, Daniela; Bartesaghi, Renata; Perini, Giovanni; Ciani, Elisabetta

    2012-01-01

    Mutations in the CDKL5 (cyclin-dependent kinase-like 5) gene are associated with a severe epileptic encephalopathy (early infantile epileptic encephalopathy type 2, EIEE2) characterized by early-onset intractable seizures, infantile spasms, severe developmental delay, intellectual disability, and Rett syndrome (RTT)-like features. Despite the clear involvement of CDKL5 mutations in intellectual disability, the function of this protein during brain development and the molecular mechanisms invo...

  2. Studying gene regulation in methanogenic archaea.

    Science.gov (United States)

    Rother, Michael; Sattler, Christian; Stock, Tilmann

    2011-01-01

    Methanogenic archaea are a unique group of strictly anaerobic microorganisms characterized by their ability, and dependence, to convert simple C1 and C2 compounds to methane for growth. The major models for studying the biology of methanogens are members of the Methanococcus and Methanosarcina species. Recent development of sophisticated tools for molecular analysis and for genetic manipulation allows investigating not only their metabolism but also their cell cycle, and their interaction with the environment in great detail. One aspect of such analyses is assessment and dissection of methanoarchaeal gene regulation, for which, at present, only a handful of cases have been investigated thoroughly, partly due to the great methodological effort required. However, it becomes more and more evident that many new regulatory paradigms can be unraveled in this unique archaeal group. Here, we report both molecular and physiological/genetic methods to assess gene regulation in Methanococcus maripaludis and Methanosarcina acetivorans, which should, however, be applicable for other methanogens as well. Copyright © 2011 Elsevier Inc. All rights reserved.

  3. An overexpression screen in Drosophila for genes that restrict growth or cell-cycle progression in the developing eye.

    OpenAIRE

    Tseng, Ai-Sun Kelly; Hariharan, Iswar K

    2002-01-01

    We screened for genes that, when overexpressed in the proliferating cells of the eye imaginal disc, result in a reduction in the size of the adult eye. After crossing the collection of 2296 EP lines to the ey-GAL4 driver, we identified 46 lines, corresponding to insertions in 32 different loci, that elicited a small eye phenotype. These lines were classified further by testing for an effect in postmitotic cells using the sev-GAL4 driver, by testing for an effect in the wing using en-GAL4, and...

  4. Manipulation of cell cycle progression can counteract the apparent loss of correction frequency following oligonucleotide-directed gene repair

    Directory of Open Access Journals (Sweden)

    Kmiec Eric B

    2007-02-01

    Full Text Available Abstract Background Single-stranded oligonucleotides (ssODN are used routinely to direct specific base alterations within mammalian genomes that result in the restoration of a functional gene. Despite success with the technique, recent studies have revealed that following repair events, correction frequencies decrease as a function of time, possibly due to a sustained activation of damage response signals in corrected cells that lead to a selective stalling. In this study, we use thymidine to slow down the replication rate to enhance repair frequency and to maintain substantial levels of correction over time. Results First, we utilized thymidine to arrest cells in G1 and released the cells into S phase, at which point specific ssODNs direct the highest level of correction. Next, we devised a protocol in which cells are maintained in thymidine following the repair reaction, in which the replication is slowed in both corrected and non-corrected cells and the initial correction frequency is retained. We also present evidence that cells enter a senescence state upon prolonged treatment with thymidine but this passage can be avoided by removing thymidine at 48 hours. Conclusion Taken together, we believe that thymidine may be used in a therapeutic fashion to enable the maintenance of high levels of treated cells bearing repaired genes.

  5. Dendrobium candidum inhibits MCF-7 cells proliferation by inducing cell cycle arrest at G2/M phase and regulating key biomarkers

    Directory of Open Access Journals (Sweden)

    Sun J

    2015-12-01

    <0.05. The general apoptosis biomarker, Bcl-2, was significantly decreased and the Bax was significantly increased compared to the control group (P<0.05. In contrast to that in MCF-7, D. candidum does not affect cell proliferation at any concentration and any time points in normal breast epithelial cells, MCF10A cells. Conclusion: D. candidum could decrease the cell viability of MCF-7 cells by inducing cell cycle arrest at the G2/M phase and regulating the key biomarkers in breast cancer cells. Keywords: breast cancer, D. candidum, proliferation, biomarker, inhibition

  6. Model-based investigation of the circadian clock and cell cycle coupling in mouse embryonic fibroblasts: Prediction of RevErb-α up-regulation during mitosis

    OpenAIRE

    Traynard , Pauline; Feillet , Céline; Soliman , Sylvain; Delaunay , Franck; Fages , François

    2016-01-01

    International audience; Experimental observations have put in evidence autonomous self-sustained circadian oscillators in most mammalian cells, and proved the existence of molecular links between the circadian clock and the cell cycle. Some mathematical models have also been built to assess conditions of control of the cell cycle by the circadian clock. However, recent studies in individual NIH3T3 fibroblasts have shown an unexpected acceleration of the circadian clock together with the cell ...

  7. Cell cycle controls: potential targets for chemical carcinogens?

    OpenAIRE

    Afshari, C A; Barrett, J C

    1993-01-01

    The progression of the cell cycle is controlled by the action of both positive and negative growth regulators. The key players in this activity include a family of cyclins and cyclin-dependent kinases, which are themselves regulated by other kinases and phosphatases. Maintenance of balanced cell cycle controls may be directly linked to genomic stability. Loss of the check-points involved in cell cycle control may result in unrepaired DNA damage during DNA synthesis or mitosis leading to genet...

  8. High-resolution transcription atlas of the mitotic cell cycle in budding yeast

    DEFF Research Database (Denmark)

    Granovskaia, Marina V; Jensen, Lars J; Ritchie, Matthew E

    2010-01-01

    Extensive transcription of non-coding RNAs has been detected in eukaryotic genomes and is thought to constitute an additional layer in the regulation of gene expression. Despite this role, their transcription through the cell cycle has not been studied; genome-wide approaches have only focused on...

  9. Cellular plasticity enables adaptation to unforeseen cell-cycle rewiring challenges.

    Directory of Open Access Journals (Sweden)

    Yair Katzir

    Full Text Available The fundamental dynamics of the cell cycle, underlying cell growth and reproduction, were previously found to be robust under a wide range of environmental and internal perturbations. This property was commonly attributed to its network structure, which enables the coordinated interactions among hundreds of proteins. Despite significant advances in deciphering the components and autonomous interactions of this network, understanding the interfaces of the cell cycle with other major cellular processes is still lacking. To gain insight into these interfaces, we used the process of genome-rewiring in yeast by placing an essential metabolic gene HIS3 from the histidine biosynthesis pathway, under the exclusive regulation of different cell-cycle promoters. In a medium lacking histidine and under partial inhibition of the HIS3p, the rewired cells encountered an unforeseen multitasking challenge; the cell-cycle regulatory genes were required to regulate the essential histidine-pathway gene in concert with the other metabolic demands, while simultaneously driving the cell cycle through its proper temporal phases. We show here that chemostat cell populations with rewired cell-cycle promoters adapted within a short time to accommodate the inhibition of HIS3p and stabilized a new phenotypic state. Furthermore, a significant fraction of the population was able to adapt and grow into mature colonies on plates under such inhibiting conditions. The adapted state was shown to be stably inherited across generations. These adaptation dynamics were accompanied by a non-specific and irreproducible genome-wide transcriptional response. Adaptation of the cell-cycle attests to its multitasking capabilities and flexible interface with cellular metabolic processes and requirements. Similar adaptation features were found in our previous work when rewiring HIS3 to the GAL system and switching cells from galactose to glucose. Thus, at the basis of cellular plasticity is

  10. Cellular plasticity enables adaptation to unforeseen cell-cycle rewiring challenges.

    Science.gov (United States)

    Katzir, Yair; Stolovicki, Elad; Stern, Shay; Braun, Erez

    2012-01-01

    The fundamental dynamics of the cell cycle, underlying cell growth and reproduction, were previously found to be robust under a wide range of environmental and internal perturbations. This property was commonly attributed to its network structure, which enables the coordinated interactions among hundreds of proteins. Despite significant advances in deciphering the components and autonomous interactions of this network, understanding the interfaces of the cell cycle with other major cellular processes is still lacking. To gain insight into these interfaces, we used the process of genome-rewiring in yeast by placing an essential metabolic gene HIS3 from the histidine biosynthesis pathway, under the exclusive regulation of different cell-cycle promoters. In a medium lacking histidine and under partial inhibition of the HIS3p, the rewired cells encountered an unforeseen multitasking challenge; the cell-cycle regulatory genes were required to regulate the essential histidine-pathway gene in concert with the other metabolic demands, while simultaneously driving the cell cycle through its proper temporal phases. We show here that chemostat cell populations with rewired cell-cycle promoters adapted within a short time to accommodate the inhibition of HIS3p and stabilized a new phenotypic state. Furthermore, a significant fraction of the population was able to adapt and grow into mature colonies on plates under such inhibiting conditions. The adapted state was shown to be stably inherited across generations. These adaptation dynamics were accompanied by a non-specific and irreproducible genome-wide transcriptional response. Adaptation of the cell-cycle attests to its multitasking capabilities and flexible interface with cellular metabolic processes and requirements. Similar adaptation features were found in our previous work when rewiring HIS3 to the GAL system and switching cells from galactose to glucose. Thus, at the basis of cellular plasticity is the emergence of a yet

  11. Protein tyrosine nitration in the cell cycle

    International Nuclear Information System (INIS)

    Jia, Min; Mateoiu, Claudia; Souchelnytskyi, Serhiy

    2011-01-01

    Highlights: → Enrichment of 3-nitrotyrosine containing proteins from cells synchronized in different phases of the cell cycle. → Identification of 76 tyrosine nitrated proteins that change expression during the cell cycle. → Nineteen identified proteins were previously described as regulators of cell proliferation. -- Abstract: Nitration of tyrosine residues in proteins is associated with cell response to oxidative/nitrosative stress. Tyrosine nitration is relatively low abundant post-translational modification that may affect protein functions. Little is known about the extent of protein tyrosine nitration in cells during progression through the cell cycle. Here we report identification of proteins enriched for tyrosine nitration in cells synchronized in G0/G1, S or G2/M phases of the cell cycle. We identified 27 proteins in cells synchronized in G0/G1 phase, 37 proteins in S phase synchronized cells, and 12 proteins related to G2/M phase. Nineteen of the identified proteins were previously described as regulators of cell proliferation. Thus, our data indicate which tyrosine nitrated proteins may affect regulation of the cell cycle.

  12. miR-139-5p regulates proliferation, apoptosis, and cell cycle of uterine leiomyoma cells by targeting TPD52

    Directory of Open Access Journals (Sweden)

    Chen H

    2016-10-01

    Full Text Available Hong Chen,1 Hong Xu,1 Yu-gang Meng,1 Yun Zhang,2 Jun-ying Chen,1 Xiao-ning Wei1 1Department of Gynaecology, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, 2Department of Gynaecology, The People’s Hospital of Suzhou High Tech District, Suzhou, Jiangsu, People’s Republic of China Background: Uterine leiomyoma is one of the most common benign tumors in women. It dramatically decreases the quality of life in the affected women. However, there is a lack of effective treatment paradigms. Micro-RNAs are small noncoding RNA molecules that are extensively expressed in organisms, and they are interrelated with the occurrence and development of the tumor. miR-139-5p was found to be downregulated in various cancers, but its function and mechanism in uterine leiomyoma remain unknown. The aim of this study was to investigate the role of miR-139-5p and its target gene in uterine leiomyoma.Methods: By using a bioinformatic assay, it was found that TPD52 was a potential target gene of miR-139-5p. Then, expressions of miR-139-5p and TPD52 in uterine leiomyoma and adjacent myometrium tissues were evaluated by quantitative real-time polymerase chain reaction and Western blot. Proliferation, apoptosis, and cell cycle of uterine leiomyoma cells transfected by miR-139-5p mimics or TPD52 siRNA were determined.Results: It was observed that the expression of miR-139-5p in uterine leiomyoma tissues was significantly lower (P<0.001 than that in the adjacent myometrium tissues. Overexpression of miR-139-5p inhibited the growth of uterine leiomyoma cells and induced apoptosis and G1 phase arrest. Dual-luciferase reporter assay and Western blot validated that TPD52 is the target gene of miR-139-5p. Furthermore, downregulation of TPD52 by siRNA in uterine leiomyoma cells inhibited cell proliferation and induced cell apoptosis and G1 phase arrest.Conclusion: Data suggested that miR-139-5p inhibited the proliferation of uterine leiomyoma cells

  13. Regulation of eucaryotic gene expression

    Energy Technology Data Exchange (ETDEWEB)

    Brent, R.; Ptashne, M.S

    1989-05-23

    This patent describes a method of regulating the expression of a gene in a eucaryotic cell. The method consists of: providing in the eucaryotic cell, a peptide, derived from or substantially similar to a peptide of a procaryotic cell able to bind to DNA upstream from or within the gene, the amount of the peptide being sufficient to bind to the gene and thereby control expression of the gene.

  14. CSL protein regulates transcription of genes required to prevent catastrophic mitosis in fission yeast.

    Science.gov (United States)

    Převorovský, Martin; Oravcová, Martina; Zach, Róbert; Jordáková, Anna; Bähler, Jürg; Půta, František; Folk, Petr

    2016-11-16

    For every eukaryotic cell to grow and divide, intricately coordinated action of numerous proteins is required to ensure proper cell-cycle progression. The fission yeast Schizosaccharomyces pombe has been instrumental in elucidating the fundamental principles of cell-cycle control. Mutations in S. pombe 'cut' (cell untimely torn) genes cause failed coordination between cell and nuclear division, resulting in catastrophic mitosis. Deletion of cbf11, a fission yeast CSL transcription factor gene, triggers a 'cut' phenotype, but the precise role of Cbf11 in promoting mitotic fidelity is not known. We report that Cbf11 directly activates the transcription of the acetyl-coenzyme A carboxylase gene cut6, and the biotin uptake/biosynthesis genes vht1 and bio2, with the former 2 implicated in mitotic fidelity. Cbf11 binds to a canonical, metazoan-like CSL response element (GTGGGAA) in the cut6 promoter. Expression of Cbf11 target genes shows apparent oscillations during the cell cycle using temperature-sensitive cdc25-22 and cdc10-M17 block-release experiments, but not with other synchronization methods. The penetrance of catastrophic mitosis in cbf11 and cut6 mutants is nutrient-dependent. We also show that drastic decrease in biotin availability arrests cell proliferation but does not cause mitotic defects. Taken together, our results raise the possibility that CSL proteins play conserved roles in regulating cell-cycle progression, and they could guide experiments into mitotic CSL functions in mammals.

  15. Hedgehog signaling acts with the temporal cascade to promote neuroblast cell cycle exit.

    Directory of Open Access Journals (Sweden)

    Phing Chian Chai

    Full Text Available In Drosophila postembryonic neuroblasts, transition in gene expression programs of a cascade of transcription factors (also known as the temporal series acts together with the asymmetric division machinery to generate diverse neurons with distinct identities and regulate the end of neuroblast proliferation. However, the underlying mechanism of how this "temporal series" acts during development remains unclear. Here, we show that Hh signaling in the postembryonic brain is temporally regulated; excess (earlier onset of Hh signaling causes premature neuroblast cell cycle exit and under-proliferation, whereas loss of Hh signaling causes delayed cell cycle exit and excess proliferation. Moreover, the Hh pathway functions downstream of Castor but upstream of Grainyhead, two components of the temporal series, to schedule neuroblast cell cycle exit. Interestingly, hh is likely a target of Castor. Hence, Hh signaling provides a link between the temporal series and the asymmetric division machinery in scheduling the end of neurogenesis.

  16. Identification of Human HK Genes and Gene Expression Regulation Study in Cancer from Transcriptomics Data Analysis

    Science.gov (United States)

    Zhang, Zhang; Liu, Jingxing; Wu, Jiayan; Yu, Jun

    2013-01-01

    The regulation of gene expression is essential for eukaryotes, as it drives the processes of cellular differentiation and morphogenesis, leading to the creation of different cell types in multicellular organisms. RNA-Sequencing (RNA-Seq) provides researchers with a powerful toolbox for characterization and quantification of transcriptome. Many different human tissue/cell transcriptome datasets coming from RNA-Seq technology are available on public data resource. The fundamental issue here is how to develop an effective analysis method to estimate expression pattern similarities between different tumor tissues and their corresponding normal tissues. We define the gene expression pattern from three directions: 1) expression breadth, which reflects gene expression on/off status, and mainly concerns ubiquitously expressed genes; 2) low/high or constant/variable expression genes, based on gene expression level and variation; and 3) the regulation of gene expression at the gene structure level. The cluster analysis indicates that gene expression pattern is higher related to physiological condition rather than tissue spatial distance. Two sets of human housekeeping (HK) genes are defined according to cell/tissue types, respectively. To characterize the gene expression pattern in gene expression level and variation, we firstly apply improved K-means algorithm and a gene expression variance model. We find that cancer-associated HK genes (a HK gene is specific in cancer group, while not in normal group) are expressed higher and more variable in cancer condition than in normal condition. Cancer-associated HK genes prefer to AT-rich genes, and they are enriched in cell cycle regulation related functions and constitute some cancer signatures. The expression of large genes is also avoided in cancer group. These studies will help us understand which cell type-specific patterns of gene expression differ among different cell types, and particularly for cancer. PMID:23382867

  17. Lactobacillus Decelerates Cervical Epithelial Cell Cycle Progression

    Science.gov (United States)

    Vielfort, Katarina; Weyler, Linda; Söderholm, Niklas; Engelbrecht, Mattias; Löfmark, Sonja; Aro, Helena

    2013-01-01

    We investigated cell cycle progression in epithelial cervical ME-180 cells during colonization of three different Lactobacillus species utilizing live cell microscopy, bromodeoxyuridine incorporation assays, and flow cytometry. The colonization of these ME-180 cells by L. rhamnosus and L. reuteri, originating from human gastric epithelia and saliva, respectively, was shown to reduce cell cycle progression and to cause host cells to accumulate in the G1 phase of the cell cycle. The G1 phase accumulation in L. rhamnosus-colonized cells was accompanied by the up-regulation and nuclear accumulation of p21. By contrast, the vaginal isolate L. crispatus did not affect cell cycle progression. Furthermore, both the supernatants from the lactic acid-producing L. rhamnosus colonies and lactic acid added to cell culture media were able to reduce the proliferation of ME-180 cells. In this study, we reveal the diversity of the Lactobacillus species to affect host cell cycle progression and demonstrate that L. rhamnosus and L. reuteri exert anti-proliferative effects on human cervical carcinoma cells. PMID:23675492

  18. Lactobacillus decelerates cervical epithelial cell cycle progression.

    Directory of Open Access Journals (Sweden)

    Katarina Vielfort

    Full Text Available We investigated cell cycle progression in epithelial cervical ME-180 cells during colonization of three different Lactobacillus species utilizing live cell microscopy, bromodeoxyuridine incorporation assays, and flow cytometry. The colonization of these ME-180 cells by L. rhamnosus and L. reuteri, originating from human gastric epithelia and saliva, respectively, was shown to reduce cell cycle progression and to cause host cells to accumulate in the G1 phase of the cell cycle. The G1 phase accumulation in L. rhamnosus-colonized cells was accompanied by the up-regulation and nuclear accumulation of p21. By contrast, the vaginal isolate L. crispatus did not affect cell cycle progression. Furthermore, both the supernatants from the lactic acid-producing L. rhamnosus colonies and lactic acid added to cell culture media were able to reduce the proliferation of ME-180 cells. In this study, we reveal the diversity of the Lactobacillus species to affect host cell cycle progression and demonstrate that L. rhamnosus and L. reuteri exert anti-proliferative effects on human cervical carcinoma cells.

  19. A hybrid mammalian cell cycle model

    Directory of Open Access Journals (Sweden)

    Vincent Noël

    2013-08-01

    Full Text Available Hybrid modeling provides an effective solution to cope with multiple time scales dynamics in systems biology. Among the applications of this method, one of the most important is the cell cycle regulation. The machinery of the cell cycle, leading to cell division and proliferation, combines slow growth, spatio-temporal re-organisation of the cell, and rapid changes of regulatory proteins concentrations induced by post-translational modifications. The advancement through the cell cycle comprises a well defined sequence of stages, separated by checkpoint transitions. The combination of continuous and discrete changes justifies hybrid modelling approaches to cell cycle dynamics. We present a piecewise-smooth version of a mammalian cell cycle model, obtained by hybridization from a smooth biochemical model. The approximate hybridization scheme, leading to simplified reaction rates and binary event location functions, is based on learning from a training set of trajectories of the smooth model. We discuss several learning strategies for the parameters of the hybrid model.

  20. Cell Cycle Inhibition To Treat Sleeping Sickness

    Directory of Open Access Journals (Sweden)

    Conrad L. Epting

    2017-09-01

    Full Text Available African trypanosomiasis is caused by infection with the protozoan parasite Trypanosoma brucei. During infection, this pathogen divides rapidly to high density in the bloodstream of its mammalian host in a manner similar to that of leukemia. Like all eukaryotes, T. brucei has a cell cycle involving the de novo synthesis of DNA regulated by ribonucleotide reductase (RNR, which catalyzes the conversion of ribonucleotides into their deoxy form. As an essential enzyme for the cell cycle, RNR is a common target for cancer chemotherapy. We hypothesized that inhibition of RNR by genetic or pharmacological means would impair parasite growth in vitro and prolong the survival of infected animals. Our results demonstrate that RNR inhibition is highly effective in suppressing parasite growth both in vitro and in vivo. These results support drug discovery efforts targeting the cell cycle, not only for African trypanosomiasis but possibly also for other infections by eukaryotic pathogens.

  1. Cell cycle arrest as a hallmark of insect diapause: Changes in gene transcription during diapause induction in the drosophilid fly, Chymomyza costata

    Czech Academy of Sciences Publication Activity Database

    Košťál, Vladimír; Šimůnková, P.; Kobelková, Alena; Shimada, K.

    2009-01-01

    Roč. 39, č. 12 (2009), s. 875-883 ISSN 0965-1748 R&D Projects: GA MŠk LC07032 Institutional research plan: CEZ:AV0Z50070508 Keywords : Drosophila * cell cycle arrest * diapause Subject RIV: ED - Physiology Impact factor: 3.117, year: 2009

  2. Certain and progressive methylation of histone H4 at lysine 20 during the cell cycle.

    Science.gov (United States)

    Pesavento, James J; Yang, Hongbo; Kelleher, Neil L; Mizzen, Craig A

    2008-01-01

    Methylation of histone H4 at lysine 20 (K20) has been implicated in transcriptional activation, gene silencing, heterochromatin formation, mitosis, and DNA repair. However, little is known about how this modification is regulated or how it contributes to these diverse processes. Metabolic labeling and top-down mass spectrometry reveal that newly synthesized H4 is progressively methylated at K20 during the G(2), M, and G(1) phases of the cell cycle in a process that is largely inescapable and irreversible. Approximately 98% of new H4 becomes dimethylated within two to three cell cycles, and K20 methylation turnover in vivo is undetectable. New H4 is methylated regardless of prior acetylation, and acetylation occurs predominantly on K20-dimethylated H4, refuting the hypothesis that K20 methylation antagonizes H4 acetylation and represses transcription epigenetically. Despite suggestions that it is required for normal mitosis and cell cycle progression, K20 methylation proceeds normally during colchicine treatment. Moreover, delays in PR-Set7 synthesis and K20 methylation which accompany altered cell cycle progression during sodium butyrate treatment appear to be secondary to histone hyperacetylation or other effects of butyrate since depletion of PR-Set7 did not affect cell cycle progression. Together, our data provide an unbiased perspective of the regulation and function of K20 methylation.

  3. P27 in cell cycle control and cancer

    DEFF Research Database (Denmark)

    Møller, Michael Boe

    2000-01-01

    In order to survive, cells need tight control of cell cycle progression. The control mechanisms are often lost in human cancer cells. The cell cycle is driven forward by cyclin-dependent kinases (CDKs). The CDK inhibitors (CKIs) are important regulators of the CDKs. As the name implies, CKIs were...

  4. The simian immunodeficiency virus targets central cell cycle functions through transcriptional repression in vivo.

    Directory of Open Access Journals (Sweden)

    Carl-Magnus Hogerkorp

    Full Text Available A massive and selective loss of CD4+ memory T cells occurs during the acute phase of immunodeficiency virus infections. The mechanism of this depletion is poorly understood but constitutes a key event with implications for progression. We assessed gene expression of purified T cells in Rhesus Macaques during acute SIVmac239 infection in order to define mechanisms of pathogenesis. We observe a general transcriptional program of over 1,600 interferon-stimulated genes induced in all T cells by the infection. Furthermore, we identify 113 transcriptional changes that are specific to virally infected cells. A striking downregulation of several key cell cycle regulator genes was observed and shared promotor-region E2F binding sites in downregulated genes suggested a targeted transcriptional control of an E2F regulated cell cycle program. In addition, the upregulation of the gene for the fundamental regulator of RNA polymerase II, TAF7, demonstrates that viral interference with the cell cycle and transcriptional regulation programs may be critical components during the establishment of a pathogenic infection in vivo.

  5. The B-MYB transcriptional network guides cell cycle progression and fate decisions to sustain self-renewal and the identity of pluripotent stem cells.

    Science.gov (United States)

    Zhan, Ming; Riordon, Daniel R; Yan, Bin; Tarasova, Yelena S; Bruweleit, Sarah; Tarasov, Kirill V; Li, Ronald A; Wersto, Robert P; Boheler, Kenneth R

    2012-01-01

    Embryonic stem cells (ESCs) are pluripotent and have unlimited self-renewal capacity. Although pluripotency and differentiation have been examined extensively, the mechanisms responsible for self-renewal are poorly understood and are believed to involve an unusual cell cycle, epigenetic regulators and pluripotency-promoting transcription factors. Here we show that B-MYB, a cell cycle regulated phosphoprotein and transcription factor critical to the formation of inner cell mass, is central to the transcriptional and co-regulatory networks that sustain normal cell cycle progression and self-renewal properties of ESCs. Phenotypically, B-MYB is robustly expressed in ESCs and induced pluripotent stem cells (iPSCs), and it is present predominantly in a hypo-phosphorylated state. Knockdown of B-MYB results in functional cell cycle abnormalities that involve S, G2 and M phases, and reduced expression of critical cell cycle regulators like ccnb1 and plk1. By conducting gene expression profiling on control and B-MYB deficient cells, ChIP-chip experiments, and integrative computational analyses, we unraveled a highly complex B-MYB-mediated transcriptional network that guides ESC self-renewal. The network encompasses critical regulators of all cell cycle phases and epigenetic regulators, pluripotency transcription factors, and differentiation determinants. B-MYB along with E2F1 and c-MYC preferentially co-regulate cell cycle target genes. B-MYB also co-targets genes regulated by OCT4, SOX2 and NANOG that are significantly associated with stem cell differentiation, embryonic development, and epigenetic control. Moreover, loss of B-MYB leads to a breakdown of the transcriptional hierarchy present in ESCs. These results coupled with functional studies demonstrate that B-MYB not only controls and accelerates cell cycle progression in ESCs it contributes to fate decisions and maintenance of pluripotent stem cell identity.

  6. Direct Regulation of tRNA and 5S rRNA Gene Transcription by Polo-like Kinase 1

    NARCIS (Netherlands)

    Fairley, Jennifer A.; Mitchell, Louise E.; Berg, Tracy; Kenneth, Niall S.; von Schubert, Conrad; Sillje, Herman H. W.; Medema, Rene H.; Nigg, Erich A.; White, Robert J.

    2012-01-01

    Polo-like kinase Plk1 controls numerous aspects of cell-cycle progression. We show that it associates with tRNA and 5S rRNA genes and regulates their transcription by RNA polymerase Ill (pol Ill) through direct binding and phosphorylation of transcription factor Brit During interphase, Plk1 promotes

  7. Small-Molecule Inhibition of Rho/MKL/SRF Transcription in Prostate Cancer Cells: Modulation of Cell Cycle, ER Stress, and Metastasis Gene Networks

    Directory of Open Access Journals (Sweden)

    Chris R. Evelyn

    2016-05-01

    Full Text Available Metastasis is the major cause of cancer deaths and control of gene transcription has emerged as a critical contributing factor. RhoA- and RhoC-induced gene transcription via the actin-regulated transcriptional co-activator megakaryocytic leukemia (MKL and serum response factor (SRF drive metastasis in breast cancer and melanoma. We recently identified a compound, CCG-1423, which blocks Rho/MKL/SRF-mediated transcription and inhibits PC-3 prostate cancer cell invasion. Here, we undertook a genome-wide expression study in PC-3 cells to explore the mechanism and function of this compound. There was significant overlap in the genes modulated by CCG-1423 and Latrunculin B (Lat B, which blocks the Rho/MKL/SRF pathway by preventing actin polymerization. In contrast, the general transcription inhibitor 5,6-dichloro-1-β-d-ribofuranosyl-1H-benzimidazole (DRB showed a markedly different pattern. Effects of CCG-1423 and Lat B on gene expression correlated with literature studies of MKL knock-down. Gene sets involved in DNA synthesis and repair, G1/S transition, and apoptosis were modulated by CCG-1423. It also upregulated genes involved in endoplasmic reticulum stress. Targets of the known Rho target transcription factor family E2F and genes related to melanoma progression and metastasis were strongly suppressed by CCG-1423. These results confirm the ability of our compound to inhibit expression of numerous Rho/MKL-dependent genes and show effects on stress pathways as well. This suggests a novel approach to targeting aggressive cancers and metastasis.

  8. Allyl isothiocyanate affects the cell cycle of Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Signe Elisabeth Åsberg

    2015-05-01

    Full Text Available Isothiocyanates (ITCs are degradation products of glucosinolates present in members of the Brassicaceae family acting as herbivore repellents and antimicrobial compounds. Recent results indicate that allyl ITC (AITC has a role in defense responses such as glutathione depletion, ROS generation and stomatal closure. In this study we show that exposure to non-lethal concentrations of AITC causes a shift in the cell cycle distribution of Arabidopsis thaliana leading to accumulation of cells in S-phases and a reduced number of cells in non-replicating phases. Furthermore, transcriptional analysis revealed an AITC-induced up-regulation of the gene encoding cyclin-dependent kinase A while several genes encoding mitotic proteins were down-regulated, suggesting an inhibition of mitotic processes. Interestingly, visualization of DNA synthesis indicated that exposure to AITC reduced the rate of DNA replication. Taken together, these results indicate that non-lethal concentrations of AITC induce cells of A. thaliana to enter the cell cycle and accumulate in S-phases, presumably as a part of a defensive response. Thus, this study suggests that AITC has several roles in plant defense and add evidence to the growing data supporting a multifunctional role of glucosinolates and their degradation products in plants.

  9. Combination of ascorbate/epigallocatechin-3-gallate/gemcitabine synergistically induces cell cycle deregulation and apoptosis in mesothelioma cells

    Energy Technology Data Exchange (ETDEWEB)

    Martinotti, Simona [Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte Orientale “Amedeo Avogadro”, viale T. Michel 11, 15121 Alessandria (Italy); Ranzato, Elia, E-mail: ranzato@unipmn.it [Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte Orientale “Amedeo Avogadro”, viale T. Michel 11, 15121 Alessandria (Italy); Parodi, Monica [IRCCS A.O.U. S. Martino-IST, Istituto Nazionale per la Ricerca sul Cancro, 16132 Genova (Italy); DI.ME.S., Università degli Studi di Genova, Via L. Alberti 2, 16132 Genova (Italy); Vitale, Massimo [IRCCS A.O.U. S. Martino-IST, Istituto Nazionale per la Ricerca sul Cancro, 16132 Genova (Italy); Burlando, Bruno [Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte Orientale “Amedeo Avogadro”, viale T. Michel 11, 15121 Alessandria (Italy)

    2014-01-01

    Malignant mesothelioma (MMe) is a poor-prognosis tumor in need of innovative therapies. In a previous in vivo study, we showed synergistic anti-MMe properties of the ascorbate/epigallocatechin-3-gallate/gemcitabine combination. We have now focused on the mechanism of action, showing the induction of apoptosis and cell cycle arrest through measurements of caspase 3, intracellular Ca{sup 2+}, annexin V, and DNA content. StellArray™ PCR technology and Western immunoblotting revealed DAPK2-dependent apoptosis, upregulation of cell cycle promoters, downregulation of cell cycle checkpoints and repression of NFκB expression. The complex of data indicates that the mixture is synergistic in inducing cell cycle deregulation and non-inflammatory apoptosis, suggesting its possible use in MMe treatment. - Highlights: • Ascorbate/epigallocathechin-gallate/gemcitabine has been tested on mesothelioma cells • A synergistic mechanism has been shown for cell cycle arrest and apoptosis • PCR-array analysis has revealed the de-regulation of apoptosis and cell cycle genes • Maximum upregulation has been found for the Death-Associated Protein Kinase-2 gene • Data suggest that the mixture could be used as a clinical treatment.

  10. MiR-7 triggers cell cycle arrest at the G1/S transition by targeting multiple genes including Skp2 and Psme3.

    Directory of Open Access Journals (Sweden)

    Noelia Sanchez

    Full Text Available MiR-7 acts as a tumour suppressor in many cancers and abrogates proliferation of CHO cells in culture. In this study we demonstrate that miR-7 targets key regulators of the G1 to S phase transition, including Skp2 and Psme3, to promote increased levels of p27(KIP and temporary growth arrest of CHO cells in the G1 phase. Simultaneously, the down-regulation of DNA repair-specific proteins via miR-7 including Rad54L, and pro-apoptotic regulators such as p53, combined with the up-regulation of anti-apoptotic factors like p-Akt, promoted cell survival while arrested in G1. Thus miR-7 can co-ordinate the levels of multiple genes and proteins to influence G1 to S phase transition and the apoptotic response in order to maintain cellular homeostasis. This work provides further mechanistic insight into the role of miR-7 as a regulator of cell growth in times of cellular stress.

  11. Identification of Plagl1/Zac1 binding sites and target genes establishes its role in the regulation of extracellular matrix genes and the imprinted gene network.

    Science.gov (United States)

    Varrault, Annie; Dantec, Christelle; Le Digarcher, Anne; Chotard, Laëtitia; Bilanges, Benoit; Parrinello, Hugues; Dubois, Emeric; Rialle, Stéphanie; Severac, Dany; Bouschet, Tristan; Journot, Laurent

    2017-10-13

    PLAGL1/ZAC1 undergoes parental genomic imprinting, is paternally expressed, and is a member of the imprinted gene network (IGN). It encodes a zinc finger transcription factor with anti-proliferative activity and is a candidate tumor suppressor gene on 6q24 whose expression is frequently lost in various neoplasms. Conversely, gain of PLAGL1 function is responsible for transient neonatal diabetes mellitus, a rare genetic disease that results from defective pancreas development. In the present work, we showed that Plagl1 up-regulation was not associated with DNA damage-induced cell cycle arrest. It was rather associated with physiological cell cycle exit that occurred with contact inhibition, growth factor withdrawal, or cell differentiation. To gain insights into Plagl1 mechanism of action, we identified Plagl1 target genes by combining chromatin immunoprecipitation and genome-wide transcriptomics in transfected cell lines. Plagl1-elicited gene regulation correlated with multiple binding to the proximal promoter region through a GC-rich motif. Plagl1 target genes included numerous genes involved in signaling, cell adhesion, and extracellular matrix composition, including collagens. Plagl1 targets also included 22% of the 409 genes that make up the IGN. Altogether, this work identified Plagl1 as a transcription factor that coordinated the regulation of a subset of IGN genes and controlled extracellular matrix composition. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  12. Do lipids shape the eukaryotic cell cycle?

    Science.gov (United States)

    Furse, Samuel; Shearman, Gemma C

    2018-01-01

    Successful passage through the cell cycle presents a number of structural challenges to the cell. Inceptive studies carried out in the last five years have produced clear evidence of modulations in the lipid profile (sometimes referred to as the lipidome) of eukaryotes as a function of the cell cycle. This mounting body of evidence indicates that lipids play key roles in the structural transformations seen across the cycle. The accumulation of this evidence coincides with a revolution in our understanding of how lipid composition regulates a plethora of biological processes ranging from protein activity through to cellular signalling and membrane compartmentalisation. In this review, we discuss evidence from biological, chemical and physical studies of the lipid fraction across the cell cycle that demonstrate that lipids are well-developed cellular components at the heart of the biological machinery responsible for managing progress through the cell cycle. Furthermore, we discuss the mechanisms by which this careful control is exercised. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

  13. Alteration of cell cycle progression by Sindbis virus infection

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Ruirong; Saito, Kengo [Department of Molecular Virology, Graduate School of Medicine, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chiba 260-8670 (Japan); Isegawa, Naohisa [Laboratory Animal Center, Graduate School of Medicine, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chiba 260-8670 (Japan); Shirasawa, Hiroshi, E-mail: sirasawa@faculty.chiba-u.jp [Department of Molecular Virology, Graduate School of Medicine, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chiba 260-8670 (Japan)

    2015-07-10

    We examined the impact of Sindbis virus (SINV) infection on cell cycle progression in a cancer cell line, HeLa, and a non-cancerous cell line, Vero. Cell cycle analyses showed that SINV infection is able to alter the cell cycle progression in both HeLa and Vero cells, but differently, especially during the early stage of infection. SINV infection affected the expression of several cell cycle regulators (CDK4, CDK6, cyclin E, p21, cyclin A and cyclin B) in HeLa cells and caused HeLa cells to accumulate in S phase during the early stage of infection. Monitoring SINV replication in HeLa and Vero cells expressing cell cycle indicators revealed that SINV which infected HeLa cells during G{sub 1} phase preferred to proliferate during S/G{sub 2} phase, and the average time interval for viral replication was significantly shorter in both HeLa and Vero cells infected during G{sub 1} phase than in cells infected during S/G{sub 2} phase. - Highlights: • SINV infection was able to alter the cell cycle progression of infected cancer cells. • SINV infection can affect the expression of cell cycle regulators. • SINV infection exhibited a preference for the timing of viral replication among the cell cycle phases.

  14. Alteration of cell cycle progression by Sindbis virus infection

    International Nuclear Information System (INIS)

    Yi, Ruirong; Saito, Kengo; Isegawa, Naohisa; Shirasawa, Hiroshi

    2015-01-01

    We examined the impact of Sindbis virus (SINV) infection on cell cycle progression in a cancer cell line, HeLa, and a non-cancerous cell line, Vero. Cell cycle analyses showed that SINV infection is able to alter the cell cycle progression in both HeLa and Vero cells, but differently, especially during the early stage of infection. SINV infection affected the expression of several cell cycle regulators (CDK4, CDK6, cyclin E, p21, cyclin A and cyclin B) in HeLa cells and caused HeLa cells to accumulate in S phase during the early stage of infection. Monitoring SINV replication in HeLa and Vero cells expressing cell cycle indicators revealed that SINV which infected HeLa cells during G 1 phase preferred to proliferate during S/G 2 phase, and the average time interval for viral replication was significantly shorter in both HeLa and Vero cells infected during G 1 phase than in cells infected during S/G 2 phase. - Highlights: • SINV infection was able to alter the cell cycle progression of infected cancer cells. • SINV infection can affect the expression of cell cycle regulators. • SINV infection exhibited a preference for the timing of viral replication among the cell cycle phases

  15. Cell cycle effects of L-sulforaphane, a major antioxidant from cruciferous vegetables: The role of the anaphase promoting complex.

    Science.gov (United States)

    Shelley, Zhaoping; Royce, Simon G; Ververis, Katherine; Karagiannis, Tom C

    2014-01-01

    L-sulforaphane (LSF) is a natural isothiocyanate found in cruciferous vegetables particularly broccoli. LSF has been identified as a potent antioxidant and anti-cancer agent and is widely known to regulate phase II detoxifying enzymes and induce cell cycle arrest or apoptosis in malignant cells in vitro and in vivo. Previous studies have found significant G2/M cell cycle arrest in response to LSF in various model of cancer and results have mainly been attributed to increased cyclin B1 protein levels and increased p21expression. Using genome-wide mRNA-Seq analysis we provide insights into the molecular mechanisms of action of LSF to identify a key pathway in cell cycle progression - the role of the anaphase promoting complex (APC) pathway. We evaluated gene expression changes in human erythroleukemic K562 cells following treatment with 15 μM LSF for 48h and compared them to immortalized human keratinocytes, human microvascular endothelial cells (HMEC-1) cells and normal human umbilical endothelial cells (HUVEC). We identified disparate gene expression changes in response to LSF between malignant and normal cells and immortalized cell lines. The results highlight significant down-regulation of kinase CDK1 which is suggestive that the existence and activity of APC/CDC20 complex will be inhibited along with its associated down-stream degradation of key cell cycle regulators preventing cell cycle progression from mitotic exit.

  16. Apoptosis Induction by Polygonum minus is related to antioxidant capacity, alterations in expression of apoptotic-related genes, and S-phase cell cycle arrest in HepG2 cell line.

    Science.gov (United States)

    Mohd Ghazali, Mohd Alfazari; Al-Naqeb, Ghanya; Krishnan Selvarajan, Kesavanarayanan; Hazizul Hasan, Mizaton; Adam, Aishah

    2014-01-01

    Polygonum minus (Polygonaceae) is a medicinal herb distributed throughout eastern Asia. The present study investigated antiproliferative effect of P. minus and its possible mechanisms. Four extracts (petroleum ether, methanol, ethyl acetate, and water) were prepared by cold maceration. Extracts were subjected to phytochemical screening, antioxidant, and antiproliferative assays; the most bioactive was fractionated using vacuum liquid chromatography into seven fractions (F1-F7). Antioxidant activity was measured via total phenolic content (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and ferric reducing antioxidant power (FRAP) assays. Antiproliferative activity was evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Most active fraction was tested for apoptosis induction and cell cycle arrest in HepG2 cells using flow cytometry and confocal microscopy. Apoptotic-related gene expression was studied by RT-PCR. Ethyl acetate extract was bioactive in initial assays. Its fraction, F7, exhibited highest antioxidant capacity (TPC; 113.16 ± 6.2 mg GAE/g extract, DPPH; EC50: 30.5 ± 3.2 μg/mL, FRAP; 1169 ± 20.3 μmol Fe (II)/mg extract) and selective antiproliferative effect (IC50: 25.75 ± 1.5 μg/mL). F7 induced apoptosis in concentration- and time-dependent manner and caused cell cycle arrest at S-phase. Upregulation of proapoptotic genes (Bax, p53, and caspase-3) and downregulation of antiapoptotic gene, Bcl-2, were observed. In conclusion, F7 was antiproliferative to HepG2 cells by inducing apoptosis, cell cycle arrest, and via antioxidative effects.

  17. MiR-107 and MiR-185 can induce cell cycle arrest in human non small cell lung cancer cell lines.

    Directory of Open Access Journals (Sweden)

    Yukari Takahashi

    Full Text Available BACKGROUND: MicroRNAs (miRNAs are short single stranded noncoding RNAs that suppress gene expression through either translational repression or degradation of target mRNAs. The annealing between messenger RNAs and 5' seed region of miRNAs is believed to be essential for the specific suppression of target gene expression. One miRNA can have several hundred different targets in a cell. Rapidly accumulating evidence suggests that many miRNAs are involved in cell cycle regulation and consequentially play critical roles in carcinogenesis. METHODOLOGY/PRINCIPAL FINDINGS: Introduction of synthetic miR-107 or miR-185 suppressed growth of the human non-small cell lung cancer cell lines. Flow cytometry analysis revealed these miRNAs induce a G1 cell cycle arrest in H1299 cells and the suppression of cell cycle progression is stronger than that by Let-7 miRNA. By the gene expression analyses with oligonucleotide microarrays, we find hundreds of genes are affected by transfection of these miRNAs. Using miRNA-target prediction analyses and the array data, we listed up a set of likely targets of miR-107 and miR-185 for G1 cell cycle arrest and validate a subset of them using real-time RT-PCR and immunoblotting for CDK6. CONCLUSIONS/SIGNIFICANCE: We identified new cell cycle regulating miRNAs, miR-107 and miR-185, localized in frequently altered chromosomal regions in human lung cancers. Especially for miR-107, a large number of down-regulated genes are annotated with the gene ontology term 'cell cycle'. Our results suggest that these miRNAs may contribute to regulate cell cycle in human malignant tumors.

  18. Vitamins K2, K3 and K5 exert in vivo antitumor effects on hepatocellular carcinoma by regulating the expression of G1 phase-related cell cycle molecules.

    Science.gov (United States)

    Kuriyama, Shigeki; Hitomi, Misuzu; Yoshiji, Hitoshi; Nonomura, Takako; Tsujimoto, Tatsuhiro; Mitoro, Akira; Akahane, Takami; Ogawa, Mutsumi; Nakai, Seiji; Deguchi, Akihiro; Masaki, Tsutomu; Uchida, Naohito

    2005-08-01

    A number of studies have shown that various vitamins K, specifically vitamin K2, possessed antitumor activity on various types of rodent- and human-derived neoplastic cell lines. However, there are only a small number of reports demonstrating in vivo antitumor effects of vitamins K. Furthermore, the mechanism of antitumor effects of vitamins K still remains to be examined. In the present study, we examined the antitumor effects of vitamins K2, K3 and K5 on PLC/PRF/5 human hepatocellular carcinoma (HCC) cells in vivo. Furthermore, to examine the mechanism of antitumor actions of these vitamins K, mRNA expression levels of various G1 phase-related cell cycle molecules were evaluated by using a real-time reverse transcription-polymerase chain reaction (RT-PCR) method. HCC-bearing animals were produced by implanting PLC/PRF/5 cells subcutaneously into athymic nude mice, and drinking water containing vitamin K2, K3 or K5 was given to the animals. Treatments with vitamins K2, K3 and K5 were shown to markedly inhibit the growth of HCC tumors. To examine the mechanism of in vivo antitumor effects of vitamins K, total RNA was extracted from HCC tumors, and the expression of G1 phase-related cell cycle molecules was quantitatively examined. Real-time RT-PCR demonstrated that the expression of the cell cycle-driving molecule, cyclin-dependent kinase 4 (Cdk4), in HCC was significantly reduced by the treatments with vitamin K2, K3 and K5. Conversely, the expression of the cell cycle-suppressing molecules, Cdk inhibitor p16INK4a and retinoblastoma, in HCC was significantly enhanced by the treatments with vitamins K2, K3 and K5. These results indicate that vitamins K2, K3 and K5 exert antitumor effects on HCC by regulating the expression of G1 phase-related cell cycle molecules. These results also indicate that vitamins K2, K3 and K5 may be useful agents for the treatment of patients with HCC.

  19. Dramatic repositioning of c-Myb to different promoters during the cell cycle observed by combining cell sorting with chromatin immunoprecipitation.

    Directory of Open Access Journals (Sweden)

    Anita M Quintana

    2011-02-01

    Full Text Available The c-Myb transcription factor is a critical regulator of proliferation and stem cell differentiation, and mutated alleles of c-Myb are oncogenic, but little is known about changes in c-Myb activity during the cell cycle. To map the association of c-Myb with specific target genes during the cell cycle, we developed a novel Fix-Sort-ChIP approach, in which asynchronously growing cells were fixed with formaldehyde, stained with Hoechst 33342 and separated into different cell cycle fractions by flow sorting, then processed for chromatin immunoprecipitation (ChIP assays. We found that c-Myb actively repositions, binding to some genes only in specific cell cycle phases. In addition, the specificity of c-Myb is dramatically different in small subpopulations of cells, for example cells in the G2/M phase of the cell cycle, than in the bulk population. The repositioning of c-Myb during the cell cycle is not due to changes in its expression and also occurs with ectopically expressed, epitope-tagged versions of c-Myb. The repositioning occurs in established cell lines, in primary human CD34+ hematopoietic progenitors and in primary human acute myeloid leukemia cells. The combination of fixation, sorting and ChIP analysis sheds new light on the dynamic nature of gene regulation during the cell cycle and provides a new type of tool for the analysis of gene regulation in small subsets of cells, such as cells in a specific phase of the cell cycle.

  20. Cell cycle- and cancer-associated gene networks activated by Dsg2: evidence of cystatin A deregulation and a potential role in cell-cell adhesion.

    Directory of Open Access Journals (Sweden)

    Abhilasha Gupta

    Full Text Available Cell-cell adhesion is paramount in providing and maintaining multicellular structure and signal transmission between cells. In the skin, disruption to desmosomal regulated intercellular connectivity may lead to disorders of keratinization and hyperproliferative disease including cancer. Recently we showed transgenic mice overexpressing desmoglein 2 (Dsg2 in the epidermis develop hyperplasia. Following microarray and gene network analysis, we demonstrate that Dsg2 caused a profound change in the transcriptome of keratinocytes in vivo and altered a number of genes important in epithelial dysplasia including: calcium-binding proteins (S100A8 and S100A9, members of the cyclin protein family, and the cysteine protease inhibitor cystatin A (CSTA. CSTA is deregulated in several skin cancers, including squamous cell carcinomas (SCC and loss of function mutations lead to recessive skin fragility disorders. The microarray results were confirmed by qPCR, immunoblotting, and immunohistochemistry. CSTA was detected at high level throughout the newborn mouse epidermis but dramatically decreased with development and was detected predominantly in the differentiated layers. In human keratinocytes, knockdown of Dsg2 by siRNA or shRNA reduced CSTA expression. Furthermore, siRNA knockdown of CSTA resulted in cytoplasmic localization of Dsg2, perturbed cytokeratin 14 staining and reduced levels of desmoplakin in response to mechanical stretching. Both knockdown of either Dsg2 or CSTA induced loss of cell adhesion in a dispase-based assay and the effect was synergistic. Our findings here offer a novel pathway of CSTA regulation involving Dsg2 and a potential crosstalk between Dsg2 and CSTA that modulates cell adhesion. These results further support the recent human genetic findings that loss of function mutations in the CSTA gene result in skin fragility due to impaired cell-cell adhesion: autosomal-recessive exfoliative ichthyosis or acral peeling skin syndrome.

  1. Gene regulation by growth factors

    International Nuclear Information System (INIS)

    Metz, R.; Gorham, J.; Siegfried, Z.; Leonard, D.; Gizang-Ginsberg, E.; Thompson, M.A.; Lawe, D.; Kouzarides, T.; Vosatka, R.; MacGregor, D.; Jamal, S.; Greenberg, M.E.; Ziff, E.B.

    1988-01-01

    To coordinate the proliferation and differentiation of diverse cell types, cells of higher eukaryotes communicate through the release of growth factors. These peptides interact with specific transmembrane receptors of other cells and thereby generate intracellular messengers. The many changes in cellular physiology and activity that can be induced by growth factors imply that growth factor-induced signals can reach the nucleus and control gene activity. Moreover, current evidence also suggests that unregulated signaling along such pathways can induce aberrant proliferation and the formation of tumors. This paper reviews investigations of growth factor regulation of gene expression conducted by the authors' laboratory

  2. Cell cycle synchronization and analysis of apoptosis-related gene in skin fibroblasts from domestic cat (Felis silvestris catus) and kodkod (Leopardus guigna).

    Science.gov (United States)

    Veraguas, D; Gallegos, P F; Castro, F O; Rodriguez-Alvarez, L

    2017-10-01

    The kodkod population is in constant decrease and the somatic cell nuclear transfer (SCNT) might help to preserve the genetic pool of this species. The cell cycle synchronization of donor cells plays a crucial role in SCNT. The objective of this research was to evaluate two different methods for quiescence induction, serum starvation (SS) and contact inhibition (CI), both for 1, 3 and 5 days, on skin fibroblast from domestic cat and kodkod. Flow cytometry analysis revealed that in domestic cat, SS and CI, both at 3 and 5 days, increased the percentage of fibroblasts in G0/G1 compared to growing cells (GC) (p kodkod, only SS for 3 and 5 days and CI for 1 and 3 days increased the percentage of fibroblasts in G0/G1 compared to GC (p kodkod (p kodkod fibroblasts, BAX/BCL2 ratio was increased in CI at 3 and 5 days compared to SS at 3 and 5 days (p kodkod fibroblasts SS for 5 days and CI after 3 days might have a negative impact on cellular viability. According to these results, we suggest SS for 3 days for cell cycle synchronization in kodkod fibroblasts. © 2017 Blackwell Verlag GmbH.

  3. Overexpression of a novel cell cycle regulator ecdysoneless in breast cancer: a marker of poor prognosis in HER2/neu-overexpressing breast cancer patients.

    Science.gov (United States)

    Zhao, Xiangshan; Mirza, Sameer; Alshareeda, Alaa; Zhang, Ying; Gurumurthy, Channabasavaiah Basavaraju; Bele, Aditya; Kim, Jun Hyun; Mohibi, Shakur; Goswami, Monica; Lele, Subodh M; West, William; Qiu, Fang; Ellis, Ian O; Rakha, Emad A; Green, Andrew R; Band, Hamid; Band, Vimla

    2012-07-01

    Uncontrolled proliferation is one of the hallmarks of breast cancer. We have previously identified the human Ecd protein (human ortholog of Drosophila Ecdysoneless, hereafter called Ecd) as a novel promoter of mammalian cell cycle progression, a function related to its ability to remove the repressive effects of Rb-family tumor suppressors on E2F transcription factors. Given the frequent dysregulation of cell cycle regulatory components in human cancer, we used immunohistochemistry of paraffin-embedded tissues to examine Ecd expression in normal breast tissue versus tissues representing increasing breast cancer progression. Initial studies of a smaller cohort without outcomes information showed that Ecd expression was barely detectable in normal breast tissue and in hyperplasia of breast, but high levels of Ecd were detected in benign breast hyperplasia, ductal carcinoma in situ (DCIS) and infiltrating ductal carcinoma (IDCs) of the breast. In this cohort of 104 IDC patients, Ecd expression levels showed a positive correlation with higher grade (P=0.04). Further analyses of Ecd expression using a larger, independent cohort (954) confirmed these results, with a strong positive correlation of elevated Ecd expression with higher histological grade (P=0.013), mitotic index (P=0.032), and Nottingham Prognostic Index score (P=0.014). Ecd expression was positively associated with HER2/neu (P=0.002) overexpression, a known marker of poor prognosis in breast cancer. Significantly, increased Ecd expression showed a strong positive association with shorter breast cancer specific survival (BCSS) (P=0.008) and disease-free survival (DFS) (P=0.003) in HER2/neu overexpressing patients. Taken together, our results reveal Ecd as a novel marker for breast cancer progression and show that levels of Ecd expression predict poorer survival in Her2/neu overexpressing breast cancer patients.

  4. microRNA-365, down-regulated in colon cancer, inhibits cell cycle progression and promotes apoptosis of colon cancer cells by probably targeting Cyclin D1 and Bcl-2.

    Science.gov (United States)

    Nie, Jing; Liu, Lin; Zheng, Wei; Chen, Lin; Wu, Xin; Xu, Yingxin; Du, Xiaohui; Han, Weidong

    2012-01-01

    Deregulated microRNAs participate in carcinogenesis and cancer progression, but their roles in cancer development remain unclear. In this study, miR-365 expression was found to be downregulated in human colon cancer tissues as compared with that in matched non-neoplastic mucosa tissues, and its downregulation was correlated with cancer progression and poor survival in colon cancer patients. Functional studies revealed that restoration of miR-365 expression inhibited cell cycle progression, promoted 5-fluorouracil-induced apoptosis and repressed tumorigenicity in colon cancer cell lines. Furthermore, bioinformatic prediction and experimental validation were used to identify miR-365 target genes and indicated that the antitumor effects of miR-365 were probably mediated by its targeting and repression of Cyclin D1 and Bcl-2 expression, thus inhibiting cell cycle progression and promoting apoptosis. These results suggest that downregulation of miR-365 in colon cancer may have potential applications in prognosis prediction and gene therapy in colon cancer patients.

  5. Benzophenone-1 stimulated the growth of BG-1 ovarian cancer cells by cell cycle regulation via an estrogen receptor alpha-mediated signaling pathway in cellular and xenograft mouse models

    International Nuclear Information System (INIS)

    Park, Min-Ah; Hwang, Kyung-A; Lee, Hye-Rim; Yi, Bo-Rim; Jeung, Eui-Bae; Choi, Kyung-Chul

    2013-01-01

    Highlights: ► BP-1 induced cell growth was reversed by an ER antagonist in BG-1 cells. ► BP-1 up-regulated the mRNA expression of cyclin D1. ► Up-regulation of cyclin D1 by BP-1 was reversed by an ER antagonist. ► BP-1 is a potential endocrine disruptor that exerts estrogenic effects. - Abstract: 2,4-Dihydroxybenzophenone (benzophenone-1; BP-1) is an UV stabilizer primarily used to prevent polymer degradation and deterioration in quality due to UV irradiation. Recently, BP-1 has been reported to bioaccumulate in human bodies by absorption through the skin and has the potential to induce health problems including endocrine disruption. In the present study, we examined the xenoestrogenic effect of BP-1 on BG-1 human ovarian cancer cells expressing estrogen receptors (ERs) and relevant xenografted animal models in comparison with 17-β estradiol (E2). In in vitro cell viability assay, BP-1 (10 −8 –10 −5 M) significantly increased BG-1 cell growth the way E2 did. The mechanism underlying the BG-1 cell proliferation was proved to be related with the up-regulation of cyclin D1, a cell cycle progressor, by E2 or BP-1. Both BP-1 and E2 induced cell growth and up-regulation of cyclin D1 were reversed by co-treatment with ICI 182,780, an ER antagonist, suggesting that BP-1 may mediate the cancer cell proliferation via an ER-dependent pathway like E2. On the other hand, the expression of p21, a regulator of cell cycle progression at G 1 phase, was not altered by BP-1 though it was down-regulated by E2. In xenograft mouse models transplanted with BG-1 cells, BP-1 or E2 treatment significantly increased the tumor mass formation compared to a vehicle (corn oil) within 8 weeks. In histopathological analysis, the tumor sections of E2 or BP-1 group displayed extensive cell formations with high density and disordered arrangement, which were supported by the increased number of BrdUrd positive nuclei and the over-expression of cyclin D1 protein. Taken together, these

  6. A retinoblastoma orthologue is a major regulator of S-phase, mitotic, and developmental gene expression in Dictyostelium.

    Directory of Open Access Journals (Sweden)

    Kimchi Strasser

    Full Text Available The retinoblastoma tumour suppressor, Rb, has two major functions. First, it represses genes whose products are required for S-phase entry and progression thus stabilizing cells in G1. Second, Rb interacts with factors that induce cell-cycle exit and terminal differentiation. Dictyostelium lacks a G1 phase in its cell cycle but it has a retinoblastoma orthologue, rblA.Using microarray analysis and mRNA-Seq transcriptional profiling, we show that RblA strongly represses genes whose products are involved in S phase and mitosis. Both S-phase and mitotic genes are upregulated at a single point in late G2 and again in mid-development, near the time when cell cycling is reactivated. RblA also activates a set of genes unique to slime moulds that function in terminal differentiation.Like its mammalian counterpart Dictyostelium, RblA plays a dual role, regulating cell-cycle progression and transcriptional events leading to terminal differentiation. In the absence of a G1 phase, however, RblA functions in late G2 controlling the expression of both S-phase and mitotic genes.

  7. MiR-210 disturbs mitotic progression through regulating a group of mitosis-related genes.

    Science.gov (United States)

    He, Jie; Wu, Jiangbin; Xu, Naihan; Xie, Weidong; Li, Mengnan; Li, Jianna; Jiang, Yuyang; Yang, Burton B; Zhang, Yaou

    2013-01-07

    MiR-210 is up-regulated in multiple cancer types but its function is disputable and further investigation is necessary. Using a bioinformatics approach, we identified the putative target genes of miR-210 in hypoxia-induced CNE cells from genome-wide scale. Two functional gene groups related to cell cycle and RNA processing were recognized as the major targets of miR-210. Here, we investigated the molecular mechanism and biological consequence of miR-210 in cell cycle regulation, particularly mitosis. Hypoxia-induced up-regulation of miR-210 was highly correlated with the down-regulation of a group of mitosis-related genes, including Plk1, Cdc25B, Cyclin F, Bub1B and Fam83D. MiR-210 suppressed the expression of these genes by directly targeting their 3'-UTRs. Over-expression of exogenous miR-210 disturbed mitotic progression and caused aberrant mitosis. Furthermore, miR-210 mimic with pharmacological doses reduced tumor formation in a mouse metastatic tumor model. Taken together, these results implicate that miR-210 disturbs mitosis through targeting multi-genes involved in mitotic progression, which may contribute to its inhibitory role on tumor formation.

  8. The human papillomavirus type 11 and 16 E6 proteins modulate the cell-cycle regulator and transcription cofactor TRIP-Br1

    International Nuclear Information System (INIS)

    Gupta, Sanjay; Takhar, Param Parkash S; Degenkolbe, Roland; Heng Koh, Choon; Zimmermann, Holger; Maolin Yang, Christopher; Guan Sim, Khe; I-Hong Hsu, Stephen; Bernard, Hans-Ulrich

    2003-01-01

    The genital human papillomaviruses (HPVs) are a taxonomic group including HPV types that preferentially cause genital and laryngeal warts ('low-risk types'), such as HPV-6 and HPV-11, or cancer of the cervix and its precursor lesions ('high-risk types'), such as HPV-16. The transforming processes induced by these viruses depend on the proteins E5, E6, and E7. Among these oncoproteins, the E6 protein stands out because it supports a particularly large number of functions and interactions with cellular proteins, some of which are specific for the carcinogenic HPVs, while others are shared among low- and high-risk HPVs. Here we report yeast two-hybrid screens with HPV-6 and -11 E6 proteins that identified TRIP-Br1 as a novel cellular target. TRIP-Br1 was recently detected by two research groups, which described two separate functions, namely that of a transcriptional integrator of the E2F1/DP1/RB cell-cycle regulatory pathway (and then named TRIP-Br1), and that of an antagonist of the cyclin-dependent kinase suppression of p16INK4a (and then named p34SEI-1). We observed that TRIP-Br1 interacts with low- and high-risk HPV E6 proteins in yeast, in vitro and in mammalian cell cultures. Transcription activation of a complex consisting of E2F1, DP1, and TRIP-Br1 was efficiently stimulated by both E6 proteins. TRIP-Br1 has an LLG E6 interaction motif, which contributed to the binding of E6 proteins. Apparently, E6 does not promote degradation of TRIP-Br1. Our observations imply that the cell-cycle promoting transcription factor E2F1/DP1 is dually targeted by HPV oncoproteins, namely (i) by interference of the E7 protein with repression by RB, and (ii) by the transcriptional cofactor function of the E6 protein. Our data reveal the natural context of the transcription activator function of E6, which has been predicted without knowledge of the E2F1/DP1/TRIP-Br/E6 complex by studying chimeric constructs, and add a function to the limited number of transforming properties shared

  9. Cell cycle regulation by the Wee1 Inhibitor PD0166285, Pyrido [2,3-d] pyimidine, in the B16 mouse melanoma cell line

    International Nuclear Information System (INIS)

    Hashimoto, Osamu; Shinkawa, Masako; Torimura, Takuji; Nakamura, Toru; Selvendiran, Karuppaiyah; Sakamoto, Masaharu; Koga, Hironori; Ueno, Takato; Sata, Michio

    2006-01-01

    Wee1 kinase plays a critical role in maintaining G2 arrest through its inhibitory phosphorylation of cdc2. In previous reports, a pyridopyrimidine molecule PD0166285 was identified to inhibit Wee1 activity at nanomolar concentrations. This G2 checkpoint abrogation by PD0166285 was demonstrated to kill cancer cells, there at a toxic highest dose of 0.5 μM in some cell lines for exposure periods of no longer than 6 hours. The deregulated cell cycle progression may have ultimately damaged the cancer cells. We herein report one of the mechanism by which PD0166285 leads to cell death in the B16 mouse melanoma cell line. Tumor cell proliferation was determined by counting cell numbers. Cell cycle distribution was determined by flow cytometry. Morphogenesis analysis such as microtubule stabilization, Wee1 distribution, and cyclin B location were observed by immunofluorescence confocal microscopy. An immunoblot analysis of cdc2-Tyr15, cyclin D, E, p16, 21, 27, and Rb. A real-time PCR of the mRNA of cyclin D were completed. In our experiment, B16 cells also dramatically abrogated the G2 checkpoint and were found to arrest in the early G1 phase by treatment with 0.5 μM for 4 hours observed by flow cytometry. Cyclin D mRNA decreased within 4 hours observed by Real-time PCR. Rb was dephosphrylated for 24 hours. However, B16 cells did not undergo cell death after 0.5 μM treatment for 24 hours. Immnofluoscence microscopy showed that the cells become round and small in the morphogenesis. More interesting phenomena were that microtubule stabilization was blocked, and Wee1 distribution was restricted after treatment for 4 hours. We analyzed the effect of Wee1 inhibitor PD0166285 described first by Wang in the G2 transition in the B16 melanoma cell line. The inhibitor PD0166285 abrogated G2/M checkpoint inducing early cell division. Moreover, we found that the treatment of cells with the inhibitor is related to microtubule stabilization and decrease in cyclin D transcription

  10. Connecting the nucleolus to the cell cycle and human disease.

    Science.gov (United States)

    Tsai, Robert Y L; Pederson, Thoru

    2014-08-01

    Long known as the center of ribosome synthesis, the nucleolus is connected to cell cycle regulation in more subtle ways. One is a surveillance system that reacts promptly when rRNA synthesis or processing is impaired, halting cell cycle progression. Conversely, the nucleolus also acts as a first-responder to growth-related stress signals. Here we review emerging concepts on how these "infraribosomal" links between the nucleolus and cell cycle progression operate in both forward and reverse gears. We offer perspectives on how new cancer therapeutic designs that target this infraribosomal mode of cell growth control may shape future clinical progress. © FASEB.

  11. Cell cycle arrest in plants: what distinguishes quiescence, dormancy and differentiated G1?

    Science.gov (United States)

    Velappan, Yazhini; Signorelli, Santiago; Considine, Michael J

    2017-10-17

    Quiescence is a fundamental feature of plant life, which enables plasticity, renewal and fidelity of the somatic cell line. Cellular quiescence is defined by arrest in a particular phase of the cell cycle, typically G1 or G2; however, the regulation of quiescence and proliferation can also be considered across wider scales in space and time. As such, quiescence is a defining feature of plant development and phenology, from meristematic stem cell progenitors to terminally differentiated cells, as well as dormant or suppressed seeds and buds. While the physiology of each of these states differs considerably, each is referred to as 'cell cycle arrest' or 'G1 arrest'. Here the physiology and molecular regulation of (1) meristematic quiescence, (2) dormancy and (3) terminal differentiation (cell cycle exit) are considered in order to determine whether and how the molecular decisions guiding these nuclear states are distinct. A brief overview of the canonical cell cycle regulators is provided, and the genetic and genomic, as well as physiological, evidence is considered regarding two primary questions: (1) Are the canonical cell cycle regulators superior or subordinate in the regulation of quiescence? (2) Are these three modes of quiescence governed by distinct molecular controls? Meristematic quiescence, dormancy and terminal differentiation are each predominantly characterized by G1 arrest but regulated distinctly, at a level largely superior to the canonical cell cycle. Meristematic quiescence is intrinsically linked to non-cell-autonomous regulation of meristem cell identity, and particularly through the influence of ubiquitin-dependent proteolysis, in partnership with reactive oxygen species, abscisic acid and auxin. The regulation of terminal differentiation shares analogous features with meristematic quiescence, albeit with specific activators and a greater role for cytokinin signalling. Dormancy meanwhile appears to be regulated at the level of chromatin

  12. F-box protein FBXO31 is a dedicated checkpoint protein to facilitate cell cycle arrest through activation of regulators in radiation induced DNA damage

    International Nuclear Information System (INIS)

    Santra, Manas Kumar

    2017-01-01

    In response to radiation-induced DNA damage, eukaryotic cells initiate a complex signalling pathway, termed the DNA damage response (DDR), which coordinates cell cycle arrest with DNA repair. Previous study showed that induction of G1 arrest in response to radiation induced DNA damage is minimally a two-step process: a fast p53-independent initiation of G1 arrest mediated by cyclin D1 proteolysis and a slower maintenance of arrest resulting from increased p53 stability. We elucidated the molecular mechanism of slow and fast response of radiation induced DDR. We showed that FBXO31, a member of F-box family proteins, plays important role in DDR induced by ionizing radiation. We show that FBXO31 is responsible for promoting MDM2 degradation following radiation. FBXO31 interacts with and directs the degradation of MDM2 in ATM dependent phosphorylation of MDM2. FBXO31-mediated loss of MDM2 leads to elevated levels of p53, resulting in growth arrest. In cells depleted of FBXO31, MDM2 is not degraded and p53 levels do not increase following genotoxic stress. Thus, FBXO31 is essential for the classic robust increase in p53 levels following DNA damage

  13. QB1 - Stochastic Gene Regulation

    Energy Technology Data Exchange (ETDEWEB)

    Munsky, Brian [Los Alamos National Laboratory

    2012-07-23

    Summaries of this presentation are: (1) Stochastic fluctuations or 'noise' is present in the cell - Random motion and competition between reactants, Low copy, quantization of reactants, Upstream processes; (2) Fluctuations may be very important - Cell-to-cell variability, Cell fate decisions (switches), Signal amplification or damping, stochastic resonances; and (3) Some tools are available to mode these - Kinetic Monte Carlo simulations (SSA and variants), Moment approximation methods, Finite State Projection. We will see how modeling these reactions can tell us more about the underlying processes of gene regulation.

  14. Cytotoxicity of diacetoxyscirpenol is associated with apoptosis by activation of caspase-8 and interruption of cell cycle progression by down-regulation of cdk4 and cyclin B1 in human Jurkat T cells

    International Nuclear Information System (INIS)

    Jun, Do Youn; Kim, Jun Seok; Park, Hae Sun; Song, Woo Sun; Bae, Young Seuk; Kim, Young Ho

    2007-01-01

    To understand the mechanism underlying T-cell toxicity of diacetoxyscirpenol (DAS) from Fusarium sambucinum, its apoptogenic as well as growth retardation activity was investigated in human Jurkat T cells. Exposure to DAS (0.01-0.15 μM) caused apoptotic DNA fragmentation along with caspase-8 activation, Bid cleavage, mitochondrial cytochrome c release, activation of caspase-9 and caspase-3, and PARP degradation, without any alteration in the levels of Fas or FasL. Under these conditions, necrosis was not accompanied. The cytotoxicity of DAS was not blocked by the anti-Fas neutralizing antibody ZB-4. Although the DAS-induced apoptotic events were completely prevented by overexpression of Bcl-xL, the cells overexpressing Bcl-xL were unable to divide in the presence of DAS, resulting from the failure of cell cycle progression possibly due to down-regulation in the protein levels of cdk4 and cyclin B1. The DAS-mediated apoptosis and activation of caspase-8, -9, and -3 were abrogated by either pan-caspase inhibitor (z-VAD-fmk) or caspase-8 inhibitor (z-IETD-fmk). While the DAS-mediated apoptosis and activation of caspase-9 and caspase-3 were slightly suppressed by the mitochondrial permeability transition pore inhibitor (CsA), both caspase-8 activation and Bid cleavage were not affected by CsA. The activated normal peripheral T cells possessed a similar susceptibility to the cytotoxicity of DAS. These results demonstrate that the T-cell toxicity of DAS is attributable to not only apoptosis initiated by caspase-8 activation and subsequent mitochondrion-dependent or -independent activation of caspase cascades, which can be regulated by Bcl-xL, but also interruption of cell cycle progression caused by down-regulation of cdk4 and cyclin B1 proteins

  15. Truncating PREX2 mutations activate its GEF activity and alter gene expression regulation in NRAS-mutant melanoma

    KAUST Repository

    Lissanu Deribe, Yonathan

    2016-03-01

    PREX2 (phosphatidylinositol-3,4,5-triphosphate-dependent Rac-exchange factor 2) is a PTEN (phosphatase and tensin homolog deleted on chromosome 10) binding protein that is significantly mutated in cutaneous melanoma and pancreatic ductal adenocarcinoma. Here, genetic and biochemical analyses were conducted to elucidate the nature and mechanistic basis of PREX2 mutation in melanoma development. By generating an inducible transgenic mouse model we showed an oncogenic role for a truncating PREX2 mutation (PREX2E824*) in vivo in the context of mutant NRAS. Using integrative cross-species gene expression analysis, we identified deregulated cell cycle and cytoskeleton organization as significantly perturbed biological pathways in PREX2 mutant tumors. Mechanistically, truncation of PREX2 activated its Rac1 guanine nucleotide exchange factor activity, abolished binding to PTEN and activated the PI3K (phosphatidyl inositol 3 kinase)/Akt signaling pathway. We further showed that PREX2 truncating mutations or PTEN deletion induces down-regulation of the tumor suppressor and cell cycle regulator CDKN1C (also known as p57KIP2). This down-regulation occurs, at least partially, through DNA hypomethylation of a differentially methylated region in chromosome 11 that is a known regulatory region for expression of the CDKN1C gene. Together, these findings identify PREX2 as a mediator of NRAS-mutant melanoma development that acts through the PI3K/PTEN/Akt pathway to regulate gene expression of a cell cycle regulator.

  16. Truncating PREX2 mutations activate its GEF activity and alter gene expression regulation in NRAS-mutant melanoma.

    Science.gov (United States)

    Lissanu Deribe, Yonathan; Shi, Yanxia; Rai, Kunal; Nezi, Luigi; Amin, Samir B; Wu, Chia-Chin; Akdemir, Kadir C; Mahdavi, Mozhdeh; Peng, Qian; Chang, Qing Edward; Hornigold, Kirsti; Arold, Stefan T; Welch, Heidi C E; Garraway, Levi A; Chin, Lynda

    2016-03-01

    PREX2 (phosphatidylinositol-3,4,5-triphosphate-dependent Rac-exchange factor 2) is a PTEN (phosphatase and tensin homolog deleted on chromosome 10) binding protein that is significantly mutated in cutaneous melanoma and pancreatic ductal adenocarcinoma. Here, genetic and biochemical analyses were conducted to elucidate the nature and mechanistic basis of PREX2 mutation in melanoma development. By generating an inducible transgenic mouse model we showed an oncogenic role for a truncating PREX2 mutation (PREX2(E824)*) in vivo in the context of mutant NRAS. Using integrative cross-species gene expression analysis, we identified deregulated cell cycle and cytoskeleton organization as significantly perturbed biological pathways in PREX2 mutant tumors. Mechanistically, truncation of PREX2 activated its Rac1 guanine nucleotide exchange factor activity, abolished binding to PTEN and activated the PI3K (phosphatidyl inositol 3 kinase)/Akt signaling pathway. We further showed that PREX2 truncating mutations or PTEN deletion induces down-regulation of the tumor suppressor and cell cycle regulator CDKN1C (also known as p57(KIP2)). This down-regulation occurs, at least partially, through DNA hypomethylation of a differentially methylated region in chromosome 11 that is a known regulatory region for expression of the CDKN1C gene. Together, these findings identify PREX2 as a mediator of NRAS-mutant melanoma development that acts through the PI3K/PTEN/Akt pathway to regulate gene expression of a cell cycle regulator.

  17. Truncating PREX2 mutations activate its GEF activity and alter gene expression regulation in NRAS-mutant melanoma

    KAUST Repository

    Lissanu Deribe, Yonathan; Shi, Yanxia; Rai, Kunal; Nezi, Luigi; Amin, Samir B.; Wu, Chia-Chin; Akdemir, Kadir C.; Mahdavi, Mozhdeh; Peng, Qian; Chang, Qing Edward; Hornigold, Kirsti; Arold, Stefan T.; Welch, Heidi C. E.; Garraway, Levi A.; Chin, Lynda

    2016-01-01

    PREX2 (phosphatidylinositol-3,4,5-triphosphate-dependent Rac-exchange factor 2) is a PTEN (phosphatase and tensin homolog deleted on chromosome 10) binding protein that is significantly mutated in cutaneous melanoma and pancreatic ductal adenocarcinoma. Here, genetic and biochemical analyses were conducted to elucidate the nature and mechanistic basis of PREX2 mutation in melanoma development. By generating an inducible transgenic mouse model we showed an oncogenic role for a truncating PREX2 mutation (PREX2E824*) in vivo in the context of mutant NRAS. Using integrative cross-species gene expression analysis, we identified deregulated cell cycle and cytoskeleton organization as significantly perturbed biological pathways in PREX2 mutant tumors. Mechanistically, truncation of PREX2 activated its Rac1 guanine nucleotide exchange factor activity, abolished binding to PTEN and activated the PI3K (phosphatidyl inositol 3 kinase)/Akt signaling pathway. We further showed that PREX2 truncating mutations or PTEN deletion induces down-regulation of the tumor suppressor and cell cycle regulator CDKN1C (also known as p57KIP2). This down-regulation occurs, at least partially, through DNA hypomethylation of a differentially methylated region in chromosome 11 that is a known regulatory region for expression of the CDKN1C gene. Together, these findings identify PREX2 as a mediator of NRAS-mutant melanoma development that acts through the PI3K/PTEN/Akt pathway to regulate gene expression of a cell cycle regulator.

  18. Control points within the cell cycle

    International Nuclear Information System (INIS)

    Van't Hof, J.

    1984-01-01

    Evidence of the temporal order of chromosomal DNA replication argues favorably for the view that the cell cycle is controlled by genes acting in sequence whose time of expression is determined by mitosis and the amount of nuclear DNA (2C vs 4C) in the cell. Gl and G2 appear to be carbohydrate dependent in that cells starved of either carbohydrate of phosphate fail to make these transitions. Cells deprived of nitrate, however, fail only at Gl to S transition indicating that the controls that operate in G1 differ from those that operate in G2. 46 references, 5 figures

  19. Beta-mangostin from Cratoxylum arborescens activates the intrinsic apoptosis pathway through reactive oxygen species with downregulation of the HSP70 gene in the HL60 cells associated with a G0/G1 cell-cycle arrest.

    Science.gov (United States)

    Omer, Fatima Abdelmutaal Ahmed; Hashim, Najihah Binti Mohd; Ibrahim, Mohamed Yousif; Dehghan, Firouzeh; Yahayu, Maizatulakmal; Karimian, Hamed; Salim, Landa Zeenelabdin Ali; Mohan, Syam

    2017-11-01

    Xanthones are phytochemical compounds found in a number of fruits and vegetables. Characteristically, they are noted to be made of diverse properties based on their biological, biochemical, and pharmacological actions. Accordingly, the apoptosis mechanisms induced by beta-mangostin, a xanthone compound isolated from Cratoxylum arborescens in the human promyelocytic leukemia cell line (HL60) in vitro, were examined in this study. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was done to estimate the cytotoxicity effect of β-mangostin on the HL60 cell line. Acridine orange/propidium iodide and Hoechst 33342 dyes and Annexin V tests were conducted to detect the apoptosis features. Caspase-3 and caspase-9 activities; reactive oxygen species; real-time polymerase chain reaction for Bcl-2, Bax, caspase-3, and caspase-9 Hsp70 genes; and western blot for p53, cytochrome c, and pro- and cleavage-caspase-3 and caspase-9 were assessed to examine the apoptosis mechanism. Cell-cycle analysis conducted revealed that β-mangostin inhibited the growth of HL60 at 58 µM in 24 h. The administration of β-mangostin with HL60 caused cell morphological changes related to apoptosis which increased the number of early and late apoptotic cells. The β-mangostin-catalyzed apoptosis action through caspase-3, caspase-7, and caspase-9 activation overproduced reactive oxygen species which downregulated the expression of antiapoptotic genes Bcl-2 and HSP70. Conversely, the expression of the apoptotic genes Bax, caspase-3, and caspase-9 were upregulated. Meanwhile, at the protein level, β-mangostin activated the formation of cleaved caspase-3 and caspase-9 and also upregulated the p53. β-mangostin arrested the cell cycle at the G 0 /G 1 phase. Overall, the results for β-mangostin showed an antiproliferative effect in HL60 via stopping the cell cycle at the G 0 /G 1 phase and prompted the intrinsic apoptosis pathway.

  20. Functional cooperation between FACT and MCM is coordinated with cell cycle and differential complex formation

    Directory of Open Access Journals (Sweden)

    Lin Chih-Li

    2010-02-01

    Full Text Available Abstract Background Functional cooperation between FACT and the MCM helicase complex constitutes an integral step during DNA replication initiation. However, mode of regulation that underlies the proper functional interaction of FACT and MCM is poorly understood. Methods & Results Here we present evidence indicating that such interaction is coordinated with cell cycle progression and differential complex formation. We first demonstrate the existence of two distinct FACT-MCM subassemblies, FACT-MCM2/4/6/7 and FACT-MCM2/3/4/5. Both complexes possess DNA unwinding activity and are subject to cell cycle-dependent enzymatic regulation. Interestingly, analysis of functional attributes further suggests that they act at distinct, and possibly sequential, steps during origin establishment and replication initiation. Moreover, we show that the phosphorylation profile of the FACT-associated MCM4 undergoes a cell cycle-dependent change, which is directly correlated with the catalytic activity of the FACT-MCM helicase complexes. Finally, at the quaternary structure level, physical interaction between FACT and MCM complexes is generally dependent on persistent cell cycle and further stabilized upon S phase entry. Cessation of mitotic cycle destabilizes the complex formation and likely leads to compromised coordination and activities. Conclusions Together, our results correlate FACT-MCM functionally and temporally with S phase and DNA replication. They further demonstrate that enzymatic activities intrinsically important for DNA replication are tightly controlled at various levels, thereby ensuring proper progression of, as well as exit from, the cell cycle and ultimately euploid gene balance.

  1. Cell-Cycle-Specific Function of p53 in Fanconi Anemia Hematopoietic Stem and Progenitor Cell Proliferation

    Directory of Open Access Journals (Sweden)

    Xiaoli Li

    2018-02-01

    Full Text Available Summary: Overactive p53 has been proposed as an important pathophysiological factor for bone marrow failure syndromes, including Fanconi anemia (FA. Here, we report a p53-dependent effect on hematopoietic stem and progenitor cell (HSPC proliferation in mice deficient for the FA gene Fanca. Deletion of p53 in Fanca−/− mice leads to replicative exhaustion of the hematopoietic stem cell (HSC in transplant recipients. Using Fanca−/− HSCs expressing the separation-of-function mutant p53515C transgene, which selectively impairs the p53 function in apoptosis but keeps its cell-cycle checkpoint activities intact, we show that the p53 cell-cycle function is specifically required for the regulation of Fanca−/− HSC proliferation. Our results demonstrate that p53 plays a compensatory role in preventing FA HSCs from replicative exhaustion and suggest a cautious approach to manipulating p53 signaling as a therapeutic utility in FA. : In this article, Pang and colleagues demonstrate a p53-dependent HSPC proliferation regulation in mice deficient for the Fanca gene in the Fanconi anemia (FA pathway. They show that the p53 cell-cycle function is specifically required for the regulation of FA HSC proliferation. These results suggest that overactive p53 may represent a compensatory checkpoint mechanism for FA HSC proliferation. Keywords: p53, bone marrow failure, Fanconi anemia, hematopoietic stem and progenitor cells, apoptosis, cell cycle, proliferation

  2. Phylogenetic analysis of the Neks reveals early diversification of ciliary-cell cycle kinases.

    Directory of Open Access Journals (Sweden)

    Jeremy D K Parker

    2007-10-01

    Full Text Available NIMA-related kinases (Neks have been studied in diverse eukaryotes, including the fungus Aspergillus and the ciliate Tetrahymena. In the former, a single Nek plays an essential role in cell cycle regulation; in the latter, which has more than 30 Neks in its genome, multiple Neks regulate ciliary length. Mammalian genomes encode an intermediate number of Neks, several of which are reported to play roles in cell cycle regulation and/or localize to centrosomes. Previously, we reported that organisms with cilia typically have more Neks than organisms without cilia, but were unable to establish the evolutionary history of the gene family.We have performed a large-scale analysis of the Nek family using Bayesian techniques, including tests of alternate topologies. We find that the Nek family had already expanded in the last common ancestor of eukaryotes, a ciliated cell which likely expressed at least five Neks. We suggest that Neks played an important role in the common ancestor in regulating cilia, centrioles, and centrosomes with respect to mitotic entry, and that this role continues today in organisms with cilia. Organisms that lack cilia generally show a reduction in the number of Nek clades represented, sometimes associated with lineage specific expansion of a single clade, as has occurred in the plants.This is the first rigorous phylogenetic analysis of a kinase family across a broad array of phyla. Our findings provide a coherent framework for the study of Neks and their roles in coordinating cilia and cell cycle progression.

  3. Cell cycle-dependent induction of autophagy, mitophagy and reticulophagy.

    Science.gov (United States)

    Tasdemir, Ezgi; Maiuri, M Chiara; Tajeddine, Nicolas; Vitale, Ilio; Criollo, Alfredo; Vicencio, José Miguel; Hickman, John A; Geneste, Olivier; Kroemer, Guido

    2007-09-15

    When added to cells, a variety of autophagy inducers that operate through distinct mechanisms and target different organelles for autophagic destruction (mitochondria in mitophagy, endoplasmic reticulum in reticulophagy) rarely induce autophagic vacuolization in more than 50% or the cells. Here we show that this heterogeneity may be explained by cell cycle-specific effects. The BH3 mimetic ABT737, lithium, rapamycin, tunicamycin or nutrient depletion stereotypically induce autophagy preferentially in the G(1) and S phases of the cell cycle, as determined by simultaneous monitoring of cell cycle markers and the cytoplasmic aggregation of GFP-LC3 in autophagic vacuoles. These results point to a hitherto neglected crosstalk between autophagic vacuolization and cell cycle regulation.

  4. Gene expression profiling: cell cycle deregulation and aneuploidy do not cause breast cancer formation in WAP-SVT/t transgenic animals.

    Science.gov (United States)

    Klein, Andreas; Guhl, Eva; Zollinger, Raphael; Tzeng, Yin-Jeh; Wessel, Ralf; Hummel, Michael; Graessmann, Monika; Graessmann, Adolf

    2005-05-01

    Microarray studies revealed that as a first hit the SV40 T/t antigen causes deregulation of 462 genes in mammary gland cells (ME cells) of WAP-SVT/t transgenic animals. The majority of deregulated genes are cell proliferation specific and Rb-E2F dependent, causing ME cell proliferation and gland hyperplasia but not breast cancer formation. In the breast tumor cells a further 207 genes are differentially expressed, most of them belonging to the cell communication category. In tissue culture breast tumor cells frequently switch off WAP-SVT/t transgene expression and regain the morphology and growth characteristics of normal ME cells, although the tumor-revertant cells are aneuploid and only 114 genes regain the expression level of normal ME cells. The profile of retransformants shows that only 38 deregulated genes are tumor-specific, and that none of them is considered to be a typical breast cancer gene.

  5. Chromatin association of UHRF1 during the cell cycle

    KAUST Repository

    Al-Gashgari, Bothayna

    2017-05-01

    Ubiquitin-like with PHD and RING Finger domains 1 (UHRF1) is a nuclear protein that associates with chromatin. Regardless of the various functions of UHRF1 in the cell, one of its more important functions is its role in the maintenance of DNA methylation patterns by the recruitment of DNMT1. Studies on UHRF1 based on this function have revealed the importance of UHRF1 during the cell cycle. Moreover, based on different studies various factors were described to be involved in the regulation of UHRF1 with different functionalities that can control its binding affinity to different targets on chromatin. These factors are regulated differently in a cell cycle specific manner. In light of this, we propose that UHRF1 has different binding behaviors during the cell cycle in regard to its association with chromatin. In this project, we first analyzed the binding behavior of endogenous UHRF1 from different unsynchronized cell systems in pull-down assays with peptides and oligonucleotides. Moreover, to analyze UHRF1 binding behavior during the cell cycle, we used two different approaches. First we sorted Jurkat and HT1080 cells based on their cell cycle stage using FACS analysis. Additionally, we synchronized HeLa cells to different stages of the cell cycle by chemical treatments, and used extracts from cellsorting and cell synchronization experiments for pull-down assays. We observed that UHRF1 in different cell systems has different preferences in regard to its binding to H3 unmodified and H3K9me3. Moreover, we detected that UHRF1, in general, displays different patterns between different stages of cell cycle; however, we cannot draw a final model for UHRF1 binding pattern during cell cycle.

  6. Effect of proton and gamma irradiation on human lung carcinoma cells: Gene expression, cell cycle, cell death, epithelial–mesenchymal transition and cancer-stem cell trait as biological end points

    Energy Technology Data Exchange (ETDEWEB)

    Narang, Himanshi, E-mail: narangh@barc.gov.in [Radiation Biology and Health Sciences Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Kumar, Amit [Radiation Biology and Health Sciences Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Bhat, Nagesh [Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Pandey, Badri N.; Ghosh, Anu [Radiation Biology and Health Sciences Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2015-10-15

    Highlights: • Biological effectiveness of proton and gamma irradiation is compared in A549 cells. • Proton irradiation is two times more cytotoxic than gamma irradiation. • It alters ten times more number of early genes, as observed by microarray study. • It does not enhance cell migration, invasion and adhesion, unlike gamma irradiation. • It was more effective in reducing the percentage of cancer stem cell like cells. - Abstract: Proton beam therapy is a cutting edge modality over conventional gamma radiotherapy because of its physical dose deposition advantage. However, not much is known about its biological effects vis-a-vis gamma irradiation. Here we investigated the effect of proton- and gamma- irradiation on cell cycle, death, epithelial-mesenchymal transition (EMT) and “stemness” in human non-small cell lung carcinoma cells (A549). Proton beam (3 MeV) was two times more cytotoxic than gamma radiation and induced higher and longer cell cycle arrest. At equivalent doses, numbers of genes responsive to proton irradiation were ten times higher than those responsive to gamma irradiation. At equitoxic doses, the proton-irradiated cells had reduced cell adhesion and migration ability as compared to the gamma-irradiated cells. It was also more effective in reducing population of Cancer Stem Cell (CSC) like cells as revealed by aldehyde dehydrogenase activity and surface phenotyping by CD44{sup +}, a CSC marker. These results can have significant implications for proton therapy in the context of suppression of molecular and cellular processes that are fundamental to tumor expansion.

  7. Microarray Analysis on Gene Regulation by Estrogen, Progesterone and Tamoxifen in Human Endometrial Stromal Cells

    Directory of Open Access Journals (Sweden)

    Chun-E Ren

    2015-03-01

    Full Text Available Epithelial stromal cells represent a major cellular component of human uterine endometrium that is subject to tight hormonal regulation. Through cell-cell contacts and/or paracrine mechanisms, stromal cells play a significant role in the malignant transformation of epithelial cells. We isolated stromal cells from normal human endometrium and investigated the morphological and transcriptional changes induced by estrogen, progesterone and tamoxifen. We demonstrated that stromal cells express appreciable levels of estrogen and progesterone receptors and undergo different morphological changes upon hormonal stimulation. Microarray analysis indicated that both estrogen and progesterone induced dramatic alterations in a variety of genes associated with cell structure, transcription, cell cycle, and signaling. However, divergent patterns of changes, and in some genes opposite effects, were observed for the two hormones. A large number of genes are identified as novel targets for hormonal regulation. These hormone-responsive genes may be involved in normal uterine function and the development of endometrial malignancies.

  8. The tumor suppressor SirT2 regulates cell cycle progression and genome stability by modulating the mitotic deposition of H4K20 methylation

    Science.gov (United States)

    The establishment of the epigenetic mark H4K20me1 (monomethylation of H4K20) by PR-Set7 during G2/M directly impacts S-phase progression and genome stability. However, the mechanisms involved in the regulation of this event are not well understood. Here we show that SirT2 regulates H4K20me1 depositi...

  9. Intermediate filaments and gene regulation.

    Science.gov (United States)

    Traub, P

    1995-01-01

    The biological role of intermediate filaments (IFs) of eukaryotic cells is still a matter of conjecture. On the basis of immunofluorescence and electron microscopic observations, they appear to play a cytoskeletal role in that they stabilize cellular structure and organize the distribution and interactions of intracellular organelles and components. The expression of a large number of cell type-specific and developmentally regulated subunit proteins is believed to provide multicellular organisms with different IF systems capable of differential interactions with the various substructures and components of their multiple, differentiated cells. However, the destruction of distinct IF systems by manipulation of cultured cells or by knock-out mutation of IF subunit proteins in transgenic mice exerts relatively little influence on cellular morphology and physiology and on development of mutant animals. In order to rationalize this dilemma, the cytoskeletal concept of IF function has been extended to purport that cytoplasmic (c) IFs and their subunit proteins also play fundamental roles in gene regulation. It is based on the in vitro capacity of cIF(protein)s to interact with guanine-rich, single-stranded DNA, supercoiled DNA and histones, as well as on their close structural relatedness to gene-regulatory DNA-binding and nuclear matrix proteins. Since cIF proteins do not possess classical nuclear localization signals, it is proposed that cIFs directly penetrate the double nuclear membrane, exploiting the amphiphilic, membrane-active character of their subunit proteins. Since they can establish metastable multisite contacts with nuclear matrix structures and/or chromatin areas containing highly repetitive DNA sequence elements at the nuclear periphery, they are supposed to participate in chromosome distribution and chromatin organization in interphase nuclei of differentiated cells. Owing to their different DNA-binding specificities, the various cIF systems may in this

  10. Gene regulation is governed by a core network in hepatocellular carcinoma.

    Science.gov (United States)

    Gu, Zuguang; Zhang, Chenyu; Wang, Jin

    2012-05-01

    Hepatocellular carcinoma (HCC) is one of the most lethal cancers worldwide, and the mechanisms that lead to the disease are still relatively unclear. However, with the development of high-throughput technologies it is possible to gain a systematic view of biological systems to enhance the understanding of the roles of genes associated with HCC. Thus, analysis of the mechanism of molecule interactions in the context of gene regulatory networks can reveal specific sub-networks that lead to the development of HCC. In this study, we aimed to identify the most important gene regulations that are dysfunctional in HCC generation. Our method for constructing gene regulatory network is based on predicted target interactions, experimentally-supported interactions, and co-expression model. Regulators in the network included both transcription factors and microRNAs to provide a complete view of gene regulation. Analysis of gene regulatory network revealed that gene regulation in HCC is highly modular, in which different sets of regulators take charge of specific biological processes. We found that microRNAs mainly control biological functions related to mitochondria and oxidative reduction, while transcription factors control immune responses, extracellular activity and the cell cycle. On the higher level of gene regulation, there exists a core network that organizes regulations between different modules and maintains the robustness of the whole network. There is direct experimental evidence for most of the regulators in the core gene regulatory network relating to HCC. We infer it is the central controller of gene regulation. Finally, we explored the influence of the core gene regulatory network on biological pathways. Our analysis provides insights into the mechanism of transcriptional and post-transcriptional control in HCC. In particular, we highlight the importance of the core gene regulatory network; we propose that it is highly related to HCC and we believe further

  11. Effects of Camphorquinone on Cytotoxicity, Cell Cycle Regulation and Prostaglandin E2 Production of Dental Pulp Cells: Role of ROS, ATM/Chk2, MEK/ERK and Hemeoxygenase-1.

    Directory of Open Access Journals (Sweden)

    Mei-Chi Chang

    Full Text Available Camphorquinone (CQ is a popularly-used photosensitizer in composite resin restoration. In this study, the effects of CQ on cytotoxicity and inflammation-related genes and proteins expression of pulp cells were investigated. The role of reactive oxygen species (ROS, ATM/Chk2/p53 and hemeoxygenase-1 (HO-1 and MEK/ERK signaling was also evaluated. We found that ROS and free radicals may play important role in CQ toxicity. CQ (1 and 2 mM decreased the viability of pulp cells to about 70% and 50% of control, respectively. CQ also induced G2/M cell cycle arrest and apoptosis of pulp cells. The expression of type I collagen, cdc2, cyclin B, and cdc25C was inhibited, while p21, HO-1 and cyclooxygenase-2 (COX-2 were stimulated by CQ. CQ also activated ATM, Chk2, and p53 phosphorylation and GADD45α expression. Besides, exposure to CQ increased cellular ROS level and 8-isoprostane production. CQ also stimulated COX-2 expression and PGE2 production of pulp cells. The reduction of cell viability caused by CQ can be attenuated by N-acetyl-L-cysteine (NAC, catalase and superoxide dismutase (SOD, but can be promoted by Zinc protoporphyin (ZnPP. CQ stimulated ERK1/2 phosphorylation, and U0126 prevented the CQ-induced COX-2 expression and prostaglandin E2 (PGE2 production. These results indicate that CQ may cause cytotoxicity, cell cycle arrest, apoptosis, and PGE2 production of pulp cells. These events could be due to stimulation of ROS and 8-isoprostane production, ATM/Chk2/p53 signaling, HO-1, COX-2 and p21 expression, as well as the inhibition of cdc2, cdc25C and cyclin B1. These results are important for understanding the role of ROS in pathogenesis of pulp necrosis and pulpal inflammation after clinical composite resin filling.

  12. S-phase Synchronization Facilitates the Early Progression of Induced-Cardiomyocyte Reprogramming through Enhanced Cell-Cycle Exit.

    Science.gov (United States)

    Bektik, Emre; Dennis, Adrienne; Pawlowski, Gary; Zhou, Chen; Maleski, Danielle; Takahashi, Satoru; Laurita, Kenneth R; Deschênes, Isabelle; Fu, Ji-Dong

    2018-05-04

    Direct reprogramming of fibroblasts into induced cardiomyocytes (iCMs) holds a great promise for regenerative medicine and has been studied in several major directions. However, cell-cycle regulation, a fundamental biological process, has not been investigated during iCM-reprogramming. Here, our time-lapse imaging on iCMs, reprogrammed by Gata4, Mef2c, and Tbx5 (GMT) monocistronic retroviruses, revealed that iCM-reprogramming was majorly initiated at late-G1- or S-phase and nearly half of GMT-reprogrammed iCMs divided soon after reprogramming. iCMs exited cell cycle along the process of reprogramming with decreased percentage of 5-ethynyl-20-deoxyuridine (EdU)⁺/α-myosin heavy chain (αMHC)-GFP⁺ cells. S-phase synchronization post-GMT-infection could enhance cell-cycle exit of reprogrammed iCMs and yield more GFP high iCMs, which achieved an advanced reprogramming with more expression of cardiac genes than GFP low cells. However, S-phase synchronization did not enhance the reprogramming with a polycistronic-viral vector, in which cell-cycle exit had been accelerated. In conclusion, post-infection synchronization of S-phase facilitated the early progression of GMT-reprogramming through a mechanism of enhanced cell-cycle exit.

  13. Centrosome/Cell cycle uncoupling and elimination in the endoreduplicating intestinal cells of C. elegans.

    Directory of Open Access Journals (Sweden)

    Yu Lu

    Full Text Available The centrosome cycle is most often coordinated with mitotic cell division through the activity of various essential cell cycle regulators, consequently ensuring that the centriole is duplicated once, and only once, per cell cycle. However, this coupling can be altered in specific developmental contexts; for example, multi-ciliated cells generate hundreds of centrioles without any S-phase requirement for their biogenesis, while Drosophila follicle cells eliminate their centrosomes as they begin to endoreduplicate. In order to better understand how the centrosome cycle and the cell cycle are coordinated in a developmental context we use the endoreduplicating intestinal cell lineage of C. elegans to address how novel variations of the cell cycle impact this important process. In C. elegans, the larval intestinal cells undergo one nuclear division without subsequent cytokinesis, followed by four endocycles that are characterized by successive rounds of S-phase. We monitored the levels of centriolar/centrosomal markers and found that centrosomes lose their pericentriolar material following the nuclear division that occurs during the L1 stage and is thereafter never re-gained. The centrioles then become refractory to S phase regulators that would normally promote duplication during the first endocycle, after which they are eliminated during the L2 stage. Furthermore, we show that SPD-2 plays a central role in the numeral regulation of centrioles as a potential target of CDK activity. On the other hand, the phosphorylation on SPD-2 by Polo-like kinase, the transcriptional regulation of genes that affect centriole biogenesis, and the ubiquitin/proteasome degradation pathway, contribute collectively to the final elimination of the centrioles during the L2 stage.

  14. DNA fragmentation and cell cycle arrest: a hallmark of apoptosis induced by Ruta graveolens in human colon cancer cells.

    Science.gov (United States)

    Arora, Shagun; Tandon, Simran

    2015-01-01

    In the present study, we investigated the anti-cancer effect of various potencies of Ruta graveolens (Ruta) on COLO-205 cell line, as evidenced by cytotoxicity, migration, clonogenecity, morphological and biochemical changes and modification in the levels of genes associated with apoptosis and cell cycle. On treatment of COLO-205 cells maximal effects were seen with mother tincture (MT) and 30C potencies, wherein decrease in cell viability along with reduced clonogenecity and migration capabilities were noted. In addition morphological and biochemical alterations such as nuclear changes (fragmented nuclei with condensed chromatin) and DNA ladder-like pattern (increased amount of fragmented DNA) in COLO-205 cells indicating apoptotic related cell death were seen. The expression of apoptosis and cell-cycle related regulatory genes assessed by reverse transcriptase-PCR revealed an up-regulation of caspase 9, caspase-3, Bax, p21 and p27 expression and down-regulation of Bcl-2 expression in treated cells. The mode of cell death was suggestive of intrinsic apoptotic pathway along with cell cycle arrest at the G2/M of the cell cycle. Our findings indicate that phytochemicals present in Ruta showed potential for natural therapeutic product development for colon carcinoma. Copyright © 2014 The Faculty of Homeopathy. Published by Elsevier Ltd. All rights reserved.

  15. Cell cycle synchronization and BrdU incorporation as a tool to study the possible selective elimination of ErbB1 gene in the micronuclei in A549 cells

    International Nuclear Information System (INIS)

    Lauand, C.; Niero, E.L.; Dias, V.M.; Machado-Santelli, G.M.

    2015-01-01

    Lung cancer often exhibits molecular changes, such as the overexpression of the ErbB1 gene that encodes epidermal growth factor receptor (EGFR). ErbB1 amplification and mutation are associated with tumor aggressiveness and low response to therapy. The aim of the present study was to design a schedule to synchronize the cell cycle of A549 cell line (a non-small cell lung cancer) and to analyze the possible association between the micronuclei (MNs) and the extrusion of ErbB1 gene extra-copies. After double blocking, by the process of fetal bovine serum deprivation and vincristine treatment, MNs formation was monitored with 5-bromo-2-deoxyuridine (BrdU) incorporation, which is an S-phase marker. Statistical analyses allowed us to infer that MNs may arise both in mitosis as well as in interphase. The MNs were able to replicate their DNA and this process seemed to be non-synchronous with the main cell nuclei. The presence of ErbB1 gene in the MNs was evaluated by fluorescent in situ hybridization (FISH). ErbB1 sequences were detected in the MNs, but a relation between the MNs formation and extrusion of amplified ErbB1could not be established. The present study sought to elucidate the meaning of MNs formation and its association with the elimination of oncogenes or other amplified sequences from the tumor cells

  16. Cell cycle synchronization and BrdU incorporation as a tool to study the possible selective elimination of ErbB1 gene in the micronuclei in A549 cells

    Energy Technology Data Exchange (ETDEWEB)

    Lauand, C.; Niero, E.L.; Dias, V.M.; Machado-Santelli, G.M. [Departamento de Biologia Celular e do Desenvolvimento, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP (Brazil)

    2015-03-06

    Lung cancer often exhibits molecular changes, such as the overexpression of the ErbB1 gene that encodes epidermal growth factor receptor (EGFR). ErbB1 amplification and mutation are associated with tumor aggressiveness and low response to therapy. The aim of the present study was to design a schedule to synchronize the cell cycle of A549 cell line (a non-small cell lung cancer) and to analyze the possible association between the micronuclei (MNs) and the extrusion of ErbB1 gene extra-copies. After double blocking, by the process of fetal bovine serum deprivation and vincristine treatment, MNs formation was monitored with 5-bromo-2-deoxyuridine (BrdU) incorporation, which is an S-phase marker. Statistical analyses allowed us to infer that MNs may arise both in mitosis as well as in interphase. The MNs were able to replicate their DNA and this process seemed to be non-synchronous with the main cell nuclei. The presence of ErbB1 gene in the MNs was evaluated by fluorescent in situ hybridization (FISH). ErbB1 sequences were detected in the MNs, but a relation between the MNs formation and extrusion of amplified ErbB1could not be established. The present study sought to elucidate the meaning of MNs formation and its association with the elimination of oncogenes or other amplified sequences from the tumor cells.

  17. Control of density-dependent, cell state-specific signal transduction by the cell adhesion molecule CEACAM1, and its influence on cell cycle regulation

    International Nuclear Information System (INIS)

    Scheffrahn, Inka; Singer, Bernhard B.; Sigmundsson, Kristmundur; Lucka, Lothar; Oebrink, Bjoern

    2005-01-01

    Growth factor receptors, extracellular matrix receptors, and cell-cell adhesion molecules co-operate in regulating the activities of intracellular signaling pathways. Here, we demonstrate that the cell adhesion molecule CEACAM1 co-regulates growth-factor-induced DNA synthesis in NBT-II epithelial cells in a cell-density-dependent manner. CEACAM1 exerted its effects by regulating the activity of the Erk 1/2 MAP kinase pathway and the expression levels of the cyclin-dependent kinase inhibitor p27 Kip1 . Interestingly, both inhibitory and stimulatory effects were observed. Confluent cells continuously exposed to fetal calf serum showed little Erk activity and DNA synthesis compared with sparse cells. Under these conditions, anti-CEACAM1 antibodies strongly stimulated Erk activation, decreased p27 expression, and induced DNA synthesis. In serum-starved confluent cells, re-addition of 10% fetal calf serum activated the Erk pathway, decreased p27 expression, and stimulated DNA synthesis to the same levels as in sparse cells. Under these conditions anti-CEACAM1 antibodies de-activated Erk, restored the level of p27, and inhibited DNA synthesis. These data indicate that CEACAM1 mediates contact inhibition of proliferation in cells that are constantly exposed to growth factors, but co-activates growth-factor-induced proliferation in cells that have been starved for growth factors; exposure to extracellular CEACAM1 ligands reverts these responses

  18. Genomic analysis reveals a potential role for cell cycle perturbation in HCV-mediated apoptosis of cultured hepatocytes.

    Directory of Open Access Journals (Sweden)

    Kathie-Anne Walters

    2009-01-01

    Full Text Available The mechanisms of liver injury associated with chronic HCV infection, as well as the individual roles of both viral and host factors, are not clearly defined. However, it is becoming increasingly clear that direct cytopathic effects, in addition to immune-mediated processes, play an important role in liver injury. Gene expression profiling during multiple time-points of acute HCV infection of cultured Huh-7.5 cells was performed to gain insight into the cellular mechanism of HCV-associated cytopathic effect. Maximal induction of cell-death-related genes and appearance of activated caspase-3 in HCV-infected cells coincided with peak viral replication, suggesting a link between viral load and apoptosis. Gene ontology analysis revealed that many of the cell-death genes function to induce apoptosis in response to cell cycle arrest. Labeling of dividing cells in culture followed by flow cytometry also demonstrated the presence of significantly fewer cells in S-phase in HCV-infected relative to mock cultures, suggesting HCV infection is associated with delayed cell cycle progression. Regulation of numerous genes involved in anti-oxidative stress response and TGF-beta1 signaling suggest these as possible causes of delayed cell cycle progression. Significantly, a subset of cell-death genes regulated during in vitro HCV infection was similarly regulated specifically in liver tissue from a cohort of HCV-infected liver transplant patients with rapidly progressive fibrosis. Collectively, these data suggest that HCV mediates direct cytopathic effects through deregulation of the cell cycle and that this process may contribute to liver disease progression. This in vitro system could be utilized to further define the cellular mechanism of this perturbation.

  19. The KDM5 family is required for activation of pro-proliferative cell cycle genes during adipocyte differentiation

    DEFF Research Database (Denmark)

    Brier, Ann-Sofie B; Loft, Anne; Madsen, Jesper G S

    2017-01-01

    The KDM5 family of histone demethylases removes the H3K4 tri-methylation (H3K4me3) mark frequently found at promoter regions of actively transcribed genes and is therefore generally considered to contribute to corepression. In this study, we show that knockdown (KD) of all expressed members of th...

  20. Molecular Cogs: Interplay between Circadian Clock and Cell Cycle.

    Science.gov (United States)

    Gaucher, Jonathan; Montellier, Emilie; Sassone-Corsi, Paolo

    2018-05-01

    The cell cycle and the circadian clock operate as biological oscillators whose timed functions are tightly regulated. Accumulating evidence illustrates the presence of molecular links between these two oscillators. This mutual interplay utilizes various coupling mechanisms, such as the use of common regulators. The connection between these two cyclic systems has unique interest in the context of aberrant cell proliferation since both of these oscillators are frequently misregulated in cancer cells. Further studies will provide deeper understanding of the detailed molecular connections between the cell cycle and the circadian clock and may also serve as a basis for the design of innovative therapeutic strategies. Copyright © 2018 Elsevier Ltd. All rights reserved.

  1. Interactome maps of mouse gene regulatory domains reveal basic principles of transcriptional regulation

    DEFF Research Database (Denmark)

    Kieffer-Kwon, Kyong-Rim; Tang, Zhonghui; Mathe, Ewy

    2013-01-01

    IA-PET technologies to map the promoter-enhancer interactomes of pluripotent ES cells and differentiated B lymphocytes. We confirm that enhancer usage varies widely across tissues. Unexpectedly, we find that this feature extends to broadly transcribed genes, including Myc and Pim1 cell-cycle regulators, which...... associate with an entirely different set of enhancers in ES and B cells. By means of high-resolution CpG methylomes, genome editing, and digital footprinting, we show that these enhancers recruit lineage-determining factors. Furthermore, we demonstrate that the turning on and off of enhancers during...

  2. Cell cycle G2/M arrest through an S phase-dependent mechanism by HIV-1 viral protein R.

    Science.gov (United States)

    Li, Ge; Park, Hyeon U; Liang, Dong; Zhao, Richard Y

    2010-07-07

    Cell cycle G2 arrest induced by HIV-1 Vpr is thought to benefit viral proliferation by providing an optimized cellular environment for viral replication and by skipping host immune responses. Even though Vpr-induced G2 arrest has been studied extensively, how Vpr triggers G2 arrest remains elusive. To examine this initiation event, we measured the Vpr effect over a single cell cycle. We found that even though Vpr stops the cell cycle at the G2/M phase, but the initiation event actually occurs in the S phase of the cell cycle. Specifically, Vpr triggers activation of Chk1 through Ser345 phosphorylation in an S phase-dependent manner. The S phase-dependent requirement of Chk1-Ser345 phosphorylation by Vpr was confirmed by siRNA gene silencing and site-directed mutagenesis. Moreover, downregulation of DNA replication licensing factors Cdt1 by siRNA significantly reduced Vpr-induced Chk1-Ser345 phosphorylation and G2 arrest. Even though hydroxyurea (HU) and ultraviolet light (UV) also induce Chk1-Ser345 phosphorylation in S phase under the same conditions, neither HU nor UV-treated cells were able to pass through S phase, whereas vpr-expressing cells completed S phase and stopped at the G2/M boundary. Furthermore, unlike HU/UV, Vpr promotes Chk1- and proteasome-mediated protein degradations of Cdc25B/C for G2 induction; in contrast, Vpr had little or no effect on Cdc25A protein degradation normally mediated by HU/UV. These data suggest that Vpr induces cell cycle G2 arrest through a unique molecular mechanism that regulates host cell cycle regulation in an S-phase dependent fashion.

  3. Cell cycle G2/M arrest through an S phase-dependent mechanism by HIV-1 viral protein R

    Directory of Open Access Journals (Sweden)

    Liang Dong

    2010-07-01

    Full Text Available Abstract Background Cell cycle G2 arrest induced by HIV-1 Vpr is thought to benefit viral proliferation by providing an optimized cellular environment for viral replication and by skipping host immune responses. Even though Vpr-induced G2 arrest has been studied extensively, how Vpr triggers G2 arrest remains elusive. Results To examine this initiation event, we measured the Vpr effect over a single cell cycle. We found that even though Vpr stops the cell cycle at the G2/M phase, but the initiation event actually occurs in the S phase of the cell cycle. Specifically, Vpr triggers activation of Chk1 through Ser345 phosphorylation in an S phase-dependent manner. The S phase-dependent requirement of Chk1-Ser345 phosphorylation by Vpr was confirmed by siRNA gene silencing and site-directed mutagenesis. Moreover, downregulation of DNA replication licensing factors Cdt1 by siRNA significantly reduced Vpr-induced Chk1-Ser345 phosphorylation and G2 arrest. Even though hydroxyurea (HU and ultraviolet light (UV also induce Chk1-Ser345 phosphorylation in S phase under the same conditions, neither HU nor UV-treated cells were able to pass through S phase, whereas vpr-expressing cells completed S phase and stopped at the G2/M boundary. Furthermore, unlike HU/UV, Vpr promotes Chk1- and proteasome-mediated protein degradations of Cdc25B/C for G2 induction; in contrast, Vpr had little or no effect on Cdc25A protein degradation normally mediated by HU/UV. Conclusions These data suggest that Vpr induces cell cycle G2 arrest through a unique molecular mechanism that regulates host cell cycle regulation in an S-phase dependent fashion.

  4. Deletion of the topoisomerase III gene in the hyperthermophilic archaeon Sulfolobus islandicus results in slow growth and defects in cell cycle control

    DEFF Research Database (Denmark)

    Li, Xiyang; Guo, Li; Deng, Ling

    2011-01-01

    Topoisomerase III (topo III), a type IA topoisomerase, is widespread in hyperthermophilic archaea. In order to interrogate the in vivo role of archaeal topo III, we constructed and characterized a topo III gene deletion mutant of Sulfolobus islandicus. The mutant was viable but grew more slowly...... results suggest that the enzyme may serve roles in chromosomal segregation and control of the level of supercoiling in the cell....

  5. Conditional inactivation of PDCD2 induces p53 activation and cell cycle arrest

    Directory of Open Access Journals (Sweden)

    Celine J. Granier

    2014-08-01

    Full Text Available PDCD2 (programmed cell death domain 2 is a highly conserved, zinc finger MYND domain-containing protein essential for normal development in the fly, zebrafish and mouse. The molecular functions and cellular activities of PDCD2 remain unclear. In order to better understand the functions of PDCD2 in mammalian development, we have examined PDCD2 activity in mouse blastocyst embryos, as well as in mouse embryonic stem cells (ESCs and embryonic fibroblasts (MEFs. We have studied mice bearing a targeted PDCD2 locus functioning as a null allele through a splicing gene trap, or as a conditional knockout, by deletion of exon2 containing the MYND domain. Tamoxifen-induced knockout of PDCD2 in MEFs, as well as in ESCs, leads to defects in progression from the G1 to the S phase of cell cycle, associated with increased levels of p53 protein and p53 target genes. G1 prolongation in ESCs was not associated with induction of differentiation. Loss of entry into S phase of the cell cycle and marked induction of nuclear p53 were also observed in PDCD2 knockout blastocysts. These results demonstrate a unique role for PDCD2 in regulating the cell cycle and p53 activation during early embryonic development of the mouse.

  6. A nuclear glutathione cycle within the cell cycle.

    Science.gov (United States)

    Diaz Vivancos, Pedro; Wolff, Tonja; Markovic, Jelena; Pallardó, Federico V; Foyer, Christine H

    2010-10-15

    The complex antioxidant network of plant and animal cells has the thiol tripeptide GSH at its centre to buffer ROS (reactive oxygen species) and facilitate cellular redox signalling which controls growth, development and defence. GSH is found in nearly every compartment of the cell, including the nucleus. Transport between the different intracellular compartments is pivotal to the regulation of cell proliferation. GSH co-localizes with nuclear DNA at the early stages of proliferation in plant and animal cells. Moreover, GSH recruitment and sequestration in the nucleus during the G1- and S-phases of the cell cycle has a profound impact on cellular redox homoeostasis and on gene expression. For example, the abundance of transcripts encoding stress and defence proteins is decreased when GSH is sequestered in the nucleus. The functions of GSHn (nuclear GSH) are considered in the present review in the context of whole-cell redox homoeostasis and signalling, as well as potential mechanisms for GSH transport into the nucleus. We also discuss the possible role of GSHn as a regulator of nuclear proteins such as histones and PARP [poly(ADP-ribose) polymerase] that control genetic and epigenetic events. In this way, a high level of GSH in the nucleus may not only have an immediate effect on gene expression patterns, but also contribute to how cells retain a memory of the cellular redox environment that is transferred through generations.

  7. Cell cycle sibling rivalry: Cdc2 vs. Cdk2.

    Science.gov (United States)

    Kaldis, Philipp; Aleem, Eiman

    2005-11-01

    It has been long believed that the cyclin-dependent kinase 2 (Cdk2) binds to cyclin E or cyclin A and exclusively promotes the G1/S phase transition and that Cdc2/cyclin B complexes play a major role in mitosis. We now provide evidence that Cdc2 binds to cyclin E (in addition to cyclin A and B) and is able to promote the G1/S transition. This new concept indicates that both Cdk2 and/or Cdc2 can drive cells through G1/S phase in parallel. In this review we discuss the classic cell cycle model and how results from knockout mice provide new evidence that refute this model. We focus on the roles of Cdc2 and p27 in regulating the mammalian cell cycle and propose a new model for cell cycle regulation that accommodates these novel findings.

  8. A complex regulatory network coordinating cell cycles during C. elegans development is revealed by a genome-wide RNAi screen.

    Science.gov (United States)

    Roy, Sarah H; Tobin, David V; Memar, Nadin; Beltz, Eleanor; Holmen, Jenna; Clayton, Joseph E; Chiu, Daniel J; Young, Laura D; Green, Travis H; Lubin, Isabella; Liu, Yuying; Conradt, Barbara; Saito, R Mako

    2014-02-28

    The development and homeostasis of multicellular animals requires precise coordination of cell division and differentiation. We performed a genome-wide RNA interference screen in Caenorhabditis elegans to reveal the components of a regulatory network that promotes developmentally programmed cell-cycle quiescence. The 107 identified genes are predicted to constitute regulatory networks that are conserved among higher animals because almost half of the genes are represented by clear human orthologs. Using a series of mutant backgrounds to assess their genetic activities, the RNA interference clones displaying similar properties were clustered to establish potential regulatory relationships within the network. This approach uncovered four distinct genetic pathways controlling cell-cycle entry during intestinal organogenesis. The enhanced phenotypes observed for animals carrying compound mutations attest to the collaboration between distinct mechanisms to ensure strict developmental regulation of cell cycles. Moreover, we characterized ubc-25, a gene encoding an E2 ubiquitin-conjugating enzyme whose human ortholog, UBE2Q2, is deregulated in several cancers. Our genetic analyses suggested that ubc-25 acts in a linear pathway with cul-1/Cul1, in parallel to pathways employing cki-1/p27 and lin-35/pRb to promote cell-cycle quiescence. Further investigation of the potential regulatory mechanism demonstrated that ubc-25 activity negatively regulates CYE-1/cyclin E protein abundance in vivo. Together, our results show that the ubc-25-mediated pathway acts within a complex network that integrates the actions of multiple molecular mechanisms to control cell cycles during development. Copyright © 2014 Roy et al.

  9. A cell cycle role for the epigenetic factor CTCF-L/BORIS.

    Directory of Open Access Journals (Sweden)

    Manuel Rosa-Garrido

    Full Text Available CTCF is a ubiquitous epigenetic regulator that has been proposed as a master keeper of chromatin organisation. CTCF-like, or BORIS, is thought to antagonise CTCF and has been found in normal testis, ovary and a large variety of tumour cells. The cellular function of BORIS remains intriguing although it might be involved in developmental reprogramming of gene expression patterns. We here unravel the expression of CTCF and BORIS proteins throughout human epidermis. While CTCF is widely distributed within the nucleus, BORIS is confined to the nucleolus and other euchromatin domains. Nascent RNA experiments in primary keratinocytes revealed that endogenous BORIS is present in active transcription sites. Interestingly, BORIS also localises to interphase centrosomes suggesting a role in the cell cycle. Blocking the cell cycle at S phase or mitosis, or causing DNA damage, produced a striking accumulation of BORIS. Consistently, ectopic expression of wild type or GFP- BORIS provoked a higher rate of S phase cells as well as genomic instability by mitosis failure. Furthermore, down-regulation of endogenous BORIS by specific shRNAs inhibited both RNA transcription and cell cycle progression. The results altogether suggest a role for BORIS in coordinating S phase events with mitosis.

  10. The Tlx gene regulates the timing of neurogenesis in the cortex.

    Science.gov (United States)

    Roy, Kristine; Kuznicki, Kathleen; Wu, Qiang; Sun, Zhuoxin; Bock, Dagmar; Schutz, Gunther; Vranich, Nancy; Monaghan, A Paula

    2004-09-22

    The tailless (tlx) gene is a forebrain-restricted transcription factor. Tlx mutant animals exhibit a reduction in the size of the cerebral hemispheres and associated structures (Monaghan et al., 1997). Superficial cortical layers are specifically reduced, whereas deep layers are relatively unaltered (Land and Monaghan, 2003). To determine whether the adult laminar phenotype has a developmental etiology and whether it is associated with a change in proliferation/differentiation decisions, we examined the cell cycle and neurogenesis in the embryonic cortex. We found that there is a temporal and regional requirement for the Tlx protein in progenitor cells (PCs). Neurons prematurely differentiate at all rostrocaudal levels up to mid-neurogenesis in mutant animals. Heterozygote animals have an intermediate phenotype indicating there is a threshold requirement for Tlx in early cortical neurogenesis. Our studies indicate that PCs in the ventricular zone are sensitive to loss of Tlx in caudal regions only; however, PCs in the subventricular zone are altered at all rostrocaudal levels in tlx-deficient animals. Furthermore, we found that the cell cycle is shorter from embryonic day 9.5 in tlx-/- embryos. At mid-neurogenesis, the PC population becomes depleted, and late PCs have a longer cell cycle in tlx-deficient animals. Consequently, later generated structures, such as upper cortical layers, the dentate gyrus, and the olfactory bulbs, are severely reduced. These studies indicate that tlx is an essential intrinsic regulator in the decision to proliferate or differentiate in the developing forebrain.

  11. Identification of let-7-regulated oncofetal genes

    DEFF Research Database (Denmark)

    Boyerinas, Benjamin; Park, Sun-Mi; Shomron, Noam

    2008-01-01

    -regulated at the end of embryonic development. Let-7 is often down-regulated early during cancer development, suggesting that let-7-regulated oncofetal genes (LOG) may become reexpressed in cancer cells. Using comparative bioinformatics, we have identified 12 conserved LOGs that include HMGA2 and IMP-1/CRD-BP. IMP-1...

  12. High-throughput gene expression profiling indicates dysregulation of intestinal cell cycle mediators and growth factors during primary simian immunodeficiency virus infection

    Energy Technology Data Exchange (ETDEWEB)

    George, Michael D; Sankaran, Sumathi; Reay, Elizabeth; Gelli, Angie C; Dandekar, Satya

    2003-07-20

    During primary simian immunodeficiency virus (SIV) infection, CD4+ T cells are severely depleted in gut-associated lymphoid tissue (GALT), while CD8+ T-cell numbers dramatically increase. To gain an understanding of the molecular basis of this disruption in T-cell homeostasis, host gene expression was monitored in longitudinal jejunum tissue biopsies from SIV-infected rhesus macaques by DNA microarray analysis. Transcription of cyclin E1, CDC2, retinoblastoma, transforming growth factor (TGF), fibroblast growth factor (FGF), and interleukin-2 was repressed while cyclins B1 and D2 and transcription factor E2F were upregulated, indicating a complex dysregulation of growth and proliferation within the intestinal mucosa. Innate, cell-mediated, and humoral immune responses were markedly upregulated in animals that significantly reduced their viral loads and retained more intestinal CD4+ T cells. We conclude that the alterations in intestinal gene expression during primary SIV infection were characteristic of a broad-range immune response, and reflective of the efficacy of viral suppression.

  13. High-throughput gene expression profiling indicates dysregulation of intestinal cell cycle mediators and growth factors during primary simian immunodeficiency virus infection

    International Nuclear Information System (INIS)

    George, Michael D.; Sankaran, Sumathi; Reay, Elizabeth; Gelli, Angie C.; Dandekar, Satya

    2003-01-01

    During primary simian immunodeficiency virus (SIV) infection, CD4+ T cells are severely depleted in gut-associated lymphoid tissue (GALT), while CD8+ T-cell numbers dramatically increase. To gain an understanding of the molecular basis of this disruption in T-cell homeostasis, host gene expression was monitored in longitudinal jejunum tissue biopsies from SIV-infected rhesus macaques by DNA microarray analysis. Transcription of cyclin E1, CDC2, retinoblastoma, transforming growth factor (TGF), fibroblast growth factor (FGF), and interleukin-2 was repressed while cyclins B1 and D2 and transcription factor E2F were upregulated, indicating a complex dysregulation of growth and proliferation within the intestinal mucosa. Innate, cell-mediated, and humoral immune responses were markedly upregulated in animals that significantly reduced their viral loads and retained more intestinal CD4+ T cells. We conclude that the alterations in intestinal gene expression during primary SIV infection were characteristic of a broad-range immune response, and reflective of the efficacy of viral suppression

  14. Identification of a novel intergenic miRNA located between the human DDC and COBL genes with a potential function in cell cycle arrest.

    Science.gov (United States)

    Hoballa, Mohamad Hussein; Soltani, Bahram M; Mowla, Seyed Javad; Sheikhpour, Mojgan; Kay, Maryam

    2018-07-01

    Frequent abnormalities in 7p12 locus in different tumors like lung cancer candidate this region for novel regulatory elements. MiRNAs as novel regulatory elements encoded within the human genome are potentially oncomiRs or miR suppressors. Here, we have used bioinformatics tools to search for the novel miRNAs embedded within human chromosome 7p12. A bona fide stem loop (named mirZa precursor) had the features of producing a real miRNA (named miRZa) which was detected through RT-qPCR following the overexpression of its precursor. Then, endogenous miRZa was detected in human cell lines and tissues and sequenced. Consistent to the bioinformatics prediction, RT-qPCR as well as dual luciferase assay indicated that SMAD3 and IGF1R genes were targeted by miRZa. MiRZa-3p and miRZa-5p were downregulated in lung tumor tissue samples detected by RT-qPCR, and mirZa precursor overexpression in SW480 cells resulted in increased sub-G1 cell population. Overall, here we introduced a novel miRNA which is capable of targeting SMAD3 and IGF1R regulatory genes and increases the cell population in sub-G1 stage.

  15. Regulation of signaling genes by TGFβ during entry into dauer diapause in C. elegans

    Directory of Open Access Journals (Sweden)

    Patterson Garth I

    2004-09-01

    Full Text Available Abstract Background When resources are scant, C. elegans larvae arrest as long-lived dauers under the control of insulin/IGF- and TGFβ-related signaling pathways. However, critical questions remain regarding the regulation of this developmental event. How do three dozen insulin-like proteins regulate one tyrosine kinase receptor to control complex events in dauer, metabolism and aging? How are signals from the TGFβ and insulin/IGF pathways integrated? What gene expression programs do these pathways regulate, and how do they control complex downstream events? Results We have identified genes that show different levels of expression in a comparison of wild-type L2 or L3 larvae (non-dauer to TGFβ mutants at similar developmental stages undergoing dauer formation. Many insulin/IGF pathway and other known dauer regulatory genes have changes in expression that suggest strong positive feedback by the TGFβ pathway. In addition, many insulin-like ligand and novel genes with similarity to the extracellular domain of insulin/IGF receptors have altered expression. We have identified a large group of regulated genes with putative binding sites for the FOXO transcription factor, DAF-16. Genes with DAF-16 sites upstream of the transcription start site tend to be upregulated, whereas genes with DAF-16 sites downstream of the coding region tend to be downregulated. Finally, we also see strong regulation of many novel hedgehog- and patched-related genes, hormone biosynthetic genes, cell cycle genes, and other regulatory genes. Conclusions The feedback regulation of insulin/IGF pathway and other dauer genes that we observe would be predicted to amplify signals from the TGFβ pathway; this amplification may serve to ensure a decisive choice between "dauer" and "non-dauer", even if environmental cues are ambiguous. Up and down regulation of insulin-like ligands and novel genes with similarity to the extracellular domain of insulin/IGF receptors suggests opposing

  16. Antisense long noncoding RNAs regulate var gene activation in the malaria parasite Plasmodium falciparum.

    Science.gov (United States)

    Amit-Avraham, Inbar; Pozner, Guy; Eshar, Shiri; Fastman, Yair; Kolevzon, Netanel; Yavin, Eylon; Dzikowski, Ron

    2015-03-03

    The virulence of Plasmodium falciparum, the causative agent of the deadliest form of human malaria, is attributed to its ability to evade human immunity through antigenic variation. These parasites alternate between expression of variable antigens, encoded by members of a multicopy gene family named var. Immune evasion through antigenic variation depends on tight regulation of var gene expression, ensuring that only a single var gene is expressed at a time while the rest of the family is maintained transcriptionally silent. Understanding how a single gene is chosen for activation is critical for understanding mutually exclusive expression but remains a mystery. Here, we show that antisense long noncoding RNAs (lncRNAs) initiating from var introns are associated with the single active var gene at the time in the cell cycle when the single var upstream promoter is active. We demonstrate that these antisense transcripts are incorporated into chromatin, and that expression of these antisense lncRNAs in trans triggers activation of a silent var gene in a sequence- and dose-dependent manner. On the other hand, interference with these lncRNAs using complement peptide nucleic acid molecules down-regulated the active var gene, erased the epigenetic memory, and induced expression switching. Altogether, our data provide evidence that these antisense lncRNAs play a key role in regulating var gene activation and mutually exclusive expression.

  17. Microsporidia infection impacts the host cell's cycle and reduces host cell apoptosis

    Science.gov (United States)

    Higes, Mariano; Sagastume, Soledad; Juarranz, Ángeles; Dias-Almeida, Joyce; Budge, Giles E.; Meana, Aránzazu; Boonham, Neil

    2017-01-01

    Intracellular parasites can alter the cellular machinery of host cells to create a safe haven for their survival. In this regard, microsporidia are obligate intracellular fungal parasites with extremely reduced genomes and hence, they are strongly dependent on their host for energy and resources. To date, there are few studies into host cell manipulation by microsporidia, most of which have focused on morphological aspects. The microsporidia Nosema apis and Nosema ceranae are worldwide parasites of honey bees, infecting their ventricular epithelial cells. In this work, quantitative gene expression and histology were studied to investigate how these two parasites manipulate their host’s cells at the molecular level. Both these microsporidia provoke infection-induced regulation of genes involved in apoptosis and the cell cycle. The up-regulation of buffy (which encodes a pro-survival protein) and BIRC5 (belonging to the Inhibitor Apoptosis protein family) was observed after infection, shedding light on the pathways that these pathogens use to inhibit host cell apoptosis. Curiously, different routes related to cell cycle were modified after infection by each microsporidia. In the case of N. apis, cyclin B1, dacapo and E2F2 were up-regulated, whereas only cyclin E was up-regulated by N. ceranae, in both cases promoting the G1/S phase transition. This is the first report describing molecular pathways related to parasite-host interactions that are probably intended to ensure the parasite’s survival within the cell. PMID:28152065

  18. Ethyl acetate extract of Chinese medicinal herb Sarcandra glabra induces growth inhibition on human leukemic HL-60 cells, associated with cell cycle arrest and up-regulation of pro-apoptotic Bax/Bcl-2 ratio.

    Science.gov (United States)

    Li, W Y; Chiu, Lawrence C M; Lam, W S; Wong, W Y; Chan, Y T; Ho, Y P; Wong, Elaine Y L; Wong, Y S; Ooi, Vincent E C

    2007-02-01

    Sarcandra glabra (Thunb.) Nakai, colloquially known as Caoshanhu, is a Chinese medicinal herb with reported anti-tumor, anti-inflammatory, anti-viral and non-specific immunoenhancing properties. Although the plant has been clinically used for treating a variety of diseases, its bioactive ingredients are largely unknown and its mode of action has never been investigated. In this study, the anti-tumor property of ethyl acetate (EA) extract of S. glabra was investigated by determining its in vitro growth-inhibitory effects on a panel of human cancer cell lines of different histotypes. Growth inhibition of the EA extract on the cancer cells seemed to be selective, and the leukemic HL-60 was found to be the most responsive after 48 h of treatment (IC50=58 microg/ml). Flow cytometric studies further illustrated that the extract might interfere with DNA replication and thus arrested the cell cycle at S phase in the leukemic cells, followed by DNA fragmentation and loss of phospholipid asymmetry in the plasma membrane after 72 h of treatment. Concurrently, the pro-apoptotic Bax/Bcl-2 ratio was also up-regulated by more than 178% of the control level. All these findings suggested that the extract had initiated apoptosis to kill the leukemic cells. Results from this pioneer study help to establish a scientific foundation for future research and development of the bioactive ingredients in EA extract of S. glabra as efficacious anti-cancer agents.

  19. Influence of vitamin D on cell cycle, apoptosis, and some apoptosis related molecules in systemic lupus erythematosus

    Directory of Open Access Journals (Sweden)

    Nafise Tabasi

    2015-11-01

    Full Text Available Objective(s:Genetic and environmental factors are involved in the pathogenesis of systemic lupus erythematosus (SLE. Autoreactive lymphocytes are cleared through apoptosis and any disturbance in the apoptosis or clearance of apoptotic cells may disturb tolerance and lead to autoimmunity. Vitamin D has anti-proliferative effects and controls cell cycle progression. In this study we investigated the effects of vitamin D on cell cycle and apoptosis induction in lupus patients. Materials and Methods:Isolated peripheral blood mononuclear cells (PBMCs from 25 SLE patients were cultured in the presence of 50 nM of 1,25(OH2D3; then one part of the cells were stained with FITC labeled Annexin V and PI and were analyzed for apoptosis determination. For gene expression assessment of FasL, Bcl-2 and Bax, RNA was extracted from one another part of the cells, cDNA was synthesized and gene expression analysis was performed using Real time PCR. An additional part of the cells were treated with PI and the cell cycle was analyzed using flowcytometer. Results: The mean number of early apoptotic cells in vitamin D treated cells decreased significantly (18.48±7.9% compared to untreated cells (22.02±9.4% (P=0.008. Cell cycle analysis showed a significant increase in G1 phase in vitamin D treated cells (67.33±5.2% compared to non treated ones (60.77±5.7% (P =0.02. Vitamin D up-regulated the expression levels of Bcl-2 by (18.87 fold increase, and down-regulated expression of Bax (23% and FasL (25%. Conclusion:Vitamin D has regulatory effects on cell cycle progression, apoptosis and apoptosis related molecules in lupus patients.

  20. Combinatorial gene regulation in Plasmodium falciparum.

    NARCIS (Netherlands)

    Noort, V. van; Huynen, M.A.

    2006-01-01

    The malaria parasite Plasmodium falciparum has a complicated life cycle with large variations in its gene expression pattern, but it contains relatively few specific transcriptional regulators. To elucidate this paradox, we identified regulatory sequences, using an approach that integrates the

  1. Influence of cell cycle on responses of MCF-7 cells to benzo[a]pyrene

    Directory of Open Access Journals (Sweden)

    Giddings Ian

    2011-06-01

    Full Text Available Abstract Background Benzo[a]pyrene (BaP is a widespread environmental genotoxic carcinogen that damages DNA by forming adducts. This damage along with activation of the aryl hydrocarbon receptor (AHR induces complex transcriptional responses in cells. To investigate whether human cells are more susceptible to BaP in a particular phase of the cell cycle, synchronised breast carcinoma MCF-7 cells were exposed to BaP. Cell cycle progression was analysed by flow cytometry, DNA adduct formation was assessed by 32P-postlabeling analysis, microarrays of 44K human genome-wide oligos and RT-PCR were used to detect gene expression (mRNA changes and Western blotting was performed to determine the expression of some proteins, including cytochrome P450 (CYP 1A1 and CYP1B1, which are involved in BaP metabolism. Results Following BaP exposure, cells evaded G1 arrest and accumulated in S-phase. Higher levels of DNA damage occurred in S- and G2/M- compared with G0/G1-enriched cultures. Genes that were found to have altered expression included those involved in xenobiotic metabolism, apoptosis, cell cycle regulation and DNA repair. Gene ontology and pathway analysis showed the involvement of various signalling pathways in response to BaP exposure, such as the Catenin/Wnt pathway in G1, the ERK pathway in G1 and S, the Nrf2 pathway in S and G2/M and the Akt pathway in G2/M. An important finding was that higher levels of DNA damage in S- and G2/M-enriched cultures correlated with higher levels of CYP1A1 and CYP1B1 mRNA and proteins. Moreover, exposure of synchronised MCF-7 cells to BaP-7,8-diol-9,10-epoxide (BPDE, the ultimate carcinogenic metabolite of BaP, did not result in significant changes in DNA adduct levels at different phases of the cell cycle. Conclusions This study characterised the complex gene response to BaP in MCF-7 cells and revealed a strong correlation between the varying efficiency of BaP metabolism and DNA damage in different phases of the cell

  2. MMSET deregulation affects cell cycle progression and adhesion regulons in t(4;14) myeloma plasma cells

    Science.gov (United States)

    Brito, Jose L.R.; Walker, Brian; Jenner, Matthew; Dickens, Nicholas J.; Brown, Nicola J.M.; Ross, Fiona M.; Avramidou, Athanasia; Irving, Julie A.E.; Gonzalez, David; Davies, Faith E.; Morgan, Gareth J.

    2009-01-01

    Background The recurrent immunoglobulin translocation, t(4;14)(p16;q32) occurs in 15% of multiple myeloma patients and is associated with poor prognosis, through an unknown mechanism. The t(4;14) up-regulates fibroblast growth factor receptor 3 (FGFR3) and multiple myeloma SET domain (MMSET) genes. The involvement of MMSET in the pathogenesis of t(4;14) multiple myeloma and the mechanism or genes deregulated by MMSET upregulation are still unclear. Design and Methods The expression of MMSET was analyzed using a novel antibody. The involvement of MMSET in t(4;14) myelomagenesis was assessed by small interfering RNA mediated knockdown combined with several biological assays. In addition, the differential gene expression of MMSET-induced knockdown was analyzed with expression microarrays. MMSET gene targets in primary patient material was analyzed by expression microarrays. Results We found that MMSET isoforms are expressed in multiple myeloma cell lines, being exclusively up-regulated in t(4;14)-positive cells. Suppression of MMSET expression affected cell proliferation by both decreasing cell viability and cell cycle progression of cells with the t(4;14) translocation. These findings were associated with reduced expression of genes involved in the regulation of cell cycle progression (e.g. CCND2, CCNG1, BRCA1, AURKA and CHEK1), apoptosis (CASP1, CASP4 and FOXO3A) and cell adhesion (ADAM9 and DSG2). Furthermore, we identified genes involved in the latter processes that were differentially expressed in t(4;14) multiple myeloma patient samples. Conclusions In conclusion, dysregulation of MMSET affects the expression of several genes involved in the regulation of cell cycle progression, cell adhesion and survival. PMID:19059936

  3. Epigenetic dynamics across the cell cycle

    DEFF Research Database (Denmark)

    Kheir, Tony Bou; Lund, Anders H.

    2010-01-01

    Progression of the mammalian cell cycle depends on correct timing and co-ordination of a series of events, which are managed by the cellular transcriptional machinery and epigenetic mechanisms governing genome accessibility. Epigenetic chromatin modifications are dynamic across the cell cycle...... a correct inheritance of epigenetic chromatin modifications to daughter cells. In this chapter, we summarize the current knowledge on the dynamics of epigenetic chromatin modifications during progression of the cell cycle....

  4. Identification of genes differentially regulated in rat alveolar bone wound healing by subtractive hybridization.

    Science.gov (United States)

    Ohira, T; Myokai, F; Shiomi, N; Yamashiro, K; Yamamoto, T; Murayama, Y; Arai, H; Nishimura, F; Takashiba, S

    2004-07-01

    Periodontal healing requires the participation of regulatory molecules, cells, and scaffold or matrix. Here, we hypothesized that a certain set of genes is expressed in alveolar bone wound healing. Reciprocal subtraction gave 400 clones from the injured alveolar bone of Wistar rats. Identification of 34 genes and analysis of their expression in injured tissue revealed several clusters of unique gene regulation patterns, including the up-regulation at 1 wk of cytochrome c oxidase regulating electron transfer and energy metabolism, presumably occurring at the site of inflammation; up-regulation at 2.5 wks of pro-alpha-2 type I collagen involving the formation of a connective tissue structure; and up-regulation at 1 and 2 wks and down-regulation at 2.5 and 4 wks of ubiquitin carboxyl-terminal hydrolase l3 involving cell cycle, DNA repair, and stress response. The differential expression of genes may be associated with the processes of inflammation, wound contraction, and formation of a connective tissue structure.

  5. Glucose-ABL1-TOR Signaling Modulates Cell Cycle Tuning to Control Terminal Appressorial Cell Differentiation.

    Science.gov (United States)

    Marroquin-Guzman, Margarita; Sun, Guangchao; Wilson, Richard A

    2017-01-01

    The conserved target of rapamycin (TOR) pathway integrates growth and development with available nutrients, but how cellular glucose controls TOR function and signaling is poorly understood. Here, we provide functional evidence from the devastating rice blast fungus Magnaporthe oryzae that glucose can mediate TOR activity via the product of a novel carbon-responsive gene, ABL1, in order to tune cell cycle progression during infection-related development. Under nutrient-free conditions, wild type (WT) M. oryzae strains form terminal plant-infecting cells (appressoria) at the tips of germ tubes emerging from three-celled spores (conidia). WT appressorial development is accompanied by one round of mitosis followed by autophagic cell death of the conidium. In contrast, Δabl1 mutant strains undergo multiple rounds of accelerated mitosis in elongated germ tubes, produce few appressoria, and are abolished for autophagy. Treating WT spores with glucose or 2-deoxyglucose phenocopied Δabl1. Inactivating TOR in Δabl1 mutants or glucose-treated WT strains restored appressorium formation by promoting mitotic arrest at G1/G0 via an appressorium- and autophagy-inducing cell cycle delay at G2/M. Collectively, this work uncovers a novel glucose-ABL1-TOR signaling axis and shows it engages two metabolic checkpoints in order to modulate cell cycle tuning and mediate terminal appressorial cell differentiation. We thus provide new molecular insights into TOR regulation and cell development in response to glucose.

  6. Divergent regulation of Arabidopsis SAUR genes

    NARCIS (Netherlands)

    Mourik, van Hilda; Dijk, van Aalt D.J.; Stortenbeker, Niek; Angenent, Gerco C.; Bemer, Marian

    2017-01-01

    Background: Small Auxin-Upregulated RNA (SAUR) genes encode growth regulators that induce cell elongation. Arabidopsis contains more than 70 SAUR genes, of which the growth-promoting function has been unveiled in seedlings, while their role in other tissues remained largely unknown. Here, we

  7. Posttranscriptional Regulation of the Neurofibromatosis 2 Gene

    Science.gov (United States)

    2006-07-01

    signaling and division were downregulated, including an apoptosis - related, putative tumor suppressor gene, LUCA-15, which was downregulated in seven of... embryologically from the outgrowth of the developing brain (Martinez-Morales et al., 2004). It is comprised of two major layers, the inner layer (prospective...eight genes involved with cell signaling and division were down- regulated. These include an apoptosis -related, putative tumor suppressor gene LUCA-15

  8. Manipulation of Cell Cycle and Chromatin Configuration by Means of Cell-Penetrating Geminin.

    Directory of Open Access Journals (Sweden)

    Yoshinori Ohno

    Full Text Available Geminin regulates chromatin remodeling and DNA replication licensing which play an important role in regulating cellular proliferation and differentiation. Transcription of the Geminin gene is regulated via an E2F-responsive region, while the protein is being closely regulated by the ubiquitin-proteasome system. Our objective was to directly transduce Geminin protein into cells. Recombinant cell-penetrating Geminin (CP-Geminin was generated by fusing Geminin with a membrane translocating motif from FGF4 and was efficiently incorporated into NIH 3T3 cells and mouse embryonic fibroblasts. The withdrawal study indicated that incorporated CP-Geminin was quickly reduced after removal from medium. We confirmed CP-Geminin was imported into the nucleus after incorporation and also that the incorporated CP-Geminin directly interacted with Cdt1 or Brahma/Brg1 as the same manner as Geminin. We further demonstrated that incorporated CP-Geminin suppressed S-phase progression of the cell cycle and reduced nuclease accessibility in the chromatin, probably through suppression of chromatin remodeling, indicating that CP-Geminin constitutes a novel tool for controlling chromatin configuration and the cell cycle. Since Geminin has been shown to be involved in regulation of stem cells and cancer cells, CP-Geminin is expected to be useful for elucidating the role of Geminin in stem cells and cancer cells, and for manipulating their activity.

  9. Effect of specific silencing of EMMPRIN on the growth and cell cycle distribution of MCF-7 breast cancer cells.

    Science.gov (United States)

    Yang, X Q; Yang, J; Wang, R; Zhang, S; Tan, Q W; Lv, Q; Meng, W T; Mo, X M; Li, H J

    2015-12-02

    The extracellular matrix metalloproteinase inducer (EMMPRIN, CD147) is a member of the immunoglobulin family and shows increased expression in tumor cells. We examined the effect of RNAi-mediated EMMPRIN gene silencing induced by lentiviral on the growth and cycle distribution of MCF-7 breast cancer cells. Lentiviral expressing EMMPRIN-short hairpin RNA were packaged to infect MCF-7 cells. The inhibition efficiency of EMMPRIN was validated by real-time fluorescent quantitation polymerase chain reaction and western blotting. The effect of EMMPRIN on cell proliferation ability was detected using the MTT assay and clone formation experiments. Changes in cell cycle were detected by flow cytometry. EMMPRIN-short hairpin RNA-packaged lentiviral significantly down-regulated EMMPRIN mRNA and protein expression, significantly inhibited cell proliferation and in vitro tumorigenicity, and induced cell cycle abnormalities. Cells in the G0/G1 and G2/M phases were increased, while cells in the S phase were decreased after infection of MCF-7 cells for 3 days. The EMMPRIN gene facilitates breast cancer cell malignant proliferation by regulating cell cycle distribution and may be a molecular target for breast cancer gene therapy.

  10. Neutral space analysis for a Boolean network model of the fission yeast cell cycle network

    Directory of Open Access Journals (Sweden)

    Gonzalo A Ruz

    2014-01-01

    Full Text Available BACKGROUND: Interactions between genes and their products give rise to complex circuits known as gene regulatory networks (GRN that enable cells to process information and respond to external stimuli. Several important processes for life, depend of an accurate and context-specific regulation of gene expression, such as the cell cycle, which can be analyzed through its GRN, where deregulation can lead to cancer in animals or a directed regulation could be applied for biotechnological processes using yeast. An approach to study the robustness of GRN is through the neutral space. In this paper, we explore the neutral space of a Schizosaccharomyces pombe (fission yeast cell cycle network through an evolution strategy to generate a neutral graph, composed of Boolean regulatory networks that share the same state sequences of the fission yeast cell cycle. RESULTS: Through simulations it was found that in the generated neutral graph, the functional networks that are not in the wildtype connected component have in general a Hamming distance more than 3 with the wildtype, and more than 10 between the other disconnected functional networks. Significant differences were found between the functional networks in the connected component of the wildtype network and the rest of the network, not only at a topological level, but also at the state space level, where significant differences in the distribution of the basin of attraction for the G1 fixed point was found for deterministic updating schemes. CONCLUSIONS: In general, functional networks in the wildtype network connected component, can mutate up to no more than 3 times, then they reach a point of no return where the networks leave the connected component of the wildtype. The proposed method to construct a neutral graph is general and can be used to explore the neutral space of other biologically interesting networks, and also formulate new biological hypotheses studying the functional networks in the

  11. Cell cycle-dependent transcription factors control the expression of yeast telomerase RNA.

    Science.gov (United States)

    Dionne, Isabelle; Larose, Stéphanie; Dandjinou, Alain T; Abou Elela, Sherif; Wellinger, Raymund J

    2013-07-01

    Telomerase is a specialized ribonucleoprotein that adds repeated DNA sequences to the ends of eukaryotic chromosomes to preserve genome integrity. Some secondary structure features of the telomerase RNA are very well conserved, and it serves as a central scaffold for the binding of associated proteins. The Saccharomyces cerevisiae telomerase RNA, TLC1, is found in very low copy number in the cell and is the limiting component of the known telomerase holoenzyme constituents. The reasons for this low abundance are unclear, but given that the RNA is very stable, transcriptional control mechanisms must be extremely important. Here we define the sequences forming the TLC1 promoter and identify the elements required for its low expression level, including enhancer and repressor elements. Within an enhancer element, we found consensus sites for Mbp1/Swi4 association, and chromatin immunoprecipitation (ChIP) assays confirmed the binding of Mbp1 and Swi4 to these sites of the TLC1 promoter. Furthermore, the enhancer element conferred cell cycle-dependent regulation to a reporter gene, and mutations in the Mbp1/Swi4 binding sites affected the levels of telomerase RNA and telomere length. Finally, ChIP experiments using a TLC1 RNA-binding protein as target showed cell cycle-dependent transcription of the TLC1 gene. These results indicate that the budding yeast TLC1 RNA is transcribed in a cell cycle-dependent fashion late in G1 and may be part of the S phase-regulated group of genes involved in DNA replication.

  12. Indole-3-carbinol induces G1 cell cycle arrest and apoptosis through aryl hydrocarbon receptor in THP-1 monocytic cell line.

    Science.gov (United States)

    Mohammadi, Saeed; Seyedhosseini, Fakhri Sadat; Behnampour, Nasser; Yazdani, Yaghoub

    2017-10-01

    The role of aryl hydrocarbon receptor (AhR) in carcinogenesis has been studied recently. Indole-3-carbinol (I3C) is an AhR agonist and a potential anticancer agent. Here, we investigated the effects of I3C on cell cycle progression and apoptosis through activation of AhR on THP-1 acute myeloid leukemia (AML) cell line. MTT viability assay was used to measure the cytotoxic effects of I3C on THP-1 cells. Apoptosis and cell cycle assays were investigated using flow cytometry. Real time RT-PCR was conducted to measure the alterations in the expression of AhR gene, key genes associated with AhR activation (IL1β and CYP1A1) and major genes involved in cell cycle regulation and apoptosis including P27, P21, CDK2, P53, BCL2 and FasR. Our findings revealed that I3C inhibits the proliferation of THP-1 cells in a dose- and time-dependent manner with minimal toxicity over normal monocytes. The AhR target genes (CYP1A1, IL1β) were overexpressed upon I3C treatment (p cycle arrest was also observed using flow cytometry. G1-acting cell cycle genes (P21, P27 and P53) were overexpressed (p cycle arrest in a dose- and time-dependent manner. Therefore, AhR could be targeted as a novel treatment possibility in AML.

  13. Identification and Regulation of c-Myb Target Genes in MCF-7 Cells

    International Nuclear Information System (INIS)

    Quintana, Anita M; Liu, Fan; O'Rourke, John P; Ness, Scott A

    2011-01-01

    The c-Myb transcription factor regulates differentiation and proliferation in hematopoietic cells, stem cells and epithelial cells. Although oncogenic versions of c-Myb were first associated with leukemias, over expression or rearrangement of the c-myb gene is common in several types of solid tumors, including breast cancers. Expression of the c-myb gene in human breast cancer cells is dependent on estrogen stimulation, but little is known about the activities of the c-Myb protein or what genes it regulates in estrogen-stimulated cells. We used chromatin immunoprecipitation coupled with whole genome promoter tiling microarrays to identify endogenous c-Myb target genes in human MCF-7 breast cancer cells and characterized the activity of c-Myb at a panel of target genes during different stages of estrogen deprivation and stimulation. By using different antibodies and different growth conditions, the c-Myb protein was found associated with over 10,000 promoters in MCF-7 cells, including many genes that encode cell cycle regulators or transcription factors and more than 60 genes that encode microRNAs. Several previously identified c-Myb target genes were identified, including CCNB1, MYC and CXCR4 and novel targets such as JUN, KLF4, NANOG and SND1. By studying a panel of these targets to validate the results, we found that estradiol stimulation triggered the association of c-Myb with promoters and that association correlated with increased target gene expression. We studied one target gene, CXCR4, in detail, showing that c-Myb associated with the CXCR4 gene promoter and activated a CXCR4 reporter gene in transfection assays. Our results show that c-Myb associates with a surprisingly large number of promoters in human cells. The results also suggest that estradiol stimulation leads to large-scale, genome-wide changes in c-Myb activity and subsequent changes in gene expression in human breast cancer cells

  14. Fisetin and hesperetin induced apoptosis and cell cycle arrest in chronic myeloid leukemia cells accompanied by modulation of cellular signaling.

    Science.gov (United States)

    Adan, Aysun; Baran, Yusuf

    2016-05-01

    Fisetin and hesperetin, naturally occurring flavonoids, have been reported as novel antioxidants with chemopreventive/chemotherapeutic potential against various types of cancer. However, their mechanism of action in CML is still unknown. This particular study aims to evaluate the therapeutic potentials of fisetin and hesperetin and their effects on cell proliferation, apoptosis, and cell cycle progression in human K562 CML cells. The results indicated that fisetin and hesperetin inhibited cell proliferation and triggered programmed cell death in these cells. The latter was confırmed by mitochondrial membrane depolarization and an increase in caspase-3 activation. In addition to that, we have detected S and G2/M cell cycle arrests and G0/G1 arrest upon fisetin and hesperetin treatment, respectively. To identify the altered genes and genetic networks in response to fisetin and hesperetin, whole-genome microarray analysis was performed. The microarray gene profiling analysis revealed some important signaling pathways including JAK/STAT pathway, KIT receptor signaling, and growth hormone receptor signaling that were altered upon fisetin and hesperetin treatment. Moreover, microarray data suggested potential candidate genes for targeted CML therapy. Fisetin and hesperetin significantly modulated the expression of genes involved in cell proliferation and division, apoptosis, cell cycle regulation, and other significant cellular processes such as replication, transcription, and translation. In conclusion, our results suggest that fisetin and hesperetin as potential natural agents for CML therapy.

  15. Heterogenic final cell cycle by chicken retinal Lim1 horizontal progenitor cells leads to heteroploid cells with a remaining replicated genome.

    Directory of Open Access Journals (Sweden)

    Shahrzad Shirazi Fard

    Full Text Available Retinal progenitor cells undergo apical mitoses during the process of interkinetic nuclear migration and newly generated post-mitotic neurons migrate to their prospective retinal layer. Whereas this is valid for most types of retinal neurons, chicken horizontal cells are generated by delayed non-apical mitoses from dedicated progenitors. The regulation of such final cell cycle is not well understood and we have studied how Lim1 expressing horizontal progenitor cells (HPCs exit the cell cycle. We have used markers for S- and G2/M-phase in combination with markers for cell cycle regulators Rb1, cyclin B1, cdc25C and p27Kip1 to characterise the final cell cycle of HPCs. The results show that Lim1+ HPCs are heterogenic with regards to when and during what phase they leave the final cell cycle. Not all horizontal cells were generated by a non-apical (basal mitosis; instead, the HPCs exhibited three different behaviours during the final cell cycle. Thirty-five percent of the Lim1+ horizontal cells was estimated to be generated by non-apical mitoses. The other horizontal cells were either generated by an interkinetic nuclear migration with an apical mitosis or by a cell cycle with an S-phase that was not followed by any mitosis. Such cells remain with replicated DNA and may be regarded as somatic heteroploids. The observed heterogeneity of the final cell cycle was also seen in the expression of Rb1, cyclin B1, cdc25C and p27Kip1. Phosphorylated Rb1-Ser608 was restricted to the Lim1+ cells that entered S-phase while cyclin B1 and cdc25C were exclusively expressed in HPCs having a basal mitosis. Only HPCs that leave the cell cycle after an apical mitosis expressed p27Kip1. We speculate that the cell cycle heterogeneity with formation of heteroploid cells may present a cellular context that contributes to the suggested propensity of these cells to generate cancer when the retinoblastoma gene is mutated.

  16. Streptomyces sporulation - Genes and regulators involved in bacterial cell differentiation

    OpenAIRE

    Larsson, Jessica

    2010-01-01

    Streptomycetes are Gram-positive bacteria with a complex developmental life cycle. They form spores on specialized cells called aerial hyphae, and this sporulation involves alterations in growth, morphogenesis and cell cycle processes like cell division and chromosome segregation. Understanding the developmental mechanisms that streptomycetes have evolved for regulating for example cell division is of general interest in bacterial cell biology. It can also be valuable in the design of new dru...

  17. Solving the influence maximization problem reveals regulatory organization of the yeast cell cycle.

    Directory of Open Access Journals (Sweden)

    David L Gibbs

    2017-06-01

    Full Text Available The Influence Maximization Problem (IMP aims to discover the set of nodes with the greatest influence on network dynamics. The problem has previously been applied in epidemiology and social network analysis. Here, we demonstrate the application to cell cycle regulatory network analysis for Saccharomyces cerevisiae. Fundamentally, gene regulation is linked to the flow of information. Therefore, our implementation of the IMP was framed as an information theoretic problem using network diffusion. Utilizing more than 26,000 regulatory edges from YeastMine, gene expression dynamics were encoded as edge weights using time lagged transfer entropy, a method for quantifying information transfer between variables. By picking a set of source nodes, a diffusion process covers a portion of the network. The size of the network cover relates to the influence of the source nodes. The set of nodes that maximizes influence is the solution to the IMP. By solving the IMP over different numbers of source nodes, an influence ranking on genes was produced. The influence ranking was compared to other metrics of network centrality. Although the top genes from each centrality ranking contained well-known cell cycle regulators, there was little agreement and no clear winner. However, it was found that influential genes tend to directly regulate or sit upstream of genes ranked by other centrality measures. The influential nodes act as critical sources of information flow, potentially having a large impact on the state of the network. Biological events that affect influential nodes and thereby affect information flow could have a strong effect on network dynamics, potentially leading to disease. Code and data can be found at: https://github.com/gibbsdavidl/miergolf.

  18. Solving the influence maximization problem reveals regulatory organization of the yeast cell cycle

    Science.gov (United States)

    Shmulevich, Ilya

    2017-01-01

    The Influence Maximization Problem (IMP) aims to discover the set of nodes with the greatest influence on network dynamics. The problem has previously been applied in epidemiology and social network analysis. Here, we demonstrate the application to cell cycle regulatory network analysis for Saccharomyces cerevisiae. Fundamentally, gene regulation is linked to the flow of information. Therefore, our implementation of the IMP was framed as an information theoretic problem using network diffusion. Utilizing more than 26,000 regulatory edges from YeastMine, gene expression dynamics were encoded as edge weights using time lagged transfer entropy, a method for quantifying information transfer between variables. By picking a set of source nodes, a diffusion process covers a portion of the network. The size of the network cover relates to the influence of the source nodes. The set of nodes that maximizes influence is the solution to the IMP. By solving the IMP over different numbers of source nodes, an influence ranking on genes was produced. The influence ranking was compared to other metrics of network centrality. Although the top genes from each centrality ranking contained well-known cell cycle regulators, there was little agreement and no clear winner. However, it was found that influential genes tend to directly regulate or sit upstream of genes ranked by other centrality measures. The influential nodes act as critical sources of information flow, potentially having a large impact on the state of the network. Biological events that affect influential nodes and thereby affect information flow could have a strong effect on network dynamics, potentially leading to disease. Code and data can be found at: https://github.com/gibbsdavidl/miergolf. PMID:28628618

  19. Solving the influence maximization problem reveals regulatory organization of the yeast cell cycle.

    Science.gov (United States)

    Gibbs, David L; Shmulevich, Ilya

    2017-06-01

    The Influence Maximization Problem (IMP) aims to discover the set of nodes with the greatest influence on network dynamics. The problem has previously been applied in epidemiology and social network analysis. Here, we demonstrate the application to cell cycle regulatory network analysis for Saccharomyces cerevisiae. Fundamentally, gene regulation is linked to the flow of information. Therefore, our implementation of the IMP was framed as an information theoretic problem using network diffusion. Utilizing more than 26,000 regulatory edges from YeastMine, gene expression dynamics were encoded as edge weights using time lagged transfer entropy, a method for quantifying information transfer between variables. By picking a set of source nodes, a diffusion process covers a portion of the network. The size of the network cover relates to the influence of the source nodes. The set of nodes that maximizes influence is the solution to the IMP. By solving the IMP over different numbers of source nodes, an influence ranking on genes was produced. The influence ranking was compared to other metrics of network centrality. Although the top genes from each centrality ranking contained well-known cell cycle regulators, there was little agreement and no clear winner. However, it was found that influential genes tend to directly regulate or sit upstream of genes ranked by other centrality measures. The influential nodes act as critical sources of information flow, potentially having a large impact on the state of the network. Biological events that affect influential nodes and thereby affect information flow could have a strong effect on network dynamics, potentially leading to disease. Code and data can be found at: https://github.com/gibbsdavidl/miergolf.

  20. Cell Cycle Control in the Early Embryonic Development of Aquatic Animal Species

    Science.gov (United States)

    Siefert, Joseph C.; Clowdus, Emily A.; Sansam, Christopher L.

    2016-01-01

    The cell cycle is integrated with many aspects of embryonic development. Not only is proper control over the pace of cell proliferation important, but also the timing of cell cycle progression is coordinated with transcription, cell migration, and cell differentiation. Due to the ease with which the embryos of aquatic organisms can be observed and manipulated, they have been a popular choice for embryologists throughout history. In the cell cycle field, aquatic organisms have been extremely important because they have played a major role in the discovery and analysis of key regulators of the cell cycle. In particular, the frog Xenopus laevis has been instrumental for understanding how the basic embryonic cell cycle is regulated. More recently, the zebrafish has been used to understand how the cell cycle is remodeled during vertebrate development and how it is regulated during morphogenesis. This review describes how some of the unique strengths of aquatic species have been leveraged for cell cycle research and suggests how species such as Xenopus and zebrafish will continue to reveal the roles of the cell cycle in human biology and disease. PMID:26475527

  1. Conserved CDC20 cell cycle functions are carried out by two of the five isoforms in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Zoltán Kevei

    Full Text Available The CDC20 and Cdh1/CCS52 proteins are substrate determinants and activators of the Anaphase Promoting Complex/Cyclosome (APC/C E3 ubiquitin ligase and as such they control the mitotic cell cycle by targeting the degradation of various cell cycle regulators. In yeasts and animals the main CDC20 function is the destruction of securin and mitotic cyclins. Plants have multiple CDC20 gene copies whose functions have not been explored yet. In Arabidopsis thaliana there are five CDC20 isoforms and here we aimed at defining their contribution to cell cycle regulation, substrate selectivity and plant development.Studying the gene structure and phylogeny of plant CDC20s, the expression of the five AtCDC20 gene copies and their interactions with the APC/C subunit APC10, the CCS52 proteins, components of the mitotic checkpoint complex (MCC and mitotic cyclin substrates, conserved CDC20 functions could be assigned for AtCDC20.1 and AtCDC20.2. The other three intron-less genes were silent and specific for Arabidopsis. We show that AtCDC20.1 and AtCDC20.2 are components of the MCC and interact with mitotic cyclins with unexpected specificity. AtCDC20.1 and AtCDC20.2 are expressed in meristems, organ primordia and AtCDC20.1 also in pollen grains and developing seeds. Knocking down both genes simultaneously by RNAi resulted in severe delay in plant development and male sterility. In these lines, the meristem size was reduced while the cell size and ploidy levels were unaffected indicating that the lower cell number and likely slowdown of the cell cycle are the cause of reduced plant growth.The intron-containing CDC20 gene copies provide conserved and redundant functions for cell cycle progression in plants and are required for meristem maintenance, plant growth and male gametophyte formation. The Arabidopsis-specific intron-less genes are possibly "retrogenes" and have hitherto undefined functions or are pseudogenes.

  2. Regulation of meiotic gene expression in plants

    Directory of Open Access Journals (Sweden)

    Adele eZhou

    2014-08-01

    <