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Gupta S, Ahmed MM. Targeting radiation-induced upstream stimulatory factor-1 by histone deacetylase inhibitors to reverse radioresistance in prostate cancer. Cancer Rep (Hoboken) 2021; 5:e1553. [PMID: 34533293 PMCID: PMC9780427 DOI: 10.1002/cnr2.1553] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 08/11/2021] [Accepted: 08/23/2021] [Indexed: 01/25/2023] Open
Abstract
BACKGROUND Ionizing radiation (IR) is a standard modality for the management of solid tumors. Apart from its killing effects, IR can induce pro-survival factors leading to radioresistance of cancer. Mechanistic understanding of radiation resistance is warranted to overcome the pro-survival effects of IR. AIM The aim of this study was to investigate the role of upstream stimulatory factor-1 (USF-1) in the induction of radioresistance in prostate cancer and its targeting by histone deacetylase (HDAC) inhibitors to reverse resistance. METHODS AND RESULTS This study reports here that USF-1 is a marker for radioresistance in PC-3 cells. Using protein-DNA array analysis, it was documented that DNA binding activity of USF-1 was elevated following IR in PC-3 cells. Novel HDAC inhibitors downregulated USF-1 binding either alone or in combination with IR. A 5 Gy dose of IR induced the expression of target genes of USF-1 (human telomerase reverse transcriptase [hTERT], IGF2R, CyclinB1, and Cdk1), however, HDAC inhibitors alone or in combination with IR reduced their expression as measured by real time RT PCR analysis. Furthermore, immunofluorescence analysis revealed that while USF-1 localized primarily in the nucleus following IR, it localized in the cytoplasm when treated with HDAC inhibitors/combination. Maximum effects of modulation of USF-1 expression (overexpression or suppression) were observed on hTERT activity as determined by dual-luciferase reporter assay. To further confirm the role of USF-1 in radioresistance, cell growth was analyzed using the real-time cell electronic sensing (RT-CES) system. This study found that USF-1-transfected cells proliferated faster than the vector-transfected cells with or without treatments with HDAC inhibitors/IR/combination. Colony forming assay also confirmed that USF-1 overexpression led to increased survival following IR. Importantly, colony-forming assay demonstrated that HDAC inhibitors reversed the radioresistance in both PC-3 and DU-145 cells. CONCLUSION These studies demonstrate that HDAC inhibitors reverse the radioresistance in prostate cancer through down-modulation of USF-1-mediated transactivation of target genes involved in cell proliferation and cell cycle.
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Affiliation(s)
- Seema Gupta
- Department of Radiation OncologyUniversity of MiamiMiamiFloridaUSA,Present address:
The Loop Immuno‐Oncology Laboratory, Lombardi Comprehensive Cancer CenterGeorgetown University Medical CenterWashington, DCUSA
| | - Mansoor M. Ahmed
- Department of Radiation OncologyUniversity of MiamiMiamiFloridaUSA,Present address:
Radiation Research Program (RRP), Division of Cancer Treatment and Diagnosis (DCTD)National Cancer Institute/National Institutes of HealthRockvilleMarylandUSA
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2
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Anger M, Radonova L, Horakova A, Sekach D, Charousova M. Impact of Global Transcriptional Silencing on Cell Cycle Regulation and Chromosome Segregation in Early Mammalian Embryos. Int J Mol Sci 2021; 22:9073. [PMID: 34445775 PMCID: PMC8396661 DOI: 10.3390/ijms22169073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 08/14/2021] [Accepted: 08/18/2021] [Indexed: 11/17/2022] Open
Abstract
The onset of an early development is, in mammals, characterized by profound changes of multiple aspects of cellular morphology and behavior. These are including, but not limited to, fertilization and the merging of parental genomes with a subsequent transition from the meiotic into the mitotic cycle, followed by global changes of chromatin epigenetic modifications, a gradual decrease in cell size and the initiation of gene expression from the newly formed embryonic genome. Some of these important, and sometimes also dramatic, changes are executed within the period during which the gene transcription is globally silenced or not progressed, and the regulation of most cellular activities, including those mentioned above, relies on controlled translation. It is known that the blastomeres within an early embryo are prone to chromosome segregation errors, which might, when affecting a significant proportion of a cell within the embryo, compromise its further development. In this review, we discuss how the absence of transcription affects the transition from the oocyte to the embryo and what impact global transcriptional silencing might have on the basic cell cycle and chromosome segregation controlling mechanisms.
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Affiliation(s)
- Martin Anger
- Central European Institute of Technology, Department of Genetics and Reproduction, Veterinary Research Institute, 621 00 Brno, Czech Republic; (L.R.); (A.H.); (D.S.); (M.C.)
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3
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Martínez-Alonso D, Malumbres M. Mammalian cell cycle cyclins. Semin Cell Dev Biol 2020; 107:28-35. [PMID: 32334991 DOI: 10.1016/j.semcdb.2020.03.009] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 03/27/2020] [Accepted: 03/31/2020] [Indexed: 12/23/2022]
Abstract
Proper progression throughout the cell division cycle depends on the expression level of a family of proteins known as cyclins, and the subsequent activation of cyclin-dependent kinases (Cdks). Among the numerous members of the mammalian cyclin family, only a few of them, cyclins A, B, C, D and E, are known to display critical roles in the cell cycle. These functions will be reviewed here with a special focus on their relevance in different cell types in vivo and their implications in human disease.
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Affiliation(s)
- Diego Martínez-Alonso
- Cell Division and Cancer Group, Spanish National Cancer Research Centre (CNIO) Madrid, Spain.
| | - Marcos Malumbres
- Cell Division and Cancer Group, Spanish National Cancer Research Centre (CNIO) Madrid, Spain.
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4
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Mouawad R, Himadewi P, Kadiyala D, Arnosti DN. Selective repression of the Drosophila cyclin B promoter by retinoblastoma and E2F proteins. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1863:194549. [PMID: 32275964 DOI: 10.1016/j.bbagrm.2020.194549] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 03/27/2020] [Accepted: 04/03/2020] [Indexed: 02/06/2023]
Abstract
The Cyclin B1 gene encodes a G2/M cyclin that is deregulated in various human cancers, however, the transcriptional regulation of this gene is incompletely understood. The E2F and retinoblastoma family of proteins are involved in this gene's regulation, but there is disagreement on which of the E2F and retinoblastoma proteins interact with the promoter to regulate this gene. Here, we dissect the promoter region of the Drosophila CycB gene, and study the role of Rbf and E2F factors in its regulation. This gene exhibits remarkable features that distinguish it from G1/S regulated promoters, such as PCNA. The promoter is comprised of modular elements with dedicated repressor and activator functions, including a segment spanning the first intron that interferes with a 5' activator element. A highly active minimal promoter (-464, +100) is repressed by the Rbf1 retinoblastoma protein, but much more potently repressed by the Rbf2 protein, which has been linked in other studies to control of cell growth genes. Unlike many other cell-cycle genes, which are activated by E2F1 and repressed by E2F2, CycB is potently activated by E2F2, and repressed by E2F1. Although the bulk of Rbf binding is associated with a region 5' of the core promoter, E2F and retinoblastoma proteins functionally interact with the basal promoter region, in part through a conserved E2F site at -80 bp. The specific regulatory requirements of this late cell cycle promoter appear to be linked to the unique activities of E2F and retinoblastoma family members acting on a complex cis-regulatory circuit.
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Affiliation(s)
- Rima Mouawad
- Graduate Program in Cell and Molecular Biology, Michigan State University, East Lansing, MI 48824, United States of America.
| | - Pamela Himadewi
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, United States of America
| | - Dhruva Kadiyala
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, United States of America
| | - David N Arnosti
- Graduate Program in Cell and Molecular Biology, Michigan State University, East Lansing, MI 48824, United States of America; Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, United States of America.
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5
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Farshadi E, Yan J, Leclere P, Goldbeter A, Chaves I, van der Horst GTJ. The positive circadian regulators CLOCK and BMAL1 control G2/M cell cycle transition through Cyclin B1. Cell Cycle 2019; 18:16-33. [PMID: 30558467 PMCID: PMC6343743 DOI: 10.1080/15384101.2018.1558638] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 11/23/2018] [Accepted: 11/26/2018] [Indexed: 01/09/2023] Open
Abstract
We previously identified a tight bidirectional phase coupling between the circadian clock and the cell cycle. To understand the role of the CLOCK/BMAL1 complex, representing the main positive regulator of the circadian oscillator, we knocked down Bmal1 or Clock in NIH3T33C mouse fibroblasts (carrying fluorescent reporters for clock and cell cycle phase) and analyzed timing of cell division in individual cells and cell populations. Inactivation of Bmal1 resulted in a loss of circadian rhythmicity and a lengthening of the cell cycle, originating from delayed G2/M transition. Subsequent molecular analysis revealed reduced levels of Cyclin B1, an important G2/M regulator, upon suppression of Bmal1 gene expression. In complete agreement with these experimental observations, simulation of Bmal1 knockdown in a computational model for coupled mammalian circadian clock and cell cycle oscillators (now incorporating Cyclin B1 induction by BMAL1) revealed a lengthening of the cell cycle. Similar data were obtained upon knockdown of Clock gene expression. In conclusion, the CLOCK/BMAL1 complex controls cell cycle progression at the level of G2/M transition through regulation of Cyclin B1 expression.
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Affiliation(s)
- Elham Farshadi
- Department of Molecular Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Jie Yan
- Unit of Theoretical Chronobiology, Faculty of Sciences, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Pierre Leclere
- Department of Molecular Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Albert Goldbeter
- Unit of Theoretical Chronobiology, Faculty of Sciences, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Inês Chaves
- Department of Molecular Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
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Tan Y, Chen Y, Du M, Peng Z, Xie P. USF2 inhibits the transcriptional activity of Smurf1 and Smurf2 to promote breast cancer tumorigenesis. Cell Signal 2018; 53:49-58. [PMID: 30244169 DOI: 10.1016/j.cellsig.2018.09.013] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Revised: 09/16/2018] [Accepted: 09/19/2018] [Indexed: 10/28/2022]
Abstract
Smurf1 (Smad ubiquitylation regulatory factor 1) and Smurf2 are negative regulators of the TGF-β (transforming growth factor-β) pathway. The protein stability and ubiquitin E3 activity regulation of Smurfs have been well studied. However, the mechanism of Smurfs expression at the transcriptional level remains uncharacterized. Here, we reported that USF2 (upstream stimulatory factor 2), a basic helix-loop-helix-leucine-zip transcription factor, is necessary for the transcriptional activity of Smurf1 and Smurf2. The 5'-flanking sequences of the Smurfs gene have more than one E-box motifs, and USF2 bounds the Smurfs promoter in vitro and in vivo. Over-expression USF2 inhibited the transcriptional activity of the Smurfs, and Smurfs mRNA was markedly decreased. Therefore, the activity of TGF-β was distinctly enhanced. Furthermore, in human breast cancers, USF2 was abnormally high expressed and correlated with cancer progression. USF2 was specifically inversely correlated with Smurfs in Luminal A subtype breast cancer patients. These findings suggest the mechanism regulation of Smurfs transcriptional activity, and shed new light on the cancer-promoting role of USF2.
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Affiliation(s)
- Yawen Tan
- Department of Breast and Thyroid Surgery, The Second People's Hospital of Shenzhen, Guangdong 518035, China
| | - Yujiao Chen
- Department of Biochemistry and Molecular Biology, Capital Medical University, Beijing 100069, China; Beijing Key Laboratory for Cancer Invasion and Metastasis Research, Capital Medical University, Beijing 100069, China
| | - Mengge Du
- Department of Biochemistry and Molecular Biology, Capital Medical University, Beijing 100069, China; Beijing Key Laboratory for Cancer Invasion and Metastasis Research, Capital Medical University, Beijing 100069, China
| | - Zhiqiang Peng
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center of Protein Sciences (Beijing), Beijing Institute of Lifeomics, Beijing, China.
| | - Ping Xie
- Department of Biochemistry and Molecular Biology, Capital Medical University, Beijing 100069, China; Beijing Key Laboratory for Cancer Invasion and Metastasis Research, Capital Medical University, Beijing 100069, China.
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Agostini A, Brunetti M, Davidson B, Göran Tropé C, Heim S, Panagopoulos I, Micci F. Identification of novel cyclin gene fusion transcripts in endometrioid ovarian carcinomas. Int J Cancer 2018; 143:1379-1387. [PMID: 29633253 PMCID: PMC6099316 DOI: 10.1002/ijc.31418] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 03/14/2018] [Accepted: 03/20/2018] [Indexed: 12/16/2022]
Abstract
Formation of fusion genes is pathogenetically crucial in many solid tumors. They are particularly characteristic of several mesenchymal tumors, but may also be found in epithelial neoplasms. Ovarian carcinomas, too, may harbor fusion genes but only few of these were found to be recurrent with a rate ranging from 0.5 to 5%. Because most attempts to find specific and recurrent fusion transcripts in ovarian carcinomas focused exclusively on high‐grade serous carcinomas, the situation in the other carcinoma subgroups remains largely uninvestigated as far as fusion genes are concerned. We performed transcriptome sequencing on a series of 34 samples from ovarian tumors that included borderline, clear cell, mucinous, endometrioid, low‐grade and high‐grade serous carcinomas in search of fusion genes typical of these subtypes. We found a total of 24 novel fusion transcripts. The PCMTDI‐CCNL2 fusion transcript, which involves a member of the cyclin family, was found recurrently involved but only in endometrioid carcinomas (4 of 18 tumors; 22%). We also found three additional fusion transcripts involving genes belonging to the cyclin family: ANXA5‐CCNA2 and PDE4D‐CCNB1 were detected in two endometrioid carcinomas, whereas CCNY‐NRG4 was identified in a clear cell carcinoma. The recurrent involvement of CCNL2 in four fusions and of three other genes of the cyclin family in three additional transcripts hints that deregulation of cyclin genes is important in the pathogenesis of ovarian carcinomas in general but of endometrioid carcinomas particularly. What's new? Chimeric genes formed by fusion of previously separate genes are associated with many malignant tumors, but rare in ovarian cancer. Here the authors performed transcriptome sequencing of different types of ovarian tumors and identify novel fusion genes, involving cyclin genes, the master regulators of the cell cycle. As most of these fusions were found in ovarian cancer of the endometroid type, which represent about 10% of all ovarian cancers, the data point to a novel role of cyclin deregulation in this specific cancer subtype.
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Affiliation(s)
- Antonio Agostini
- Section for Cancer Cytogenetics, Institute for Cancer Genetics and Informatics, The Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway
| | - Marta Brunetti
- Section for Cancer Cytogenetics, Institute for Cancer Genetics and Informatics, The Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway
| | - Ben Davidson
- Department of Pathology, The Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway.,Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Claes Göran Tropé
- Department of Gynecology, The Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway
| | - Sverre Heim
- Section for Cancer Cytogenetics, Institute for Cancer Genetics and Informatics, The Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway.,Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Ioannis Panagopoulos
- Section for Cancer Cytogenetics, Institute for Cancer Genetics and Informatics, The Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway
| | - Francesca Micci
- Section for Cancer Cytogenetics, Institute for Cancer Genetics and Informatics, The Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway.,Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, Norway
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8
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Minute Virus of Mice Inhibits Transcription of the Cyclin B1 Gene during Infection. J Virol 2017; 91:JVI.00428-17. [PMID: 28446681 DOI: 10.1128/jvi.00428-17] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 04/22/2017] [Indexed: 12/24/2022] Open
Abstract
Replication of minute virus of mice (MVM) induces a sustained cellular DNA damage response (DDR) which the virus then exploits to prepare the nuclear environment for effective parvovirus takeover. An essential aspect of the MVM-induced DDR is the establishment of a potent premitotic block, which we previously found to be independent of activated p21 and ATR/Chk1 signaling. This arrest, unlike others reported previously, depends upon a significant, specific depletion of cyclin B1 and its encoding RNA, which precludes cyclin B1/CDK1 complex function, thus preventing mitotic entry. We show here that while the stability of cyclin B1 RNA was not affected by MVM infection, the production of nascent cyclin B1 RNA was substantially diminished at late times postinfection. Ectopic expression of NS1 alone did not reduce cyclin B1 expression. MVM infection also reduced the levels of cyclin B1 protein, and RNA levels normally increased in response to DNA-damaging reagents. We demonstrated that at times of reduced cyclin B1 expression during infection, there was a significantly reduced occupancy of RNA polymerase II and the essential mitotic transcription factor FoxM1 on the cyclin B1 gene promoter. Additionally, while total FoxM1 levels remained constant, there was a significant decrease of the phosphorylated, likely active, forms of FoxM1. Targeting of a constitutively active FoxM1 construct or the activation domain of FoxM1 to the cyclin B1 gene promoter via clustered regularly interspaced short palindromic repeats (CRISPR)-enzymatically inactive Cas9 in MVM-infected cells increased both cyclin B1 protein and RNA levels, implicating FoxM1 as a critical target for cyclin B1 inhibition during MVM infection.IMPORTANCE Replication of the parvovirus minute virus of mice (MVM) induces a sustained cellular DNA damage response (DDR) which the virus exploits to prepare the nuclear environment for effective takeover. An essential aspect of the MVM-induced DDR is establishment of a potent premitotic block. This block depends upon a significant, specific depletion of cyclin B1 and its encoding RNA that precludes cyclin B1/CDK1 complex functions necessary for mitotic entry. We show that reduced cyclin B1 expression is controlled primarily at the level of transcription initiation. Additionally, the essential mitotic transcription factor FoxM1 and RNA polymerase II were found to occupy the cyclin B1 gene promoter at reduced levels during infection. Recruiting a constitutively active FoxM1 construct or the activation domain of FoxM1 to the cyclin B1 gene promoter via CRISPR-catalytically inactive Cas9 (dCas9) in MVM-infected cells increased expression of both cyclin B1 protein and RNA, implicating FoxM1 as a critical target mediating MVM-induced cyclin B1 inhibition.
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Dambroise E, Simion M, Bourquard T, Bouffard S, Rizzi B, Jaszczyszyn Y, Bourge M, Affaticati P, Heuzé A, Jouralet J, Edouard J, Brown S, Thermes C, Poupon A, Reiter E, Sohm F, Bourrat F, Joly JS. Postembryonic Fish Brain Proliferation Zones Exhibit Neuroepithelial-Type Gene Expression Profile. Stem Cells 2017; 35:1505-1518. [PMID: 28181357 DOI: 10.1002/stem.2588] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 12/19/2016] [Accepted: 12/20/2016] [Indexed: 01/04/2023]
Abstract
In mammals, neuroepithelial cells play an essential role in embryonic neurogenesis, whereas glial stem cells are the principal source of neurons at postembryonic stages. By contrast, neuroepithelial-like stem/progenitor (NE) cells have been shown to be present throughout life in teleosts. We used three-dimensional (3D) reconstructions of cleared transgenic wdr12:GFP medaka brains to demonstrate that this cell type is widespread in juvenile and to identify new regions containing NE cells. We established the gene expression profile of optic tectum (OT) NE cells by cell sorting followed by RNA-seq. Our results demonstrate that most OT NE cells are indeed active stem cells and that some of them exhibit long G2 phases. We identified several novel pathways (e.g., DNA repair pathways) potentially involved in NE cell homeostasis. In situ hybridization studies showed that all NE populations in the postembryonic medaka brain have a similar molecular signature. Our findings highlight the importance of NE progenitors in medaka and improve our understanding of NE-cell biology. These cells are potentially useful not only for neural stem cell studies but also for improving the characterization of neurodevelopmental diseases, such as microcephaly. Stem Cells 2017;35:1505-1518.
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Affiliation(s)
- Emilie Dambroise
- INRA CASBAH Group, Neuro-PSI, UMR 9197, CNRS, Gif-sur-Yvette, France
| | - Matthieu Simion
- INRA CASBAH Group, Neuro-PSI, UMR 9197, CNRS, Gif-sur-Yvette, France
| | | | | | - Barbara Rizzi
- Tefor Core Facility, TEFOR Infrastructure, Neuro-PSI, CNRS, Gif-sur-Yvette, France
| | | | | | - Pierre Affaticati
- Tefor Core Facility, TEFOR Infrastructure, Neuro-PSI, CNRS, Gif-sur-Yvette, France
| | - Aurélie Heuzé
- INRA CASBAH Group, Neuro-PSI, UMR 9197, CNRS, Gif-sur-Yvette, France
| | - Julia Jouralet
- Plateforme BM-Gif, Imagif, UMR 9198, CNRS, Gif-sur-Yvette, France
| | - Joanne Edouard
- UMS AMAGEN CNRS, INRA, Université Paris-Saclay, Gif-sur-Yvette, France
| | | | | | | | | | - Frédéric Sohm
- UMS AMAGEN CNRS, INRA, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Franck Bourrat
- INRA CASBAH Group, Neuro-PSI, UMR 9197, CNRS, Gif-sur-Yvette, France
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Yuan Q, Bu Q, Li G, Zhang J, Cui T, Zhu R, Mu D. Association between single nucleotide polymorphisms of upstream transcription factor 1 (USF1) and susceptibility to papillary thyroid cancer. Clin Endocrinol (Oxf) 2016; 84:564-70. [PMID: 26052935 DOI: 10.1111/cen.12832] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Revised: 01/02/2015] [Accepted: 06/01/2015] [Indexed: 11/27/2022]
Abstract
BACKGROUND Thyroid cancer, predominantly by papillary thyroid cancer (PTC), is a malignant tumour of endocrine system with increasing incidence rate worldwide. Upstream transcription factor 1 (USF1) regulates a variety of biological processes by transactivation of functional genes. In this study, we investigated the association between USF1 polymorphisms and PTC risk. MATERIAL & METHODS A total of 334 patients with PTC, 186 patients with benign nodules (BN) and 668 healthy controls were enrolled in our study. Tag-SNPs were identified in Chinese Han in Beijing (CHB) from International HapMap Project Databases. Genomic DNAs were extracted by TaqMan Blood DNA kits. SNPs of USF1 were genotyped by TaqMan SNPs genotyping assay. Odds ratios (OR) and corresponding 95% confidence interval (CI) were used to assess the association between USF1 genetic variants and PTC risk. The statistical analyses were carried out with spss 13.0 software. RESULTS Five tag-SNPs were retrieved to capture all the genetic variants of USF1. Among the five tag-SNPs, genetic variants in rs2516838, rs3737787 and rs2516839 have significant association with PTC risk. The rs2516838 polymorphisms dominant model (CG+GG vs CC: OR = 0·71; 95% CI: 0·52-0·97; P = 0·033) and allelic model (C vs G: OR = 0·031; 95% CI: 0·56-0·97; P = 0·031) indicated it may act as a protective factor against PTC. On the contrary, the results of rs3737787 polymorphisms: dominant model (CT+TT vs CC: OR = 1·55; 95%CI: 1·09-2·02; P = 0·001) and allelic model (C vs T: OR = 1·35; 95%CI: 1·10-1·64; P = 0·003), as well as the results of rs2516839 polymorphisms: dominant model (GA+AA vs GG: OR = 1·77; 95%CI: 1·31-2·38; P < 0·001) and allelic model (G vs A: OR = 1·36; 95%CI: 1·13-1·63; P = 0·014), revealed that they may act as risk factors for PTC. CONCLUSION In this study, we found the SNPs of rs2516838 (mutant G alleles vs wild C alleles), rs3737787 (mutant T alleles vs wild C alleles) and rs2516839 (mutant A alleles vs wild G alleles) were significantly associated with PTC risk. Further large-scale studies with different ethnicities are still needed to validate our findings and explore the underlying mechanism of USF1 in PTC development.
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Affiliation(s)
- Qingzhong Yuan
- Department of Hepatobiliary Breast Thyroid Surgery, Shengli Oilfield Central Hospital, Dongying, China
| | - Qingao Bu
- Department of Hepatobiliary Breast Thyroid Surgery, Shengli Oilfield Central Hospital, Dongying, China
| | - Guoqiang Li
- Department of Hepatobiliary Breast Thyroid Surgery, Shengli Oilfield Central Hospital, Dongying, China
| | - Jun Zhang
- Department of Hepatobiliary Breast Thyroid Surgery, Shengli Oilfield Central Hospital, Dongying, China
| | - Tao Cui
- Department of Hepatobiliary Breast Thyroid Surgery, Shengli Oilfield Central Hospital, Dongying, China
| | - Rui Zhu
- Department of Hepatobiliary Breast Thyroid Surgery, Shengli Oilfield Central Hospital, Dongying, China
| | - Dongpo Mu
- Department of Hepatobiliary Breast Thyroid Surgery, Shengli Oilfield Central Hospital, Dongying, China
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Xiao X, Gang Y, Wang H, Wang J, Zhao L, Xu L, Liu Z. Double-stranded RNA transcribed from vector-based oligodeoxynucleotide acts as transcription factor decoy. Biochem Biophys Res Commun 2014; 457:221-6. [PMID: 25550185 DOI: 10.1016/j.bbrc.2014.12.091] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 12/20/2014] [Indexed: 12/24/2022]
Abstract
In this study, we designed a short hairpin RNA vector-based oligodeoxynucleotide (VB-ODN) carrying transcription factor (TF) consensus sequence which could function as a decoy to block TF activity. Specifically, VB-ODN for Nuclear factor-κB (NF-κB) could inhibit cell viability and decrease downstream gene expression in HEK293 cells without affecting expression of NF-κB itself. The specific binding between VB-ODN produced double-stranded RNA and NF-κB was evidenced by electrophoretic mobility shift assay. Moreover, similar VB-ODNs designed for three other TFs also inhibit their downstream gene expression but not that of themselves. Our study provides a new design of decoy for blocking TF activity.
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Affiliation(s)
- Xiao Xiao
- State Key Laboratory of Cancer Biology and Xijing Hospital of Digestive Diseases, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, Shaanxi Province, PR China
| | - Yi Gang
- State Key Laboratory of Cancer Biology and Xijing Hospital of Digestive Diseases, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, Shaanxi Province, PR China; Department of Infectious Diseases, Tangdu Hospital, Fourth Military Medical University, Xi'an 710038, Shaanxi Province, PR China
| | - Honghong Wang
- No. 518 Hospital of Chinese People's Liberation Army, Xi'an 710043, Shaanxi Province, PR China
| | - Jiayin Wang
- The Genome Institute, Washington University in St. Louis, St. Louis, MO 63108, USA
| | - Lina Zhao
- Department of Radiation Oncology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, Shaanxi Province, PR China
| | - Li Xu
- State Key Laboratory of Cancer Biology and Xijing Hospital of Digestive Diseases, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, Shaanxi Province, PR China.
| | - Zhiguo Liu
- State Key Laboratory of Cancer Biology and Xijing Hospital of Digestive Diseases, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, Shaanxi Province, PR China.
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12
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Derivation of a novel G2 reporter system. Cytotechnology 2014; 68:19-24. [PMID: 24981314 DOI: 10.1007/s10616-014-9757-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 06/07/2014] [Indexed: 12/30/2022] Open
Abstract
Progression through G2 phase of the cell cycle is a technically difficult area of cell biology to study due to the lack of physical markers specific to this phase. The FUCCI system uses the biology of the cell cycle to drive fluorescence in select phases of the cell cycle. Similarly, a commercially available system has used a fluorescent analog of the Cyclin B1 protein to visualize cells from late S phase to the metaphase-anaphase transition. We have modified these systems to use the promoter and destruction box elements of Cyclin B1 to drive a cyan fluorescent protein. We demonstrate here that this is a useful tool for measuring the length of G2 phase without perturbing any aspect of cell cycle progression.
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13
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Vallejo G, La Greca AD, Tarifa-Reischle IC, Mestre-Citrinovitz AC, Ballaré C, Beato M, Saragüeta P. CDC2 mediates progestin initiated endometrial stromal cell proliferation: a PR signaling to gene expression independently of its binding to chromatin. PLoS One 2014; 9:e97311. [PMID: 24859236 PMCID: PMC4032247 DOI: 10.1371/journal.pone.0097311] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Accepted: 04/17/2014] [Indexed: 01/11/2023] Open
Abstract
Although non-genomic steroid receptor pathways have been studied over the past decade, little is known about the direct gene expression changes that take place as a consequence of their activation. Progesterone controls proliferation of rat endometrial stromal cells during the peri-implantation phase of pregnancy. We showed that picomolar concentration of progestin R5020 mimics this control in UIII endometrial stromal cells via ERK1-2 and AKT activation mediated by interaction of Progesterone Receptor (PR) with Estrogen Receptor beta (ERb) and without transcriptional activity of endogenous PR and ER. Here we identify early downstream targets of cytoplasmic PR signaling and their possible role in endometrial stromal cell proliferation. Microarray analysis of global gene expression changes in UIII cells treated for 45 min with progestin identified 97 up- and 341 down-regulated genes. The most over-represented molecular functions were transcription factors and regulatory factors associated with cell proliferation and cell cycle, a large fraction of which were repressors down-regulated by hormone. Further analysis verified that progestins regulate Ccnd1, JunD, Usf1, Gfi1, Cyr61, and Cdkn1b through PR-mediated activation of ligand-free ER, ERK1-2 or AKT, in the absence of genomic PR binding. ChIP experiments show that progestin promoted the interaction of USF1 with the proximal promoter of the Cdc2 gene. Usf1 knockdown abolished Cdc2 progestin-dependent transcriptional regulation and cell proliferation, which also blocked Cdc2 knockdown. We conclude that progestin-induced proliferation of endometrial stromal cells is mediated by ERK1-2 and AKT dependent early regulation of USF1, which directly induces Cdc2. To our knowledge, this is the first description of early target genes of progestin-activated classical PR via crosstalk with protein kinases and independently of hormone receptor binding to the genomic targets.
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Affiliation(s)
- Griselda Vallejo
- Instituto de Biología y Medicina Experimental, IByME-Conicet, Buenos Aires, Argentina
| | - Alejandro D. La Greca
- Instituto de Biología y Medicina Experimental, IByME-Conicet, Buenos Aires, Argentina
| | | | | | | | - Miguel Beato
- Centre de Regulació Genòmica, (CRG), Barcelona, Spain
- University Pompeu Fabra (UPF), Barcelona, Spain
| | - Patricia Saragüeta
- Instituto de Biología y Medicina Experimental, IByME-Conicet, Buenos Aires, Argentina
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14
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Electrochemical cell chip to detect environmental toxicants based on cell cycle arrest technique. Biosens Bioelectron 2013; 41:192-8. [DOI: 10.1016/j.bios.2012.08.023] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 08/06/2012] [Accepted: 08/08/2012] [Indexed: 01/26/2023]
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15
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Gorski JJ, Savage KI, Mulligan JM, McDade SS, Blayney JK, Ge Z, Harkin DP. Profiling of the BRCA1 transcriptome through microarray and ChIP-chip analysis. Nucleic Acids Res 2011; 39:9536-48. [PMID: 21880590 PMCID: PMC3239190 DOI: 10.1093/nar/gkr679] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Revised: 07/27/2011] [Accepted: 08/01/2011] [Indexed: 11/16/2022] Open
Abstract
A role for BRCA1 in the direct and indirect regulation of transcription is well established. However, a comprehensive view of the degree to which BRCA1 impacts transcriptional regulation on a genome-wide level has not been defined. We performed genome-wide expression profiling and ChIP-chip analysis, comparison of which revealed that although BRCA1 depletion results in transcriptional changes in 1294 genes, only 44 of these are promoter bound by BRCA1. However, 27% of these transcripts were linked to transcriptional regulation possibly explaining the large number of indirect transcriptional changes observed by microarray analysis. We show that no specific consensus sequence exists for BRCA1 DNA binding but rather demonstrate the presence of a number of known and novel transcription factor (TF)- binding sites commonly found on BRCA1 bound promoters. Co-immunoprecipitations confirmed that BRCA1 interacts with a number of these TFs including AP2-α, PAX2 and ZF5. Finally, we show that BRCA1 is bound to a subset of promoters of genes that are not altered by BRCA1 loss, but are transcriptionally regulated in a BRCA1-dependent manner upon DNA damage. These data suggest a model, whereby BRCA1 is present on defined promoters as part of an inactive complex poised to respond to various genotoxic stimuli.
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Affiliation(s)
- Julia J Gorski
- Centre for Cancer Research and Cell Biology, Queen's University Belfast, Belfast BT9 7BL and ALMAC Diagnostics, Craigavon BT63 5QD, UK.
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16
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Abstract
hsa-mir-483 is located within intron 2 of the IGF2 gene. We have previously shown oncogenic features of miR-483-3p through cooperation with IGF2 or by independently targeting the proapoptotic gene BBC3/PUMA. Here we demonstrate that expression of miR-483 can be induced independently of IGF2 by the oncoprotein β-catenin through an interaction with the basic helix-loop-helix protein upstream stimulatory transcription factor 1. We also show that β-catenin itself is a target of miR-483-3p, triggering a negative regulatory loop that becomes ineffective in cells harboring an activating mutation of β-catenin. These results provide insights into the complex regulation of the IGF2/miR-483 locus, revealing players in the β-catenin pathway.
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17
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Kafi MA, Kim TH, An JH, Choi JW. Fabrication of Cell Chip for Detection of Cell Cycle Progression Based on Electrochemical Method. Anal Chem 2011; 83:2104-11. [DOI: 10.1021/ac102895b] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Md. Abdul Kafi
- Interdisciplinary Program of Integrated Biotechnology and ‡Department of Chemical & Biomolecular Engineering, Sogang University, Shinsu-Dong, Mapo-Gu, Seoul 121-742, Republic of Korea
| | - Tae-Hyung Kim
- Interdisciplinary Program of Integrated Biotechnology and ‡Department of Chemical & Biomolecular Engineering, Sogang University, Shinsu-Dong, Mapo-Gu, Seoul 121-742, Republic of Korea
| | - Jeung Hee An
- Interdisciplinary Program of Integrated Biotechnology and ‡Department of Chemical & Biomolecular Engineering, Sogang University, Shinsu-Dong, Mapo-Gu, Seoul 121-742, Republic of Korea
| | - Jeong-Woo Choi
- Interdisciplinary Program of Integrated Biotechnology and ‡Department of Chemical & Biomolecular Engineering, Sogang University, Shinsu-Dong, Mapo-Gu, Seoul 121-742, Republic of Korea
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18
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Potapova TA, Sivakumar S, Flynn JN, Li R, Gorbsky GJ. Mitotic progression becomes irreversible in prometaphase and collapses when Wee1 and Cdc25 are inhibited. Mol Biol Cell 2011; 22:1191-206. [PMID: 21325631 PMCID: PMC3078080 DOI: 10.1091/mbc.e10-07-0599] [Citation(s) in RCA: 130] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Activation of Cdk1 is rapid and switch-like due to positive feedback mechanisms. When Cdk1 is fully on, cells are capable of M-to-G1 transition. Inhibition of positive feedback prevents rapid Cdk1 activation and induces a mitotic “collapse” phenotype characterized by the dephosphorylation of mitotic substrates without cyclin B proteolysis. Mitosis requires precise coordination of multiple global reorganizations of the nucleus and cytoplasm. Cyclin-dependent kinase 1 (Cdk1) is the primary upstream kinase that directs mitotic progression by phosphorylation of a large number of substrate proteins. Cdk1 activation reaches the peak level due to positive feedback mechanisms. By inhibiting Cdk chemically, we showed that, in prometaphase, when Cdk1 substrates approach the peak of their phosphorylation, cells become capable of proper M-to-G1 transition. We interfered with the molecular components of the Cdk1-activating feedback system through use of chemical inhibitors of Wee1 and Myt1 kinases and Cdc25 phosphatases. Inhibition of Wee1 and Myt1 at the end of the S phase led to rapid Cdk1 activation and morphologically normal mitotic entry, even in the absence of G2. Dampening Cdc25 phosphatases simultaneously with Wee1 and Myt1 inhibition prevented Cdk1/cyclin B kinase activation and full substrate phosphorylation and induced a mitotic “collapse,” a terminal state characterized by the dephosphorylation of mitotic substrates without cyclin B proteolysis. This was blocked by the PP1/PP2A phosphatase inhibitor, okadaic acid. These findings suggest that the positive feedback in Cdk activation serves to overcome the activity of Cdk-opposing phosphatases and thus sustains forward progression in mitosis.
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19
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Bae Y, Choi D, Rhim H, Kang S. Hip2 interacts with cyclin B1 and promotes its degradation through the ubiquitin proteasome pathway. FEBS Lett 2010; 584:4505-10. [DOI: 10.1016/j.febslet.2010.10.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Revised: 10/04/2010] [Accepted: 10/08/2010] [Indexed: 12/19/2022]
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20
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Galibert MD, Corre S. In vivo and in vitro tools to identify and study transcriptional regulation of USF-1 target genes. Methods Mol Biol 2010; 647:339-55. [PMID: 20694678 DOI: 10.1007/978-1-60761-738-9_21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
In response to environmental stress, cells trigger a number of molecular mechanisms to control their survival and growth. These include changes in gene expression with corresponding Post-translational modifications to critical transcriptional-control proteins. Transcription is a highly-regulated process that is impacted by a large number of ubiquitous and specific factors. In order to determine how gene expression is regulated in response to environmental cues, it is necessary to correlate modifications to specific transcription proteins with an accurate assessment of the transcriptional response. This chapter details quantitative Real Time PCR (qPCR) and Luciferase assay protocols to illustrate, both in vivo and in vitro, the role of the USF-1 transcription factor in the UV-dependant regulation of pigmentation genes (POMC and MC1R). The procedures have been optimized for the USF-1 transcription factor and the regulation of specific target genes in response to physiological UV doses.
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Affiliation(s)
- Marie-Dominique Galibert
- Genetic and Development Institute of Rennes, Transcriptional Regulation and Oncogenesis Team, Rennes University, Rennes, France.
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21
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Müller GA, Engeland K. The central role of CDE/CHR promoter elements in the regulation of cell cycle-dependent gene transcription. FEBS J 2009; 277:877-93. [PMID: 20015071 DOI: 10.1111/j.1742-4658.2009.07508.x] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The cell cycle-dependent element (CDE) and the cell cycle genes homology region (CHR) control the transcription of genes with maximum expression in G(2) phase and in mitosis. Promoters of these genes are repressed by proteins binding to CDE/CHR elements in G(0) and G(1) phases. Relief from repression begins in S phase and continues into G(2) phase and mitosis. Generally, CDE sites are located four nucleotides upstream of CHR elements in TATA-less promoters of genes such as Cdc25C, Cdc2 and cyclin A. However, expression of some other genes, such as human cyclin B1 and cyclin B2, has been shown to be controlled only by a CHR lacking a functional CDE. To date, it is not fully understood which proteins bind to and control CDE/CHR-containing promoters. Recently, components of the DREAM complex were shown to be involved in CDE/CHR-dependent transcriptional regulation. In addition, the expression of genes regulated by CDE/CHR elements is mostly achieved through CCAAT-boxes, which bind heterotrimeric NF-Y proteins as well as the histone acetyltransferase p300. Importantly, many CDE/CHR promoters are downregulated by the tumor suppressor p53. In this review, we define criteria for CDE/CHR-regulated promoters and propose to distinguish two classes of CDE/CHR-regulated genes. The regulation through transcription factors potentially binding to the CDE/CHR is discussed, and recently discovered links to central pathways regulated by E2F, the pRB family and p53 are highlighted.
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Affiliation(s)
- Gerd A Müller
- Molecular Oncology, Department of Obstetrics and Gynecology, University of Leipzig, Germany
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22
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PPARalpha ligands cause lymphocyte depletion and cell cycle block and this is associated with augmented TRB3 and reduced Cyclin B1 expression. Mol Immunol 2009; 46:3454-61. [PMID: 19748123 DOI: 10.1016/j.molimm.2009.08.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2009] [Revised: 07/18/2009] [Accepted: 08/05/2009] [Indexed: 12/14/2022]
Abstract
PPARalpha ligands are medications used clinically to prevent cardiovascular events, however studies have shown that these agents are also anti-inflammatory. Our previous studies have shown that PPARalpha ligands induce lymphocyte depletion. PPARalpha ligands also potently upregulate TRB3, a protein that has been associated with cell cycle arrest. Therefore the following studies were undertaken to determine the mechanisms associated with lymphocyte depletion. Our studies demonstrate that WY14,643, a PPARalpha ligand, decreases the amount of lymphocytes recovered after stimulation and reduces cellular divisions. Cells treated with WY14,643 also accumulate in the G2/S phase of the cell cycle. TRB3 has been shown to inhibit the phosphorylation of AKT/Protein Kinase B, and reduced activation of AKT has been associated with decreased cellular divisions and survival. However in lymphocytes, TRB3 did not reduce the phosphorylation of AKT, and WY14,643 treatment was associated with enhanced activation of AKT. Drosophila tribbles (TRB3 homolog) causes G2 arrest by decreasing the expression of a Cdc25c homolog. Lymphocytes stimulated and treated with WY14,643 have reduced expression of Cdc25c, however this is not associated with enhanced expression of phosphorylated-Cdc2 which induces G2 arrest. Instead we observed that WY14,643 consistently reduces the protein and mRNA expression of Cyclin B1. Moreover, TRB3 inhibits activation of a Cyclin B1 promoter construct. In summary, we propose that PPARalpha ligands may reduce cellular number by augmenting TRB3 expression, which in turn induces cell cycle arrest by reducing the expression of Cyclin B1. Reduced cellular divisions and cell cycle arrest may be responsible for some of the immunomodulatory effects of these agents that have been consistently observed in human trials.
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23
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Corre S, Primot A, Baron Y, Le Seyec J, Goding C, Galibert MD. Target gene specificity of USF-1 is directed via p38-mediated phosphorylation-dependent acetylation. J Biol Chem 2009; 284:18851-62. [PMID: 19389701 DOI: 10.1074/jbc.m808605200] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
How transcription factors interpret the output from signal transduction pathways to drive distinct programs of gene expression is a key issue that underpins development and disease. The ubiquitously expressed basic-helix-loop-helix leucine zipper upstream stimulating factor-1 binds E-box regulatory elements (CANNTG) to regulate a wide number of gene networks. In particular, USF-1 is a key component of the tanning process. Following UV irradiation, USF-1 is phosphorylated by the p38 stress-activated kinase on threonine 153 and directly up-regulates expression of the POMC, MC1R, TYR, TYRP-1 and DCT genes. However, how phosphorylation on Thr-153 might affect the activity of USF-1 is unclear. Here we show that, in response to DNA damage, oxidative stress and cellular infection USF-1 is acetylated in a phospho-Thr-153-dependent fashion. Phospho-acetylated USF-1 is nuclear and interacts with DNA but displays altered gene regulatory properties. Phospho-acetylated USF-1 is thus proposed to be associated with loss of transcriptional activation properties toward several target genes implicated in pigmentation process and cell cycle regulation. The identification of this critical stress-dependent USF-1 modification gives new insights into understanding USF-1 gene expression modulation associated with cancer development.
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Affiliation(s)
- Sébastien Corre
- Signaling and Development Laboratory, Marie Curie Research Institute, The Chart, Oxted RH8 OTL, United Kingdom
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24
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Wang L, Li H, Zhang Y, Santella RM, Weinstein IB. HINT1 inhibits beta-catenin/TCF4, USF2 and NFkappaB activity in human hepatoma cells. Int J Cancer 2009; 124:1526-34. [PMID: 19089909 DOI: 10.1002/ijc.24072] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In this study we explored the relevance of Hint, a novel tumor suppressor gene, to human hepatoma. The human hepatoma cell lines Hep3B and HepG2 express very low levels of the HINT1 protein but the Huh7 cells express a relatively high level. In Hep3B and HepG2 cells, but not in Huh7 cells, the promoter region of Hint1 is partially methylated and treatment with 5-azadcdeoxycytidine increased expression of the HINT1 protein and Hint1 mRNA in Hep3B and HepG2 cells. Increased expression of HINT1 in HepG2 cells markedly inhibited their growth. It also inhibited the transcriptional activities of beta-catenin/TCF4, and USF2, and inhibited the expression of endogenous cyclin D1 and TGFbeta2. Furthermore, HINT1 co-immunoprecipitated with USF2 in extracts of Hep2 cells. HINT1 also inhibited NFkappaB transcription factor reporter activity and inhibited translocation of the endogenous p65 protein to the nucleus of HepG2 cells. Therefore, decreased expression of the Hint1 gene through epigenetic silencing may play a role in enhancing the growth of a subset of human hepatoma by increasing the expression of genes controlled by the transcription factors beta-catenin, USF2, and NFkappaB.
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Affiliation(s)
- Lin Wang
- Department of Hepatobiliary Surgery, Kunming Medical College, Kunming, China
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25
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Samoylenko A, Dimova EY, Horbach T, Teplyuk N, Immenschuh S, Kietzmann T. Opposite expression of the antioxidant heme oxygenase-1 in primary cells and tumor cells: regulation by interaction of USF-2 and Fra-1. Antioxid Redox Signal 2008; 10:1163-74. [PMID: 18331200 DOI: 10.1089/ars.2007.1968] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Heme oxygenase-1 is the rate-limiting enzyme for the degradation of the prooxidant heme. Previously, we showed that an E-box within the HO-1 promoter is crucial for the regulation of HO-1 expression in primary hepatocytes. Further to investigate the importance of this E-box, we determined the regulatory capacity of the E-box-binding factor USF-2 in primary cells in comparison with transformed cell lines. We found that HO-1 expression was inhibited by USF-2 in primary cells, whereas it was induced in tumor cell lines. Mutation of either the E-box or the AP-1 site within the HO-1 promoter only partially affected the USF-dependent regulation. However, this regulation was dramatically reduced in tumor cells and completely abolished in primary cells transfected with an HO-1 promoter construct containing mutations in both the E-box and the AP-1 site, suggesting that AP-1 factors and USF-2 may act in a cooperative manner. Indeed, protein-protein interaction studies revealed that USF proteins interacted with Fra-1. Further, the USF-dependent HO-1 promoter activity was not detectable with an USF-2 mutant lacking residues of the USF-specific region (USR) or the transactivation domain encoded by exon 4. Together, these data suggest that USF-2 has opposite regulatory roles for HO-1 gene expression in primary cells and tumor cell lines.
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Affiliation(s)
- Anatoly Samoylenko
- Department of Biochemistry, University of Kaiserslautern, Kaiserslautern, Germany
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26
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Seo HR, Kim J, Bae S, Soh JW, Lee YS. Cdk5-mediated phosphorylation of c-Myc on Ser-62 is essential in transcriptional activation of cyclin B1 by cyclin G1. J Biol Chem 2008; 283:15601-10. [PMID: 18408012 PMCID: PMC2414302 DOI: 10.1074/jbc.m800987200] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2008] [Revised: 04/08/2008] [Indexed: 01/16/2023] Open
Abstract
It has been reported previously that cyclin G1 enables cells to overcome radiation-induced G(2) arrest and increased cell death and that these effects are mediated by transcriptional activation of cyclin B1. In this study, we further investigated the mechanism by which cyclin G1 transcriptionally activates cyclin B1. Deletion or point mutations within the cyclin B1 promoter region revealed that the c-Myc binding site (E-box) is necessary for cyclin G1-mediated transcriptional activation of cyclin B1 to occur. In addition, the kinase activity of Cdk5 was increased by cyclin G1 overexpression, and Cdk5 directly phosphorylated c-Myc on Ser-62. Furthermore, cyclin G1 mediated increased radiosensitivity, and radiation-induced M phase arrest was attenuated when RNA interference of Cdk5 was treated. Taken together, the results of this study indicate that Cdk5 activation in cells that overexpress cyclin G1 leads to c-Myc phosphorylation on Ser-62, which is responsible for cyclin G1-mediated transcriptional activation of cyclin B1.
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Affiliation(s)
- Haeng Ran Seo
- Division of Radiation Effect, Korea
Institute of Radiological and Medical Sciences, Seoul 139-706, Korea,
School of Life Sciences and Biotechnology, Korea
University, Seoul 136-701, Korea, and Laboratory
of Signal Transduction, Department of Chemistry, Inha University, Incheon
402-751, Korea
| | - Joon Kim
- Division of Radiation Effect, Korea
Institute of Radiological and Medical Sciences, Seoul 139-706, Korea,
School of Life Sciences and Biotechnology, Korea
University, Seoul 136-701, Korea, and Laboratory
of Signal Transduction, Department of Chemistry, Inha University, Incheon
402-751, Korea
| | - Sangwoo Bae
- Division of Radiation Effect, Korea
Institute of Radiological and Medical Sciences, Seoul 139-706, Korea,
School of Life Sciences and Biotechnology, Korea
University, Seoul 136-701, Korea, and Laboratory
of Signal Transduction, Department of Chemistry, Inha University, Incheon
402-751, Korea
| | - Jae-Won Soh
- Division of Radiation Effect, Korea
Institute of Radiological and Medical Sciences, Seoul 139-706, Korea,
School of Life Sciences and Biotechnology, Korea
University, Seoul 136-701, Korea, and Laboratory
of Signal Transduction, Department of Chemistry, Inha University, Incheon
402-751, Korea
| | - Yun-Sil Lee
- Division of Radiation Effect, Korea
Institute of Radiological and Medical Sciences, Seoul 139-706, Korea,
School of Life Sciences and Biotechnology, Korea
University, Seoul 136-701, Korea, and Laboratory
of Signal Transduction, Department of Chemistry, Inha University, Incheon
402-751, Korea
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27
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Li JP, Yang JL. Cyclin B1 proteolysis via p38 MAPK signaling participates in G2 checkpoint elicited by arsenite. J Cell Physiol 2007; 212:481-8. [PMID: 17373649 DOI: 10.1002/jcp.21042] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Timely induction of cyclin B1 controls mitotic entry, whereas its proteolysis is essential for mitotic exit. By contrast, cyclin B1 transcription is repressed during G(2) arrest induced by DNA damage. The p38 mitogen-activated protein kinase is involved in the G(2) checkpoint; yet, its impact on cyclin B1 protein levels remains unclear. Here we show that untimely proteolysis of cyclin B1 following p38 activation contributes to G(2) checkpoint. Exposing early G(2) cells to arsenite impeded cyclin B1 protein accumulation, Cdk1 activation, and G(2)-to-M progression. Conversely, cyclin B1 was non-degradable in late G(2) and mitotic cells after arsenite. Cyclin B1 proteolysis was enhanced by arsenite in early G(2) and asynchronous cells. This rapid destruction of cyclin B1 was mediated via the ubiquitin-proteasome pathway probably in a Cdc20 and Cdh1 independent mechanism. Under arsenite, inhibition of p38 activation or depletion of p38alpha suppressed cyclin B1 ubiquitination and proteolysis, while forced expression of MKK6-p38 accelerated these events. Inactivation of p38 in arsenite-treated early G(2) cells allowed G(2)-to-M progression, blocked apoptosis, increased cell viability, and decreased micronucleus formation. Thus, p38 signaling pathway triggering cyclin B1 proteolysis after arsenite may play an important role in connecting G(2) arrest with apoptosis or genome instability.
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Affiliation(s)
- Ju-Pi Li
- Molecular Carcinogenesis Laboratory, Institute of Biotechnology and Department of Life Sciences, National Tsing Hua University, Hsinchu, Taiwan
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28
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Abstract
The network of transcription factors in mast cells has not been investigated as widely as it has been in other differentiated hematopoietic cells. There are still many mechanisms of transcriptional regulation that need to be fully elucidated to understand how mast cell external stimuli lead to the appropriate physiological responses. Such information could be used to determine potential therapeutic targets for the control of mast cell activation in inflammatory diseases, allergy, and asthma. The aim of this article is to review hallmark studies in the field of transcription factor regulation in mast cells. We elaborate especially on several transcription factors studied in our laboratory in the past decade, including activator protein-1, microphthalmia-associated transcription factor, upstream stimulating factor-2, and signal transducer and activator of transcription 3.
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29
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Jung HS, Kim KS, Chung YJ, Chung HK, Min YK, Lee MS, Lee MK, Kim KW, Chung JH. USF inhibits cell proliferation through delay in G2/M phase in FRTL-5 cells. Endocr J 2007; 54:275-85. [PMID: 17379962 DOI: 10.1507/endocrj.k06-120] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Upstream stimulatory factor (USF) has a negative effect on the cell proliferation in some cell types. However, its effect on thyrocytes is not clear. Therefore, we investigated the effects of USF on the proliferation and function of thyroid follicular cells. Complementary DNAs of the USF-1 and USF-2 were synthesized using RT-PCR from FRTL-5 cells, and each was transfected to FRTL-5 cells and papillary thyroid carcinoma cell lines. Cyclic AMP (cAMP) production and [methyl-3H] thymidine uptake after thyroid stimulating hormone (TSH) treatment were measured in FRTL-5 cells. In the carcinoma cell lines, 5-bromo-2'-deoxyuridine (BrdU) uptake was assayed to evaluate cell proliferation. Apoptosis was tested by Hoechst staining and cell cycle analysis was done using a fluorescence activated cell sorting. Expression of cell cycle regulating genes was evaluated by Northern and Western blotting. Overexpression of USF-1 and USF-2 significantly suppressed TSH-stimulated [methyl-3H] thymidine uptake (p<0.05), while it maintained TSH-stimulated cAMP production in FRTL-5 cells. Overexpression of USF significantly suppressed BrdU uptake in each carcinoma cell line, NPA and TPC-1 cells (p<0.05). It induced delay of cell cycle at the G2/M phase, but did not increase apoptosis in FRTL-5 cells. It was accompanied by a decrease of cyclin B1 and cyclin-dependent kinase (CDK)-1, and an increase of p27 expression. USF-1 and USF-2 suppressed cell proliferation of normal thyrocytes and thyroid carcinoma cells. However, they retained the ability to produce cAMP after TSH stimulation. Their inhibitory effect on cell proliferation might be caused partly by the delay in G2/M phase.
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Affiliation(s)
- Hye Seung Jung
- Division of Endocrinology and Metabolism, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Korea
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Pezzolesi MG, Zbuk KM, Waite KA, Eng C. Comparative genomic and functional analyses reveal a novel cis-acting PTEN regulatory element as a highly conserved functional E-box motif deleted in Cowden syndrome. Hum Mol Genet 2007; 16:1058-71. [PMID: 17341483 DOI: 10.1093/hmg/ddm053] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Germline mutations in PTEN, encoding a phosphatase on 10q23, cause Cowden syndrome (CS) and Bannayan-Riley-Ruvalcaba syndrome (BRRS). Approximately, 10% of CS-related PTEN mutations occur in the PTEN promoter and 11% of BRRS-related mutations include large deletions, often favoring the gene's 5' end (exon 1, promoter). In order to better understand the mechanism(s) underlying the deregulation of PTEN in these syndromes, it is important that functional cis-regulatory elements be identified. We employed a comparative genomic approach combined with molecular genetic techniques to identify a highly conserved sequence upstream of the PTEN promoter, sharing 80% sequence identity among Homo sapiens, Mus musculus and Rattus norvegicus. Within this region, we identified a canonical E-box sequence (CACGTG) located at position -2181 to -2176, approximately 800 bp upstream of the PTEN core promoter and more than 1.1 kb upstream of its minimal promoter region (located at -958 to -821). In vitro assays suggest that this motif is recognized by members of the basic region-helix-loop-helix-leucine-zipper (bHLH-LZ) transcription factor family, USF1 and USF2, and reporter assays indicate that this novel E-box is involved in mediating PTEN transcriptional activation. Four of 30 CS/CS-like patients, without previously identified PTEN mutations, were found with germline deletions of the E-box element. Of the four, three had deletions stretching to exon 1, but not 3' of it; importantly, one classic CS patient harbored a germline deletion localizing to this E-box region, further affirming the role of this element in PTEN's regulation and deregulation, and its contribution to the pathogenesis of CS.
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Affiliation(s)
- Marcus G Pezzolesi
- Genomic Medicine Institute, Cleveland Clinic Foundation, 9500 Euclid Avenue, NE-50, Cleveland, OH 44195, USA
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31
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Abstract
Upstream stimulating factors, USF-1 and -2, are members of the evolutionary conserved basic-Helix-Loop-Helix-Leucine Zipper transcription factor family. The ubiquitously expressed USF-1 and -2 proteins of respectively 43 kDa and 44 kDa interact with high affinity to cognate E-box regulatory elements (CANNTG) which are particularly represented over the genome. The USF transcription factors are key regulatory elements of the transcriptional machinery mediating recruitment of chromatin remodelling enzymes, interacting with co-activators and members of the pre-initiation complex (PIC). Furthermore, transcriptionnal activity and DNA-binding of the USF proteins can be modulated by multiple ways including phosphorylation by distinct kinases (p38, protein kinase A and C, cdk1 and PI3Kinase), homo or heterodimerization formation and DNA modification of the E-box binding motif (methylation, SNP). Taken together, these parameters render very complex the understanding of the USF-dependent gene expression regulation. USF transcription factors have thus been involved as key regulators of a wide number of gene regulation network including stress and immune response, cell cycle and proliferation. This review will thus focus on general aspect of the USF transcription factors and their implications in some regulatory networks.
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Affiliation(s)
- Sébastien Corre
- CNRS UMR 6061, Laboratoire de génétique et développement, Faculté de Médecine, Université de Rennes 1, France
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Dimova EY, Kietzmann T. Cell type-dependent regulation of the hypoxia-responsive plasminogen activator inhibitor-1 gene by upstream stimulatory factor-2. J Biol Chem 2005; 281:2999-3005. [PMID: 16330554 DOI: 10.1074/jbc.m512078200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Transcriptional regulation of the plasminogen activator inhibitor type-1 (PAI-1) gene is an important issue since PAI-1 plays a crucial role in various pathological conditions. The transcription factor USF-2 was shown to be a negative regulator for rat PAI-1 expression, and therefore it was the aim of this study to evaluate the role of USF-2 for human PAI-1 expression. We found in human hepatoma cells (HepG2) that USF-2 induced human PAI-1 expression via two classical E-boxes and the hypoxia-responsive element (HRE) within the promoter. Gel-shift analyses showed that E-box 4 and E-box 5 bound USFs, and although the HRE contributed to the USF-dependent effects, it did not bind them. By contrast, USF-2 inhibited PAI-1 promoter activity in primary rat hepatocytes suggesting that PAI-1 expression depends on either the promoter context or USF activity which might be cell type-specific. Cotransfection of human or rat PAI-1 promoter luciferase constructs with expression vectors for wild-type USF-2 or USF-2 mutants in human HepG2 and rat H4IIE cells as well as in primary rat hepatocytes revealed that the effects of USF on PAI-1 expression depend on the cell type rather than the promoter context and that the USF-specific region domain of USF accounts for the observed cell type-specific effects.
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Affiliation(s)
- Elitsa Y Dimova
- Department of Biochemistry, Faculty of Chemistry, University of Kaiserslautern, D-67663 Kaiserslautern, Germany.
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Seo HR, Lee DH, Lee HJ, Baek M, Bae S, Soh JW, Lee SJ, Kim J, Lee YS. Cyclin G1 overcomes radiation-induced G2 arrest and increases cell death through transcriptional activation of cyclin B1. Cell Death Differ 2005; 13:1475-84. [PMID: 16322753 DOI: 10.1038/sj.cdd.4401822] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Although cyclin G1 has been implicated in certain p53-related biological phenomena, other aspects of its function remain unclear. Here we report hitherto unknown mechanism by which cyclin G1 increases radiation sensitivity by regulating the level of cyclin B1. Overexpression of cyclin G1 was observable in lung carcinoma tissues. Irradiation of human lung cells with cyclin G1 overexpression resulted in increased cell death and gamma-H2AX foci suggesting that cyclin G1 rendered the cells more susceptible to DNA damage. Enhanced radiosensitivity by cyclin G1 was correlated with increased cyclin B1, CDC2/cyclin B1 complex, and MPM2. Cell cycle synchronization clearly showed coexpression of cyclin G1 and cyclin B1 in G2/M phase. Depletion of cyclin G1 by interference RNA revealed that cyclin G1 regulated transcription of cyclin B1 in a p53-independent manner, and confirmed that the increased mitotic cells and cell death by cyclin G1 were dependent upon cyclin B1. Therefore, our data suggest that cyclin G1 enhanced radiation sensitivity by overriding radiation-induced G2 arrest through transcriptional upregulation of cyclin B1.
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Affiliation(s)
- H R Seo
- Laboratory of Radiation Effect, Korea Institute of Radiological and Medical Sciences, 215-4 Gongneung-Dong, Nowon-Ku, Seoul 139-706, Korea
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Corre S, Galibert MD. Upstream stimulating factors: highly versatile stress-responsive transcription factors. ACTA ACUST UNITED AC 2005; 18:337-48. [PMID: 16162174 DOI: 10.1111/j.1600-0749.2005.00262.x] [Citation(s) in RCA: 195] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Upstream stimulating factors (USF), USF-1 and USF-2, are members of the eucaryotic evolutionary conserved basic-Helix-Loop-Helix-Leucine Zipper transcription factor family. They interact with high affinity to cognate E-box regulatory elements (CANNTG), which are largely represented across the whole genome in eucaryotes. The ubiquitously expressed USF-transcription factors participate in distinct transcriptional processes, mediating recruitment of chromatin remodelling enzymes and interacting with co-activators and members of the transcription pre-initiation complex. Results obtained from both cell lines and knock-out mice indicates that USF factors are key regulators of a wide number of gene regulation networks, including the stress and immune responses, cell cycle and proliferation, lipid and glucid metabolism, and in melanocytes USF-1 has been implicated as a key UV-activated regulator of genes associated with pigmentation. This review will focus on general characteristics of the USF-transcription factors and their place in some regulatory networks.
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Affiliation(s)
- Sébastien Corre
- CNRS UMR 6061 Laboratoire de Génétique et Développement, Faculté de Médecine, Université de Rennes-1, Rennes Cedex, France
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35
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Archer SY, Johnson J, Kim HJ, Ma Q, Mou H, Daesety V, Meng S, Hodin RA. The histone deacetylase inhibitor butyrate downregulates cyclin B1 gene expression via a p21/WAF-1-dependent mechanism in human colon cancer cells. Am J Physiol Gastrointest Liver Physiol 2005; 289:G696-703. [PMID: 16160080 DOI: 10.1152/ajpgi.00575.2004] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Histone deacetylase (HDAC) inhibitors are showing promise as treatment for a variety of human cancers, but their precise mechanism of action has not been elucidated. We examined the effects of the HDAC inhibitor butyrate on colon cancer cells, focusing on its effect on the cell cycle promoter cyclin B(1). In HT-29 cells, sodium butyrate-mediated growth inhibition is associated with a marked decrease in cyclin B(1) mRNA levels. The decrease in cyclin B(1) occurred in a delayed fashion (at 24 h), is completely blocked by concomitant treatment with protein synthesis inhibitors, and appears to be dependent on changes in transcription. Cyclin B(1) repression is linked to the differentiation process in colon cancer cells, not merely with growth arrest. The mechanism of cyclin B(1) repression by butyrate requires prolonged histone hyperacetylation and is at least partly dependent on p21 expression. In fact, p21/WAF-1 appears to directly repress a minimal cyclin B(1) promoter (-90 bp), a process that can be mediated by the amino-terminal portion of the p21 protein. These findings highlight key molecular mechanisms by which HDAC inhibitors mediate their beneficial effects on human cancer cells.
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Affiliation(s)
- Sonia Y Archer
- Dept. of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
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Jiang B, Mendelson CR. O2 enhancement of human trophoblast differentiation and hCYP19 (aromatase) gene expression are mediated by proteasomal degradation of USF1 and USF2. Mol Cell Biol 2005; 25:8824-33. [PMID: 16199862 PMCID: PMC1265767 DOI: 10.1128/mcb.25.20.8824-8833.2005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2005] [Revised: 03/31/2005] [Accepted: 07/25/2005] [Indexed: 11/20/2022] Open
Abstract
When cultured in 20% O(2), human cytotrophoblasts fuse to form the syncytiotrophoblast with marked induction of hCYP19 (aromatase) gene expression. When cultured in 2% O(2), cytotrophoblast fusion and induced hCYP19 expression are prevented. These effects of hypoxia are mediated by increased expression of mammalian achaete/scute homologue-2 (Mash-2), which increases levels of upstream stimulatory factors 1 and 2 (USF1/2) and their binding as heterodimers to E-boxes surrounding the hCYP19 promoter. In studies to define mechanisms for O(2) regulation of syncytiotrophoblast differentiation, we found that hypoxia and overexpression of Mash-2 markedly increased cyclin B1 levels in cultured trophoblasts and the proportion of cells at the G(2)/M transition. Unlike USF proteins, USF1/2 mRNA levels are unaffected by O(2) tension. To determine whether increased O(2) might enhance proteasomal degradation of USF1/2, human trophoblasts were cultured in 2% or 20% O(2) with or without proteasome inhibitors. In cells cultured in 20% O(2), proteasome inhibitors increased USF1/2 protein levels and blocked spontaneous induction of hCYP19 expression, cell fusion, and differentiation. Like hypoxia, inhibitory effects of proteasome inhibitors on hCYP19 expression were mediated by increased binding of USF1/2 to the E-boxes. In human trophoblast cells cultured in 20% O(2), increased polyubiquitylation of USF1/2 proteins was observed. Thus, early in gestation when the placenta is relatively hypoxic, increased USF1/2 may block trophoblast differentiation and hCYP19 gene expression. In the second trimester, increased O(2) tension promotes proteasomal degradation of USF1/2, resulting in syncytiotrophoblast differentiation and induction of hCYP19 expression.
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Affiliation(s)
- Bing Jiang
- Departments of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, 75390, USA
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Innocente SA, Lee JM. p73 is a p53-independent, Sp1-dependent repressor of cyclin B1 transcription. Biochem Biophys Res Commun 2005; 329:713-8. [PMID: 15737644 DOI: 10.1016/j.bbrc.2005.02.028] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2005] [Indexed: 11/23/2022]
Abstract
The p53 protein family, comprised of p53, p63, and p73, has an important role in controlling cell growth and differentiation. We have previously reported that p53 prevents G(2)/M transition by decreasing intracellular levels of both cyclin B1 mRNA and protein, and attenuating the activity of the cyclin B1 promoter. The ability of p53 to control mitotic initiation by regulating intracellular cyclin B1 levels suggests that a cyclin B1-dependent G(2) checkpoint has a role in preventing neoplastic transformation. There is high sequence similarity between p73 and p53, suggesting that the two may have similar ability to repress transcription. In this report, we find that expression of p73alpha and p73beta isoforms can decrease the levels of cyclin B1 mRNA and attenuate expression from the cyclin B1 promoter. This attenuation occurs in both p53-deficient and p53-containing cell lines and cannot be inhibited by a p53 variant deficient in repressing cyclin B1 promoter activity. p73-mediated attenuation of the cyclin B1 promoter is dependent on the presence of functional Sp1-binding sites and is independent of the NF-Y-binding sites. This suggests that p73 mediates transcriptional repression through the Sp1 transcription factor.
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38
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Hock T, Nick H, Agarwal A. Upstream stimulatory factors, USF1 and USF2, bind to the human haem oxygenase-1 proximal promoter in vivo and regulate its transcription. Biochem J 2005; 383:209-18. [PMID: 15242350 PMCID: PMC1134061 DOI: 10.1042/bj20040794] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The human HO-1 (haem oxygenase-1) gene encodes a microsomal enzyme responsible for the breakdown of haem, and is also cytoprotective in response to various cellular insults. HO-1 transcription is induced by a vast array of compounds including, but certainly not limited to, haem and heavy metals such as cadmium. In the present study, we show that upstream stimulatory factors, USF1 and USF2, ubiquitous proteins belonging to the basic helix-loop-helix-leucine zipper family of transcription factors, constitutively bind to the class B E-box located in the proximal promoter of the human HO-1 gene and are responsible for the enhancement of HO-1 gene transcription in human renal proximal tubular epithelial cells. Dimethylsulphate in vivo footprinting studies have identified three protected guanine residues in the E-box of the HO-1 proximal promoter. One of these guanine contact points is essential for USF binding, and when mutated mimics a deletion mutation of the entire E-box palindrome sequence encompassing all three guanine contact points. Binding of USF1 and USF2 to the HO-1 E-box was confirmed by chromatin immunoprecipitation and gel-shift assays. Furthermore, we show that overexpression of USF1 or USF2 enhances the basal expression of HO-1 and that expression of a USF dominant negative form reduces its expression. These results demonstrate for the first time that USF proteins bind to the human HO-1 promoter in vivo and are required for high-level expression of HO-1 by haem and cadmium in human renal epithelial cells.
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Affiliation(s)
- Thomas D. Hock
- *Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, 1530 3rd Avenue South, Birmingham, AL 35294, U.S.A
| | - Harry S. Nick
- †Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL 32610, U.S.A
| | - Anupam Agarwal
- *Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, 1530 3rd Avenue South, Birmingham, AL 35294, U.S.A
- To whom correspondence should be addressed (email )
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Innocente SA, Lee JM. p53 is a NF-Y- and p21-independent, Sp1-dependent repressor of cyclin B1 transcription. FEBS Lett 2005; 579:1001-7. [PMID: 15710382 DOI: 10.1016/j.febslet.2004.12.073] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2004] [Revised: 12/17/2004] [Accepted: 12/22/2004] [Indexed: 10/25/2022]
Abstract
The p53 tumour suppressor protein is a DNA-binding transcription factor activated in response to DNA damage. Inactivation of the p53 gene occurs in 40-60% of human tumours and a substantial body of work indicates that loss of p53 activity is a critical step in oncogenesis. p53 helps to protect against neoplasia by inducing death in cells that have sustained irreparable DNA damage or by blocking cell cycle progression to allow time for DNA repair. We have previously reported that p53 prevents G2/M transition by decreasing intracellular levels of cyclin B1 protein and attenuating the activity of the cyclin B1 promoter [S.A. Innocente, J.L. Abrahamson, J.P. Cogswell, J.M. Lee, p53 regulates a G2 checkpoint through cyclin B1, Proc. Natl. Acad. Sci. USA 96 (1999) 2147-2152]. The ability of p53 to control mitotic initiation by regulating intracellular cyclin B1 levels suggests that a cyclin B1-dependent G2 checkpoint has a role in preventing neoplastic transformation. Here, we show that p53-mediated attenuation of the cyclin B1 promoter occurs in both p21+/+ and p21-/- cell lines. Furthermore, promoter attenuation is dependent on the presence of functional Sp1 binding sites and is independent of the NF-Y binding sites. We also find that wild-type, but not mutant, p53 protein binds Sp1 and the cyclin B1 promoter. This suggests that wild-type p53 mediates transcriptional repression of cyclin B1 through the Sp1 transcription factor.
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40
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Lee SR, Park JH, Park EK, Chung CH, Kang SS, Bang OS. Akt-induced promotion of cell-cycle progression at G2/M phase involves upregulation of NF-Y binding activity in PC12 cells. J Cell Physiol 2005; 205:270-7. [PMID: 15887249 DOI: 10.1002/jcp.20395] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Akt is a key downstream effector of the PI3K signaling pathway and plays a role in cell growth and survival. Expression of a myristoylated constitutively active form of Akt (myr-Akt) in PC12 cells could override cell-growth arrest at G2/M phase and apoptosis that were induced by etoposide treatment. On the other hand, inactivation of Akt by expression of its dominant negative mutant form (km-Akt) inhibited cell proliferation by arresting the cells at G2/M phase. Expression of myr-Akt also led to an increase in the protein and mRNA levels of CDK1 and cyclin B1. Furthermore, EMSA data revealed that expression of myr-Akt promoted the binding of NF-Y to the consensus CCAAT promoter sequence, whereas expression of km-Akt almost completely abolished it. Moreover, the Akt activity was minimal in the cells that were arrested at G2/M phase by nocodazole treatment, but reached to a maximal level as the cells progressed to mitosis and G1 phase upon removal of the drug. Treatment with Akt inhibitors, but not with those of MEK or p70S6K, blocked the release of the cells from the nocodazole-induced G2/M arrest, further revealing that the Akt activity is required for G2/M phase transition. These results suggest that Akt facilitate cell-cycle progression at G2/M phase in PC12 cells and this Akt activity is correlated with upregulation of NF-Y DNA-binding activity and cyclin B1/CDK1 gene expression.
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Affiliation(s)
- Sun-Ryung Lee
- Department of Biology, College of Natural Sciences, Kyungpook National University, Daegu, Korea
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41
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Corre S, Primot A, Sviderskaya E, Bennett DC, Vaulont S, Goding CR, Galibert MD. UV-induced Expression of Key Component of the Tanning Process, the POMC and MC1R Genes, Is Dependent on the p-38-activated Upstream Stimulating Factor-1 (USF-1). J Biol Chem 2004; 279:51226-33. [PMID: 15358786 DOI: 10.1074/jbc.m409768200] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Protection against UV-mediated DNA damage and the onset of oncogenesis is afforded by the tanning response in which UV irradiation triggers melanocytes to increase production of melanin that is then transferred to keratinocytes. A key component of the tanning process is the UV-mediated induction of the pro-opiomelanocortin (POMC) and MC1R genes encoding the alpha-melanocyte-stimulating hormone and its receptor, respectively, which play a crucial role in pigmentation by regulating the intracellular levels of cAMP. How these genes are regulated in response to UV irradiation is not known. Here we have shown that UV-induced activation of the POMC and MC1R promoters is mediated by p38 stress-activated kinase signaling to the transcription factor, upstream stimulating factor-1 (USF-1). Importantly, melanocytes derived from USF-1 -/- mice exhibit a defective UV response and fail to activate POMC and MC1R expression in response to UV irradiation. The results define USF-1 as a critical UV-responsive activator of genes implicated in protection from solar radiation.
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Affiliation(s)
- Sébastien Corre
- CNRS UMR 6061 Laboratoire de Génétique et Développement, Faculté de Médecine, Université de Rennes-1, 2 Avenue du Pr. Léon Bernard, 35043 Rennes, France
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42
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Chittka A, Arevalo JC, Rodriguez-Guzman M, Pérez P, Chao MV, Sendtner M. The p75NTR-interacting protein SC1 inhibits cell cycle progression by transcriptional repression of cyclin E. ACTA ACUST UNITED AC 2004; 164:985-96. [PMID: 15051733 PMCID: PMC2172053 DOI: 10.1083/jcb.200301106] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Schwann cell factor 1 (SC1), a p75 neurotrophin receptor–interacting protein, is a member of the positive regulatory/suppressor of variegation, enhancer of zeste, trithorax (PR/SET) domain-containing zinc finger protein family, and it has been shown to be regulated by serum and neurotrophins. SC1 shows a differential cytoplasmic and nuclear distribution, and its presence in the nucleus correlates strongly with the absence of bromodeoxyuridine (BrdU) in these nuclei. Here, we investigated potential transcriptional activities of SC1 and analyzed the function of its various domains. We show that SC1 acts as a transcriptional repressor when it is tethered to Gal4 DNA-binding domain. The repressive activity requires a trichostatin A–sensitive histone deacetylase (HDAC) activity, and SC1 is found in a complex with HDACs 1, 2, and 3. Transcriptional repression exerted by SC1 requires the presence of its zinc finger domains and the PR domain. Additionally, these two domains are involved in the efficient block of BrdU incorporation by SC1. The zinc finger domains are also necessary to direct SC1's nuclear localization. Lastly, SC1 represses the promoter of a promitotic gene, cyclin E, suggesting a mechanism for how growth arrest is regulated by SC1.
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Affiliation(s)
- Alexandra Chittka
- Institute for Clinical Neurobiology, University of Würzburg, Würzburg, Germany.
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43
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Martínez-Gac L, Marqués M, García Z, Campanero MR, Carrera AC. Control of cyclin G2 mRNA expression by forkhead transcription factors: novel mechanism for cell cycle control by phosphoinositide 3-kinase and forkhead. Mol Cell Biol 2004; 24:2181-9. [PMID: 14966295 PMCID: PMC350549 DOI: 10.1128/mcb.24.5.2181-2189.2004] [Citation(s) in RCA: 154] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2003] [Revised: 08/29/2003] [Accepted: 12/04/2003] [Indexed: 11/20/2022] Open
Abstract
Cyclin G2 is an unconventional cyclin highly expressed in postmitotic cells. Unlike classical cyclins that promote cell cycle progression, cyclin G2 blocks cell cycle entry. Here we studied the mechanisms that regulate cyclin G2 mRNA expression during the cell cycle. Analysis of synchronized NIH 3T3 cell cultures showed elevated cyclin G2 mRNA expression levels at G(0), with a considerable reduction as cells enter cell cycle. Downregulation of cyclin G2 mRNA levels requires activation of phosphoinositide 3-kinase, suggesting that this enzyme controls cyclin G2 mRNA expression. Because the phosphoinositide 3-kinase pathway inhibits the FoxO family of forkhead transcription factors, we examined the involvement of these factors in the regulation of cyclin G2 expression. We show that active forms of the forkhead transcription factor FoxO3a (FKHRL1) increase cyclin G2 mRNA levels. Cyclin G2 has forkhead consensus motifs in its promoter, which are transactivated by constitutive active FoxO3a forms. Finally, interference with forkhead-mediated transcription by overexpression of an inactive form decreases cyclin G2 mRNA expression levels. These results show that FoxO genes regulate cyclin G2 expression, illustrating a new role for phosphoinositide 3-kinase and FoxO transcription factors in the control of cell cycle entry.
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Affiliation(s)
- Lorena Martínez-Gac
- Department of Immunology and Oncology, Centro Nacional de Biotecnología/CSIC, Universidad Autónoma de Madrid, Cantoblanco, Madrid E-28049, Spain
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Roth U, Jungermann K, Kietzmann T. Modulation of glucokinase expression by hypoxia-inducible factor 1 and upstream stimulatory factor 2 in primary rat hepatocytes. Biol Chem 2004; 385:239-47. [PMID: 15134337 DOI: 10.1515/bc.2004.018] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Glucokinase (GK) is the key enzyme of glucose utilization in liver and is localized in the less aerobic perivenous area. Until now, the O2-responsive elements in the liver-specific GK promoter are unknown, and therefore the aim of this study was to identify the O2-responsive element in this promoter. We found that the GK promoter sequence -87/-80 matched the binding site for hypoxia inducible factor 1 (HIF-1) and upstream stimulatory factor (USF). In primary rat hepatocytes we could show that venous pO2 enhanced HIF-1alpha and USF-2a levels, both of which activated GK expression. Furthermore, transfection experiments revealed that the GK sequence -87/-80 mediated the HIF-1alpha- or USF-2-dependent activation of the GK promoter. The binding of HIF-1 and USF to the GK-HRE was corroborated by electrophoretic mobility shift assay (EMSA). However, the maximal response to HIF-1alpha or USF was only achieved when constructs with the -87/-80 sequence in context with a 3'-36 bp native GK promoter sequence containing a hepatocyte nuclear factor 4 (HNF-4) binding site were used. HIF-1alpha and HNF-4 additively activated the GK promoter, while USF-2 and HNF-4 together did not show this additive activation. Thus, HIF-1 and USF may play differential roles in the modulation of GK expression in response to O2.
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Affiliation(s)
- Ulrike Roth
- Institut für Biochemie und Molekulare Zellbiologie, Georg-August-Universität, Humboldtallee 23, D-37073 Göttingen, Germany
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45
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Chow JPH, Siu WY, Ho HTB, Ma KHT, Ho CC, Poon RYC. Differential contribution of inhibitory phosphorylation of CDC2 and CDK2 for unperturbed cell cycle control and DNA integrity checkpoints. J Biol Chem 2003; 278:40815-28. [PMID: 12912980 DOI: 10.1074/jbc.m306683200] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Inhibition of cyclin-dependent kinases (CDKs) by Thr14/Tyr15 phosphorylation is critical for normal cell cycle progression and is a converging event for several cell cycle checkpoints. In this study, we compared the relative contribution of inhibitory phosphorylation for cyclin A/B1-CDC2 and cyclin A/E-CDK2 complexes. We found that inhibitory phosphorylation plays a major role in the regulation of CDC2 but only a minor role for CDK2 during the unperturbed cell cycle of HeLa cells. The relative importance of inhibitory phosphorylation of CDC2 and CDK2 may reflect their distinct cellular functions. Despite this, expression of nonphosphorylation mutants of both CDC2 and CDK2 triggered unscheduled histone H3 phosphorylation early in the cell cycle and was cytotoxic. DNA damage by a radiomimetic drug or replication block by hydroxyurea stimulated a buildup of cyclin B1 but was accompanied by an increase of inhibitory phosphorylation of CDC2. After DNA damage and replication block, all cyclin-CDK pairs that control S phase and mitosis were to different degrees inhibited by phosphorylation. Ectopic expression of nonphosphorylated CDC2 stimulated DNA replication, histone H3 phosphorylation, and cell division even after DNA damage. Similarly, a nonphosphorylation mutant of CDK2, but not CDK4, disrupted the G2 DNA damage checkpoint. Finally, CDC25A, CDC25B, a dominant-negative CHK1, but not CDC25C or a dominant-negative WEE1, stimulated histone H3 phosphorylation after DNA damage. These data suggest differential contributions for the various regulators of Thr14/Tyr15 phosphorylation in normal cell cycle and during the DNA damage checkpoint.
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Affiliation(s)
- Jeremy P H Chow
- Department of Biochemistry, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
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46
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Szentirmay MN, Yang HX, Pawar SA, Vinson C, Sawadogo M. The IGF2 receptor is a USF2-specific target in nontumorigenic mammary epithelial cells but not in breast cancer cells. J Biol Chem 2003; 278:37231-40. [PMID: 12857727 DOI: 10.1074/jbc.m305791200] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The antiproliferative activities of the USF proteins and the frequent loss of USF function in cancer cells suggest a role for these ubiquitous transcription factors in tumor suppression. However, the cellular targets that mediate the effects of USF on cellular proliferation and transformation remain uncharacterized. IGF2R, with multiple functions in both normal growth and cancer, was investigated here as a possible USF target in both nontumorigenic and tumorigenic breast cell lines. The 5'-flanking sequences of the human IGF2R gene contain multiple, highly conserved E boxes almost identical to the consensus USF DNA-binding sequence. These E boxes were found to be essential for IGF2R promoter activity in the nontumorigenic mammary epithelial cell line MCF-10A. USF1 and USF2 bound the IGF2R promoter in vitro, and both USF1 and USF2, but not c-Myc, were present within the IGF2R promoter-associated chromatin in vivo. Overexpressed USF2, but not USF1, transactivated the IGF2R promoter, and IGF2R mRNA was markedly decreased by expression of a USF-specific dominant negative mutant, identifying IGF2R as a USF2 target. IGF2R promoter-driven expression was USF-independent in both MCF-7 and MDA-MB-231 breast cancer cell lines, suggesting that a defect in USF function may contribute to down-regulation of IGF2R expression in cancer cells.
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Affiliation(s)
- Marilyn N Szentirmay
- Department of Molecular Genetics, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA
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Laronne A, Rotkopf S, Hellman A, Gruenbaum Y, Porter ACG, Brandeis M. Synchronization of interphase events depends neither on mitosis nor on cdk1. Mol Biol Cell 2003; 14:3730-40. [PMID: 12972560 PMCID: PMC196563 DOI: 10.1091/mbc.e02-12-0850] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Human HT2-19 cells with a conditional cdk1 mutation stop dividing upon cdk1 inactivation and undergo multiple rounds of endoreplication. We show herein that major cell cycle events remain synchronized in these endoreplicating cells. DNA replication alternates with gap phases and cell cycle-specific cyclin E expression is maintained. Centrosomes duplicate in synchrony with chromosome replication, giving rise to polyploid cells with multiple centrosomes. Centrosome migration, a typical prophase event, also takes place in endoreplicating cells. The timing of these events is unaffected by cdk1 inactivation compared with normally dividing cells. Nuclear lamina breakdown, in contrast, previously shown to be dependent on cdk1, does not take place in endoreplicating HT2-19 cells. Moreover, breakdown of all other major components of the nuclear lamina, like the inner nuclear membrane proteins and nuclear pore complexes, seems also to depend on cdk1. Interestingly, the APC/C ubiquitin ligase is activated in these endoreplicating cells by fzr but not by fzy. The oscillations of interphase events are thus independent of cdk1 and of mitosis but may depend on APC/Cfzr activity.
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Affiliation(s)
- Ayelet Laronne
- Department of Genetics, Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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Gao E, Wang Y, Alcorn JL, Mendelson CR. Transcription factor USF2 is developmentally regulated in fetal lung and acts together with USF1 to induce SP-A gene expression. Am J Physiol Lung Cell Mol Physiol 2003; 284:L1027-36. [PMID: 12576297 DOI: 10.1152/ajplung.00219.2002] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Expression of the pulmonary surfactant protein A (SP-A) gene is lung specific, developmentally regulated, and enhanced by hormones and factors that increase cAMP. We previously identified two E-box-like enhancers termed distal binding element (DBE) and proximal binding element (PBE) in the 5'-flanking region of the rabbit (r) SP-A gene that are essential for cAMP induction of rSP-A promoter activity (Gao E, Alcorn JL, and Mendelson CR. J Biol Chem 268: 19697-19709, 1993). We also found that DBE and PBE serve as binding sites for the basic helix-loop-helix-leucine zipper transcription factor, upstream stimulatory factor-1 (USF1) (Gao E, Wang Y, Alcorn JL, and Mendelson CR. J Biol Chem 272: 23398-23406, 1997). In the present study, PBE was used to screen a rabbit fetal lung cDNA expression library; a cDNA insert encoding the structurally related rabbit upstream stimulatory factor-2 (rUSF2) was isolated. The levels of rUSF2 mRNA reach peak levels in fetal rabbit lung at 28 days of gestation, in concert with the time of maximal induction of SP-A gene transcription. In yeast two-hybrid analysis, rUSF2 was found to preferentially form heterodimers, compared with homodimers, with rUSF1. Binding complexes of nuclear proteins isolated from fetal rabbit lung type II cells with the DBE and PBE were supershifted by anti-rUSF2 antibodies. Binding activity was enriched in nuclear proteins from type II cells compared with fibroblasts. Overexpression of rUSF2 in transfected lung A549 cells increased rSP-A promoter activity and acted synergistically with rUSF1. We suggest that heterodimers of USF2 and USF1 bound to two E-box elements in the SP-A gene 5'-flanking region serve a key role in developmental and hormonal regulation of SP-A gene expression in pulmonary type II cells.
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Affiliation(s)
- Erwei Gao
- Departments of Biochemistry and Obstetrics and Gynecology, The University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390-9038, USA.
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Abstract
Life on earth has evolved on a photic carousel, spinning through alternating periods of light and darkness. This playful image belies the fact that only those organisms that learned how to benefit from the recurring features in their environment were allowed to ride on. This selection process has engendered many daily rhythms in our biosphere, most of which rely on the anticipatory power of an endogenously generated marker of phase: the biological clock. The basic mechanisms driving this remarkable device have been really tough to decode but are finally beginning to unravel as chronobiologists probe deeper and wider in and around the recently discovered gears of the clock. Like its chemical predecessors, biological circadian oscillators are characterized by interlaced positive and negative feedback loops, but with constants and variables carefully balanced to achieve an approximately 24h period. The loops at the heart of these biological oscillators are sustained by specific patterns of gene expression and precisely tuned posttranscriptional modifications. It follows that a molecular understanding of the biological clock hinges, in no small measure, on a better understanding of the cis-acting elements that bestow a given gene with its circadian properties. The present review summarizes what is known about these elements and what remains to be elucidated.
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Affiliation(s)
- Estela Muñoz
- Unit on Temporal Gene Expression, Laboratory of Cellular and Molecular Regulation, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, USA
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50
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Wasner M, Tschöp K, Spiesbach K, Haugwitz U, Johne C, Mössner J, Mantovani R, Engeland K. Cyclin B1 transcription is enhanced by the p300 coactivator and regulated during the cell cycle by a CHR-dependent repression mechanism. FEBS Lett 2003; 536:66-70. [PMID: 12586340 DOI: 10.1016/s0014-5793(03)00028-0] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Cyclin B is a central regulator of transition from the G(2) phase of the cell cycle to mitosis. In mammalian cells two B-type cyclins have been characterised, cyclin B1 and B2. Both are expressed with a maximum in G(2) and their synthesis is mainly regulated on the transcriptional level. We show that a single cell cycle genes homology region, lacking a functional cell cycle-dependent element in tandem with it, contributes most of the cell cycle-dependent transcription from the cyclin B1 promoter. The coactivator p300 binds to the cyclin B1 promoter and synergises with the transcription factor NF-Y in activating transcription of cyclin B1.
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Affiliation(s)
- Mark Wasner
- Medizinische Klinik und Poliklinik II, Max-Bürger-Forschungszentrum, Universität Leipzig, Johannisallee 30, D-04103 Leipzig, Germany
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