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Chi TF, Horbach T, Götz C, Kietzmann T, Dimova EY. Cyclin-Dependent Kinase 5 (CDK5)-Mediated Phosphorylation of Upstream Stimulatory Factor 2 (USF2) Contributes to Carcinogenesis. Cancers (Basel) 2019; 11:cancers11040523. [PMID: 31013770 PMCID: PMC6521020 DOI: 10.3390/cancers11040523] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2019] [Revised: 03/30/2019] [Accepted: 04/08/2019] [Indexed: 12/12/2022] Open
Abstract
The transcription factor USF2 is supposed to have an important role in tumor development. However, the regulatory mechanisms contributing to the function of USF2 are largely unknown. Cyclin-dependent kinase 5 (CDK5) seems to be of importance since high levels of CDK5 were found in different cancers associated with high USF2 expression. Here, we identified USF2 as a phosphorylation target of CDK5. USF2 is phosphorylated by CDK5 at two serine residues, serine 155 and serine 222. Further, phosphorylation of USF2 at these residues was shown to stabilize the protein and to regulate cellular growth and migration. Altogether, these results delineate the importance of the CDK5-USF2 interplay in cancer cells.
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Affiliation(s)
- Tabughang Franklin Chi
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, 90014 Oulu, Finland; (T.F.C.); (T.K.)
| | - Tina Horbach
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, 90014 Oulu, Finland; (T.F.C.); (T.K.)
| | - Claudia Götz
- Medical Biochemistry and Molecular Biology, Saarland University, 66421 Homburg, Germany;
| | - Thomas Kietzmann
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, 90014 Oulu, Finland; (T.F.C.); (T.K.)
| | - Elitsa Y. Dimova
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, 90014 Oulu, Finland; (T.F.C.); (T.K.)
- Correspondence: ; Tel.: +358-0-294-485-785; Fax: +358-8-553-114
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2
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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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3
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Functional interplay between the transcription factors USF1 and PDX-1 and protein kinase CK2 in pancreatic β-cells. Sci Rep 2017; 7:16367. [PMID: 29180680 PMCID: PMC5703852 DOI: 10.1038/s41598-017-16590-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 10/04/2017] [Indexed: 11/22/2022] Open
Abstract
Glucose homeostasis is regulated by insulin, which is produced in the β-cells of the pancreas. The synthesis of insulin is controlled by several transcription factors including PDX-1, USF1 and USF2. Both, PDX-1 and USF1 were identified as substrates for protein kinase CK2. Here, we have analysed the interplay of PDX-1, USF1 and CK2 in the regulation of PDX-1 gene transcription. We found that the PDX-1 promoter is dose-dependently transactivated by PDX-1 and transrepressed by USF1. With increasing glucose concentrations the transrepression of the PDX-1 promoter by USF1 is successively abrogated. PDX-1 binding to its own promoter was not influenced by glucose, whereas USF1 binding to the PDX-1 promoter was reduced. The same effect was observed after inhibition of the protein kinase activity by three different inhibitors or by using a phospho-mutant of USF1. Moreover, phosphorylation of USF1 by CK2 seems to strengthen the interaction between USF1 and PDX-1. Thus, CK2 is a negative regulator of the USF1-dependent PDX-1 transcription. Moreover, upon inhibition of CK2 in primary islets, insulin expression as well as insulin secretion were enhanced without affecting the viability of the cells. Therefore, inhibition of CK2 activity may be a promising approach to stimulate insulin production in pancreatic β-cells.
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Wang Y, Viscarra J, Kim SJ, Sul HS. Transcriptional regulation of hepatic lipogenesis. Nat Rev Mol Cell Biol 2016; 16:678-89. [PMID: 26490400 DOI: 10.1038/nrm4074] [Citation(s) in RCA: 453] [Impact Index Per Article: 56.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Fatty acid and fat synthesis in the liver is a highly regulated metabolic pathway that is important for very low-density lipoprotein (VLDL) production and thus energy distribution to other tissues. Having common features at their promoter regions, lipogenic genes are coordinately regulated at the transcriptional level. Transcription factors, such as upstream stimulatory factors (USFs), sterol regulatory element-binding protein 1C (SREBP1C), liver X receptors (LXRs) and carbohydrate-responsive element-binding protein (ChREBP) have crucial roles in this process. Recently, insights have been gained into the signalling pathways that regulate these transcription factors. After feeding, high blood glucose and insulin levels activate lipogenic genes through several pathways, including the DNA-dependent protein kinase (DNA-PK), atypical protein kinase C (aPKC) and AKT-mTOR pathways. These pathways control the post-translational modifications of transcription factors and co-regulators, such as phosphorylation, acetylation or ubiquitylation, that affect their function, stability and/or localization. Dysregulation of lipogenesis can contribute to hepatosteatosis, which is associated with obesity and insulin resistance.
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Affiliation(s)
- Yuhui Wang
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, California 94720, USA
| | - Jose Viscarra
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, California 94720, USA
| | - Sun-Joong Kim
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, California 94720, USA
| | - Hei Sook Sul
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, California 94720, USA
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5
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Yamanaka T, Tosaki A, Kurosawa M, Shimogori T, Hattori N, Nukina N. Genome-wide analyses in neuronal cells reveal that upstream transcription factors regulate lysosomal gene expression. FEBS J 2016; 283:1077-87. [DOI: 10.1111/febs.13650] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 12/17/2015] [Accepted: 01/08/2016] [Indexed: 12/01/2022]
Affiliation(s)
- Tomoyuki Yamanaka
- Laboratory of Structural Neuropathology; Doshisha University Graduate School of Brain Science; Kyoto Japan
- Laboratory for Structural Neuropathology; RIKEN Brain Science Institute; Saitama Japan
- Department of Neuroscience for Neurodegenerative Disorders; Juntendo University Graduate School of Medicine; Tokyo Japan
- Laboratory for Molecular Mechanisms of Thalamus Development; RIKEN Brain Science Institute; Saitama Japan
| | - Asako Tosaki
- Laboratory for Structural Neuropathology; RIKEN Brain Science Institute; Saitama Japan
| | - Masaru Kurosawa
- Laboratory for Structural Neuropathology; RIKEN Brain Science Institute; Saitama Japan
- Department of Neuroscience for Neurodegenerative Disorders; Juntendo University Graduate School of Medicine; Tokyo Japan
| | - Tomomi Shimogori
- Laboratory for Molecular Mechanisms of Thalamus Development; RIKEN Brain Science Institute; Saitama Japan
| | - Nobutaka Hattori
- Department of Neurology; Juntendo University Graduate School of Medicine; Tokyo Japan
| | - Nobuyuki Nukina
- Laboratory of Structural Neuropathology; Doshisha University Graduate School of Brain Science; Kyoto Japan
- Laboratory for Structural Neuropathology; RIKEN Brain Science Institute; Saitama Japan
- Department of Neuroscience for Neurodegenerative Disorders; Juntendo University Graduate School of Medicine; Tokyo Japan
- Laboratory for Molecular Mechanisms of Thalamus Development; RIKEN Brain Science Institute; Saitama Japan
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6
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Abstract
Diabetic nephropathy (DN) is the most common cause of end-stage renal disease (ESRD). About 20%-30% of people with type 1 and type 2 diabetes develop DN. DN is characterized by both glomerulosclerosis with thickening of the glomerular basement membrane and mesangial matrix expansion, and tubulointerstitial fibrosis. Hyperglycemia and the activation of the intra-renal renin-angiotensin system (RAS) in diabetes have been suggested to play a critical role in the pathogenesis of DN. However, the mechanisms are not well known. Studies from our laboratory demonstrated that the transcription factor-upstream stimulatory factor 2 (USF2) is an important regulator of DN. Moreover, the renin gene is a downstream target of USF2. Importantly, USF2 transgenic (Tg) mice demonstrate a specific increase in renal renin expression and angiotensin II (AngII) levels in kidney and exhibit increased urinary albumin excretion and extracellular matrix deposition in glomeruli, supporting a role for USF2 in the development of diabetic nephropathy. In this review, we summarize our findings of the mechanisms by which diabetes regulates USF2 in kidney cells and its role in regulation of renal renin-angiotensin system and the development of diabetic nephropathy.
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Affiliation(s)
- Shuxia Wang
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, KY 40536, USA
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7
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Horbach T, Götz C, Kietzmann T, Dimova EY. Protein kinases as switches for the function of upstream stimulatory factors: implications for tissue injury and cancer. Front Pharmacol 2015; 6:3. [PMID: 25741280 PMCID: PMC4332324 DOI: 10.3389/fphar.2015.00003] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 01/07/2015] [Indexed: 01/30/2023] Open
Abstract
The upstream stimulatory factors (USFs) are regulators of important cellular processes. Both USF1 and USF2 are supposed to have major roles in metabolism, tissue protection and tumor development. However, the knowledge about the mechanisms that control the function of USFs, in particular in tissue protection and cancer, is limited. Phosphorylation is a versatile tool to regulate protein functions. Thereby, phosphorylation can positively or negatively affect different aspects of transcription factor function including protein stability, protein-protein interaction, cellular localization, or DNA binding. The present review aims to summarize the current knowledge about the regulation of USFs by direct phosphorylation and the consequences for USF functions in tissue protection and cancer.
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Affiliation(s)
- Tina Horbach
- Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu , Oulu, Finland ; Department of Chemistry, University of Kaiserslautern , Kaiserslautern, Germany
| | - Claudia Götz
- Medical Biochemistry and Molecular Biology, Saarland University , Homburg, Germany
| | - Thomas Kietzmann
- Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu , Oulu, Finland
| | - Elitsa Y Dimova
- Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu , Oulu, Finland
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8
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Ameri K, Jahangiri A, Rajah AM, Tormos KV, Nagarajan R, Pekmezci M, Nguyen V, Wheeler ML, Murphy MP, Sanders TA, Jeffrey SS, Yeghiazarians Y, Rinaudo PF, Costello JF, Aghi MK, Maltepe E. HIGD1A Regulates Oxygen Consumption, ROS Production, and AMPK Activity during Glucose Deprivation to Modulate Cell Survival and Tumor Growth. Cell Rep 2015; 10:891-899. [PMID: 25683712 DOI: 10.1016/j.celrep.2015.01.020] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 10/27/2014] [Accepted: 01/09/2015] [Indexed: 02/07/2023] Open
Abstract
Hypoxia-inducible gene domain family member 1A (HIGD1A) is a survival factor induced by hypoxia-inducible factor 1 (HIF-1). HIF-1 regulates many responses to oxygen deprivation, but viable cells within hypoxic perinecrotic solid tumor regions frequently lack HIF-1α. HIGD1A is induced in these HIF-deficient extreme environments and interacts with the mitochondrial electron transport chain to repress oxygen consumption, enhance AMPK activity, and lower cellular ROS levels. Importantly, HIGD1A decreases tumor growth but promotes tumor cell survival in vivo. The human Higd1a gene is located on chromosome 3p22.1, where many tumor suppressor genes reside. Consistent with this, the Higd1a gene promoter is differentially methylated in human cancers, preventing its hypoxic induction. However, when hypoxic tumor cells are confronted with glucose deprivation, DNA methyltransferase activity is inhibited, enabling HIGD1A expression, metabolic adaptation, and possible dormancy induction. Our findings therefore reveal important new roles for this family of mitochondrial proteins in cancer biology.
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Affiliation(s)
- Kurosh Ameri
- Department of Pediatrics/Biomedical Sciences, University of California San Francisco, San Francisco, CA 94143, USA
| | - Arman Jahangiri
- Department of Neurological Surgery, University of California San Francisco, San Francisco, CA 94143, USA
| | - Anthony M Rajah
- Department of Pediatrics/Biomedical Sciences, University of California San Francisco, San Francisco, CA 94143, USA
| | - Kathryn V Tormos
- Department of Pediatrics/Biomedical Sciences, University of California San Francisco, San Francisco, CA 94143, USA
| | - Ravi Nagarajan
- Department of Neurological Surgery, University of California San Francisco, San Francisco, CA 94143, USA
| | - Melike Pekmezci
- Department of Pathology, University of California San Francisco, San Francisco, CA 94143, USA
| | - Vien Nguyen
- Department of Biomedical Sciences, University of California San Francisco, San Francisco, CA 94143, USA
| | - Matthew L Wheeler
- Department of Microbiology/Immunology, University of California San Francisco, San Francisco, CA 94143, USA
| | | | - Timothy A Sanders
- Department of Pediatrics/Biomedical Sciences, University of California San Francisco, San Francisco, CA 94143, USA
| | - Stefanie S Jeffrey
- Department of Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Yerem Yeghiazarians
- Department of Medicine/CVRI/Eli and Edythe Broad Center for Regeneration Medicine, University of California San Francisco, San Francisco, CA 94143, USA
| | - Paolo F Rinaudo
- Department of Obstetrics, Gynecology/Reproductive Sciences, University of California San Francisco, San Francisco, CA 94143, USA
| | - Joseph F Costello
- Department of Neurological Surgery, University of California San Francisco, San Francisco, CA 94143, USA
| | - Manish K Aghi
- Department of Neurological Surgery, University of California San Francisco, San Francisco, CA 94143, USA
| | - Emin Maltepe
- Department of Pediatrics/Biomedical Sciences, University of California San Francisco, San Francisco, CA 94143, USA.
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9
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Zeng C, Wang J, Li N, Shen M, Wang D, Yu Q, Wang H. AKAP150 mobilizes cPKC-dependent cardiac glucotoxicity. Am J Physiol Endocrinol Metab 2014; 307:E384-97. [PMID: 25005497 DOI: 10.1152/ajpendo.00175.2014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Activation of conventional PKCs (cPKC) is a key signaling that directs the cardiac toxicity of hyperglycemia. AKAP150, a scaffold protein of the A-kinase anchoring proteins (AKAPs) family, is less defined regarding its capability to anchor and regulate cardiac cPKC signaling. This study was designed to investigate the role of AKAP150 in cPKC-mediated cardiac glucotoxicity. In cardiac tissues from streptozotocin-induced diabetic rats and high-glucose-treated neonatal rat cardiomyocytes, both mRNA and protein levels of AKAP150 increased significantly, and marked elevations were observed in cPKC activity and both expression and phosphorylation levels of p65 NF-κB and p47(phox). AKAP150 knockdown was established via intramyocardial injection in vivo and transfection in vitro of adenovirus carrying AKAP150-targeted shRNA. Downregulation of AKAP150 reversed diabetes-induced diastolic dysfunction as manifested by decreased left ventricular end-diastolic diameter and early/late mitral diastolic wave ratio. AKAP150 inhibition also abrogated high-glucose-induced cardiomyocyte apoptosis (TUNEL staining and annexin V/propidium iodide flow cytometry) and oxidative stress (ROS production, NADPH oxidase activity, and lipid peroxidation). More importantly, reduced AKAP150 expression significantly inhibited high-glucose-induced membrane translocation and activation of cPKC and suppressed the increases in the phosphorylation of p65 NF-κB and p47(phox). Immunofluorescent coexpression and immunoprecipitation indicated enhanced anchoring of AKAP150 with cPKC within the plasma membrane under hyperglycemia, and AKAP150 preferentially colocalized and functionally bound with PKCα and -β isoforms. These results suggest that cardiac AKAP150 positively responds to hyperglycemia and enhances the efficiency of glucotoxicity signaling through a cPKC/p47(phox)/ROS pathway that induces myocardial dysfunction, cardiomyocyte apoptosis, and oxidative stress.
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Affiliation(s)
- Chao Zeng
- Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Xi'an, China; and
| | - Jinyi Wang
- Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Xi'an, China; and
| | - Na Li
- Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Xi'an, China; and
| | - Mingzhi Shen
- Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Xi'an, China; and Department of Cardiology, Hainan Branch of the PLA General Hospital, Sanya, China
| | - Dongjuan Wang
- Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Xi'an, China; and
| | - Qiujun Yu
- Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Xi'an, China; and
| | - Haichang Wang
- Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Xi'an, China; and
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10
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Matsuda M, Tamura K, Wakui H, Maeda A, Ohsawa M, Kanaoka T, Azushima K, Uneda K, Haku S, Tsurumi-Ikeya Y, Toya Y, Maeshima Y, Yamashita A, Umemura S. Upstream stimulatory factors 1 and 2 mediate the transcription of angiotensin II binding and inhibitory protein. J Biol Chem 2013; 288:19238-49. [PMID: 23653383 PMCID: PMC3696694 DOI: 10.1074/jbc.m113.451054] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The angiotensin II type 1 receptor (AT1R)-associated protein (ATRAP/Agtrap) promotes constitutive internalization of the AT1R so as to specifically inhibit the pathological activation of its downstream signaling yet preserve the base-line physiological signaling activity of the AT1R. Thus, tissue-specific regulation of Agtrap expression is relevant to the pathophysiology of cardiovascular and renal disease. However, the regulatory mechanism of Agtrap gene expression has not yet been fully elucidated. In this study, we show that the proximal promoter region from −150 to +72 of the mouse Agtrap promoter, which contains the X-box, E-box, and GC-box consensus motifs, is able to elicit substantial transcription of the Agtrap gene. Among these binding motifs, we showed that the E-box specifically binds upstream stimulatory factor (Usf) 1 and Usf2, which are known E-box-binding transcription factors. It is indicated that the E-box-Usf1/Usf2 binding regulates Agtrap expression because of the following: 1) mutation of the E-box to prevent Usf1/Usf2 binding reduces Agtrap promoter activity; 2) knockdown of Usf1 or Usf2 affects both endogenous Agtrap mRNA and Agtrap protein expression, and 3) the decrease in Agtrap mRNA expression in the afflicted kidney by unilateral ureteral obstruction is accompanied by changes in Usf1 and Usf2 mRNA. Furthermore, the results of siRNA transfection in mouse distal convoluted tubule cells and those of unilateral ureteral obstruction in the afflicted mouse kidney suggest that Usf1 decreases but Usf2 increases the Agtrap gene expression by binding to the E-box. The results also demonstrate a functional E-box-USF1/USF2 interaction in the human AGTRAP promoter, thereby suggesting that a strategy of modulating the E-box-USF1/USF2 binding has novel therapeutic potential.
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Affiliation(s)
- Miyuki Matsuda
- Department of Medical Science and Cardiorenal Medicine, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, USA
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11
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Park S, Liu X, Davis DR, Sigmund CD. Gene trapping uncovers sex-specific mechanisms for upstream stimulatory factors 1 and 2 in angiotensinogen expression. Hypertension 2012; 59:1212-9. [PMID: 22547438 DOI: 10.1161/hypertensionaha.112.192971] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
A single-nucleotide polymorphism (C/A) located within an E-box at the -20 position of the human angiotensinogen (AGT) promoter may regulate transcriptional activation through differential recruitment of the transcription factors upstream stimulatory factor (USF) 1 and 2. To study the contribution of USF1 on AGT gene expression, mice carrying a (-20C) human AGT (hAGT) transgene were bred with mice harboring a USF1 gene trap allele designed to knock down USF1 expression. USF1 mRNA was reduced relative to controls in liver (9 ± 1%), perigenital adipose (16 ± 3%), kidney (17 ± 1%), and brain (34 ± 2%) in double-transgenic mice. This decrease was confirmed by electrophoretic mobility shift assay. Chromatin immunoprecipitation analyses revealed a decrease in USF1, with retention of USF2 binding at the hAGT promoter in the liver of male mice. hAGT expression was reduced in the liver and other tissues of female but not male mice. The decrease in endogenous AGT expression was insufficient to alter systolic blood pressure at baseline but caused reduced systolic blood pressure in female USF1 gene trap mice fed a high-fat diet. Treatment of USF1 knockdown males with intravenous adenoviral short hairpin RNA targeting USF2 resulted in reduced expression of USF1, USF2, and hAGT protein. Our data from chromatin immunoprecipitation assays suggests that this decrease in hAGT is attributed to decreased USF2 binding to the hAGT promoter. In conclusion, both USF1 and USF2 are essential for AGT transcriptional regulation, and distinct sex-specific and tissue-specific mechanisms are involved in the activities of these transcription factors in vivo.
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Affiliation(s)
- Sungmi Park
- Department of Pharmacology, 3181 MERF, Roy J and Lucille A Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
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12
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Sanchez AP, Zhao J, You Y, Declèves AE, Diamond-Stanic M, Sharma K. Role of the USF1 transcription factor in diabetic kidney disease. Am J Physiol Renal Physiol 2011; 301:F271-9. [PMID: 21543418 PMCID: PMC3154594 DOI: 10.1152/ajprenal.00221.2011] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2011] [Accepted: 04/28/2011] [Indexed: 01/07/2023] Open
Abstract
The predominant transcription factors regulating key genes in diabetic kidney disease have not been established. The transcription factor upstream stimulatory factor 1 (USF1) is an important regulator of glucose-mediated transforming growth factor (TGF)-β1 expression in mesangial cells; however, its role in the development of diabetic kidney disease has not been evaluated. In the present study, wild-type (WT; USF1 +/+), heterozygous (USF1 +/-), and homozygous (USF1 -/-) knockout mice were intercrossed with Akita mice (Ins2/Akita) to induce type 1 diabetes. Mice were studied up to 36 wk of age. The degree of hyperglycemia and kidney hypertrophy were similar in all groups of diabetic mice; however, the USF1 -/- diabetic mice had significantly less albuminuria and mesangial matrix expansion than the WT diabetic mice. TGF-β1 and renin gene expression and protein were substantially increased in the WT diabetic mice but not in USF1 -/- diabetic mice. The underlying pathway by which USF1 is regulated by high glucose was investigated in mesangial cell culture. High glucose inhibited AMP-activated protein kinase (AMPK) activity and increased USF1 nuclear translocation. Activation of AMPK with AICAR stimulated AMPK activity and reduced nuclear accumulation of USF1. We thus conclude that USF1 is a critical transcription factor regulating diabetic kidney disease and plays a critical role in albuminuria, mesangial matrix accumulation, and TGF-β1 and renin stimulation in diabetic kidney disease. AMPK activity may play a key role in high glucose-induced regulation of USF1.
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Affiliation(s)
- Amber P Sanchez
- Center for Renal Translational Medicine, Division of Nephrology-Hypertension, Department of Medicine, University of California, Veterans Administration San Diego HealthCare System, La Jolla, 92093, USA
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13
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Abstract
Hepcidin, the Fe-regulatory peptide, has been shown to inhibit Fe absorption and reticuloendothelial Fe recycling. The present study was conducted to explore the mechanism of in vivo Fe regulation through genetic disruption of hepcidin1 and acute effects of hepcidin treatment in hepcidin1 knockout (Hepc1-/-) and heterozygous mice. Hepcidin1 disruption resulted in significantly increased intestinal Fe uptake. Hepcidin injection inhibited Fe absorption in both genotypes, but the effects were more evident in the knockout mice. Hepcidin administration was also associated with decreased membrane localisation of ferroportin in the duodenum, liver and, most significantly, in the spleen of Hepc1-/- mice. Hypoferraemia was induced in heterozygous mice by hepcidin treatment, but not in Hepc1-/- mice, 4 h after injection. Interestingly, Fe absorption and serum Fe levels in Hepc1-/- and heterozygous mice fed a low-Fe diet were not affected by hepcidin injection. The present study demonstrates that hepcidin deficiency causes increased Fe absorption. The effects of hepcidin were abolished by dietary Fe deficiency, indicating that the response to hepcidin may be influenced by dietary Fe level or Fe status.
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14
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Li Y, Wang S. Glycated albumin upregulates upstream stimulatory factor 2 gene transcription in mesangial cells. Am J Physiol Renal Physiol 2010; 299:F121-7. [PMID: 20410211 DOI: 10.1152/ajprenal.00074.2010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Diabetic nephropathy (DN) is the most common cause of end-stage renal failure. We previously demonstrated that a transcription factor called upstream stimulatory factor 2 (USF2) was upregulated in the kidneys from diabetic animals in vivo as well as in mesangial cells (MCs) exposed to high-glucose media in vitro. USF2 mediates glucose-induced thrombospondin 1 expression and transforming growth factor-beta activity in MCs and plays a role in DN. Glycated proteins have been shown to accumulate in the kidneys of diabetic patients and contribute to DN. However, whether glycated proteins regulate USF2 expression in MCs and play a role in DN is unknown. In the present studies, we determined the effect of glycated albumin on UFS2 gene expression in primary rat MCs. We found that glycated albumin upregulated USF2 expression (mRNA and protein) in a dose- and time-dependent manner. We also demonstrated that glycated albumin stimulated USF2 gene expression at the transcriptional level. By using the luciferase-promoter deletion assay, site-directed mutagenesis, and transactivation assay, we identified a glycated albumin-responsive region in the USF2 gene promoter (-837 to -430, relative to the transcription start site) and demonstrated that glycated albumin-induced USF2 expression was mediated through NF-kappaB-dependent transactivation of the USF2 promoter. Furthermore, glycated albumin increased nuclear NF-kappaB subunit-p65 protein levels. siRNA-mediated p65 knockdown prevented glycated albumin-induced USF2 gene expression (promoter activity, mRNA, and protein levels). Taken together, these data suggest that glycated albumin upregulated USF2 gene transcription in MCs through NF-kappaB-dependent transactivation of the USF2 promoter.
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Affiliation(s)
- Yanzhang Li
- Graduate Center for Nutritional Sciences, University of Kentucky, Lexington, Kentucky 40536, USA
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Abstract
Approximately a third of patients with diabetes develop diabetic kidney disease, and diabetes is the leading cause of end-stage renal disease in most developed countries. Hyperglycaemia is known to activate genes that ultimately lead to extracellular matrix accumulation, the hallmark of diabetic nephropathy. Several transcription factors have been implicated in glucose-mediated expression of genes involved in diabetic nephropathy. This review focuses on the transcription factors upstream stimulatory factors 1 and 2 (USF1 and 2), activator protein 1 (AP-1), nuclear factor (NF)-kappaB, cAMP-response-element-binding protein (CREB), nuclear factor of activated T cells (NFAT), and stimulating protein 1 (Sp1). In response to high glucose, several of these transcription factors regulate the gene encoding the profibrotic cytokine transforming growth factor beta, as well as genes for a range of other proteins implicated in inflammation and extracellular matrix turnover, including thrombospondin 1, the chemokine CCL2, osteopontin, fibronectin, decorin, plasminogen activator inhibitor 1 and aldose reductase. Identifying the molecular mechanisms by which diabetic nephropathy occurs has important clinical implications as therapies can then be tailored to target those at risk. Strategies to specifically target transcription factor activation and function may be employed to halt the progression of diabetic nephropathy.
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Shi L, Nikolic D, Liu S, Lu H, Wang S. Activation of renal renin-angiotensin system in upstream stimulatory factor 2 transgenic mice. Am J Physiol Renal Physiol 2008; 296:F257-65. [PMID: 19004931 DOI: 10.1152/ajprenal.90493.2008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Previously we demonstrated that upstream stimulatory factor 2 (USF2) transgenic (Tg) mice developed nephropathy including albuminuria and glomerular hypertrophy, accompanied by increased transforming growth factor (TGF)-beta and fibronectin accumulation in the glomeruli. However, the mechanisms by which overexpression of USF2 induces kidney injury are unknown. USF has been shown to regulate renin expression. Moreover, the renin-angiotensin system (RAS) plays important roles in renal diseases. Therefore, in the present studies the effects of USF2 on the regulation of RAS in the kidney as well as in mesangial cells from USF2 (Tg) mice were examined. The role of USF2-mediated regulation of RAS in TGF-beta production in mesangial cells was also determined. Our data demonstrate that USF2 (Tg) mice exhibit increased renin and angiotensin (ANG) II levels in the kidney. In contrast, renal expression of other components of RAS such as renin receptor, angiotensinogen, angiotensin-converting enzyme (ACE), ACE2, angiotensin type 1a (AT(1a)) receptor, and AT(2) receptor was not altered in USF2 (Tg) mice. Similarly, mesangial cells isolated from USF2 (Tg) mice had increased renin and ANG II levels. Mesangial cells overexpressing USF2 also had increased TGF-beta production, which was blocked by small interfering RNA-mediated renin gene knockdown or RAS blockade (enalapril or losartan). Collectively, these results suggest that USF2 promotes renal renin expression and stimulates ANG II generation, leading to activation of the intrarenal RAS. In addition, renin-dependent ANG II generation mediates the effect of USF2 on TGF-beta production in mesangial cells, which may contribute to the development of nephropathy in USF2 (Tg) mice.
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Affiliation(s)
- Lihua Shi
- Graduate Center for Nutritional Sciences, Univ. of Kentucky, Wethington Bldg. Rm. 517, 900 S. Limestone St., Lexington, KY 40536-0200, USA
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17
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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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18
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Glucose Regulates the Expression of the Apolipoprotein A5 Gene. J Mol Biol 2008; 380:789-98. [DOI: 10.1016/j.jmb.2008.04.057] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2007] [Revised: 04/22/2008] [Accepted: 04/23/2008] [Indexed: 11/23/2022]
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Shi L, Liu S, Nikolic D, Wang S. High glucose levels upregulate upstream stimulatory factor 2 gene transcription in mesangial cells. J Cell Biochem 2008; 103:1952-1961. [PMID: 17955499 PMCID: PMC9084927 DOI: 10.1002/jcb.21585] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
Abstract
Previously, we demonstrated that upstream stimulatory factor 2 (USF2) mediates high glucose-induced thrombospondin1 (TSP1) gene expression and TGF-beta activity in glomerular mesangial cells and plays a role in diabetic renal complications. In the present studies, we further determined the molecular mechanisms by which high glucose levels regulate USF2 gene expression. In primary rat mesangial cells, we found that glucose treatment time and dose-dependently up-regulated USF2 expression (mRNA and protein). By using cycloheximide to block the de novo protein synthesis, similar rate of USF2 degradation was found under either normal glucose or high glucose conditions. USF2 mRNA stability was not altered by high glucose treatment. Furthermore, high glucose treatment stimulated USF2 gene promoter activity. By using the luciferase-promoter deletion assay, site-directed mutagenesis, and transactivation assay, we identified a glucose-responsive element in the USF2 gene promoter (-1,740 to -1,620, relative to the transcription start site) and demonstrated that glucose-induced USF2 expression is mediated through a cAMP-response element-binding protein (CREB)-dependent transactivation of the USF2 promoter. Furthermore, siRNA-mediated CREB knock down abolished glucose-induced USF2 expression. Taken together, these data indicate that high glucose levels up-regulate USF2 gene transcription in mesangial cells through CREB-dependent transactivation of the USF2 promoter.
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Affiliation(s)
- Lihua Shi
- Graduate Center for Nutritional Sciences, University of Kentucky, Lexington, Kentucky 40536
| | - Shu Liu
- Graduate Center for Nutritional Sciences, University of Kentucky, Lexington, Kentucky 40536
| | - Dejan Nikolic
- Graduate Center for Nutritional Sciences, University of Kentucky, Lexington, Kentucky 40536
| | - Shuxia Wang
- Graduate Center for Nutritional Sciences, University of Kentucky, Lexington, Kentucky 40536
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Utsunomiya H, Cheng YH, Lin Z, Reierstad S, Yin P, Attar E, Xue Q, Imir G, Thung S, Trukhacheva E, Suzuki T, Sasano H, Kim JJ, Yaegashi N, Bulun SE. Upstream stimulatory factor-2 regulates steroidogenic factor-1 expression in endometriosis. Mol Endocrinol 2007; 22:904-14. [PMID: 18165439 DOI: 10.1210/me.2006-0302] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Local estrogen biosynthesis is a major factor in the pathogenesis of endometriosis. Aberrant expression of steroidogenic acute regulatory protein (StAR) and aromatase in endometriotic tissue leads to an up-regulation of estrogen production. The transcription factor steroidogenic factor-1 (SF-1) activates the promoters of both StAR and aromatase in endometriotic tissue. We investigated differences in SF-1 expression in endometriotic tissue and normally located endometrium to elucidate the mechanism underlying increased StAR and aromatase activities in endometriosis. Serial deletion and site-directed mutants of the SF-1 promoter showed that an E-box sequence was critical for its activity in endometriotic stromal cells. EMSAs showed that the upstream stimulatory factor (USF) 1 and 2 in nuclear extracts from endometrial and endometriotic stromal cells bound to the E-box. Chromatin-immunoprecipitation-PCR assay, however, demonstrated in intact cells that binding activity of USF2 to the SF-1 promoter was strikingly higher than that of USF1 in endometriotic stromal cells and that USF1 or USF2 binding activity was hardly detectable in endometrial stromal cells. Moreover, knockdown of USF2 but not USF1 resulted in robust and consistent down-regulation of SF-1 and its target genes StAR and aromatase in endometriotic stromal cells. USF2 but not USF1 mRNA and protein levels were significantly higher in endometriotic vs. endometrial stromal cells. In vivo, USF2 mRNA and immunoreactive USF2 levels in endometriotic tissues were strikingly higher than those in endometrium. Taken together, the elevated levels of USF2 in endometriosis account for, in part, the aberrant expression of SF-1 and its target gene StAR and aromatase.
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Affiliation(s)
- Hiroki Utsunomiya
- Division of Reproductive Biology Research, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA
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Liu S, Shi L, Wang S. Overexpression of upstream stimulatory factor 2 accelerates diabetic kidney injury. Am J Physiol Renal Physiol 2007; 293:F1727-35. [PMID: 17881461 DOI: 10.1152/ajprenal.00316.2007] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Diabetic nephropathy is the most common cause of end-stage renal failure in the United States. Hyperglycemia is an important factor in the pathogenesis of diabetic nephropathy. Hyperglycemia upregulates the expression of transforming growth factor-beta (TGF-beta), which stimulates extracellular matrix deposition in the kidney, contributing to the development of diabetic nephropathy. Our previous studies demonstrated that the transcription factor, upstream stimulatory factor 2 (USF2), was upregulated by high glucose, which bound to an 18-bp sequence in the thrombospondin 1 (TSP1) gene promoter and regulated high glucose-induced TSP1 expression and TGF-beta activity in mesangial cells, suggesting that USF2 might play a role in the development of diabetic nephropathy. In the present studies, we examined the effect of overexpression of USF2 on the development of diabetic nephropathy. Type 1 diabetes was induced in USF2 transgenic mice [USF2 (Tg)] and their wild-type littermates (WT) by injection of streptozotocin. Four groups of mice were studied: control WT, control USF2 (Tg), diabetic WT, and diabetic USF2 (Tg). Mice were killed after 15 wk of diabetes onset. At the end of studies, control USF2 (Tg) mice ( approximately 6 mo old) exhibited increased urinary albumin excretion. These mice also exhibited glomerular hypertrophy, accompanied by increased TSP1, active TGF-beta, fibronectin accumulation in the glomeruli compared with control WT littermates. Type 1 diabetes onset further augmented the urinary albumin excretion and glomerular hypertrophy in the USF2 (Tg) mice. These findings suggest that overexpression of USF2 accelerates the development of diabetic nephropathy.
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Affiliation(s)
- Shu Liu
- Graduate Center for Nutritional Sciences, University of Kentucky, Wethington Bldg. Rm 517, 900 S. Limestone St., Lexington, KY 40536, USA
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22
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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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Dickson ME, Zimmerman MB, Rahmouni K, Sigmund CD. The -20 and -217 promoter variants dominate differential angiotensinogen haplotype regulation in angiotensinogen-expressing cells. Hypertension 2007; 49:631-9. [PMID: 17200439 DOI: 10.1161/01.hyp.0000254350.62876.b1] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A number of naturally occurring polymorphisms exist in the human angiotensinogen locus, some of which have been associated with essential hypertension, preeclampsia, and other medical disorders. However, to date there has been no comprehensive determination of the significance of specific haplotypes in relation to the regulation of angiotensinogen expression. We cloned the promoters extending from -1219 to +125 bp from 11 ethnically diverse individuals to acquire a representative cross-section of known haplotype diversity. Eight nonredundant haplotypes were identified, fused to luciferase, and studied for their effect on transcriptional regulation in human astrocyte, proximal tubule, and hepatocyte cell lines endogenously expressing angiotensinogen and in a mouse adipocyte cell line. The studies were carried out under baseline conditions, in the presence of the angiotensinogen enhancer, and in response to hormonal stimulation by dexamethasone, beta-estradiol, or testosterone. A statistical model was then constructed to assess the significance of individual polymorphisms. The polymorphisms with the greatest effect on transcription in these cell lines were located at -20 and -217. There were modest haplotype-specific effects of the angiotensinogen enhancer and no haplotype-specific effects of beta-estradiol, dexamethasone, or testosterone treatment. We conclude the following: (1) the -20 and -217 polymorphisms have the largest influence on angiotensinogen transcription, (2) other polymorphisms have a much smaller impact on angiotensinogen transcription, and (3) the transcriptional influence of the promoter polymorphisms may act cell specifically. Therefore, our data support a hypothesis that polymorphisms in the angiotensinogen promoter may act cell specifically to differentially regulate the level of angiotensinogen transcription in angiotensin-producing tissues.
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Affiliation(s)
- Matthew E Dickson
- Interdisciplinary Genetics Program, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City 52242, USA
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Bayele HK, McArdle H, Srai SKS. Cis and trans regulation of hepcidin expression by upstream stimulatory factor. Blood 2006; 108:4237-45. [PMID: 16902156 DOI: 10.1182/blood-2005-07-027037] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
AbstractHepcidin is the presumed negative regulator of systemic iron levels; its expression is induced in iron overload, infection, and inflammation, and by cytokines, but is suppressed in hypoxia and anemia. Although the gene is exquisitely sensitive to changes in iron status in vivo, its mRNA is devoid of prototypical iron-response elements, and it is therefore not obvious how it may be regulated by iron flux. The multiplicity of effectors of its expression also suggests that the transcriptional circuitry controlling the gene may be very complex indeed. In delineating enhancer elements within both the human and mouse hepcidin gene promoters, we show here that members of the basic helix-loop-helix leucine zipper (bHLH-ZIP) family of transcriptional regulators control hepcidin expression. The upstream stimulatory factor 2 (USF2), previously linked to hepcidin through gene ablation in inbred mice, appears to exert a polar or cis-acting effect, while USF1 may act in trans to control hepcidin expression. In mice, we found variation in expression of both hepcidin genes, driven by these transcription factors. In addition, c-Myc and Max synergize to control the expression of this hormone, supporting previous findings for the role of this couple in regulating iron metabolism. Transcriptional activation by both USF1/USF2 and c-Myc/Max heterodimers occurs through E-boxes within the promoter. Site-directed mutagenesis of these elements rendered the promoter unresponsive to USF1/USF2 or c-Myc/Max. Dominant-negative mutants of USF1 and USF2 reciprocally attenuated promoter transactivation by both wild-type USF1 and USF2. Promoter occupancy by the transcription factors was confirmed by DNA-binding and chromatin immunoprecipitation assays. Taken together, it would appear that synergy between these members of the bHLH-ZIP family of transcriptional regulators may subserve an important role in iron metabolism as well as other pathways in which hepcidin may be involved.
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Affiliation(s)
- Henry K Bayele
- Department of Biochemistry & Molecular Biology, University College London, NW3 2PF, United Kingdom
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25
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Zeggini E, Damcott CM, Hanson RL, Karim MA, Rayner NW, Groves CJ, Baier LJ, Hale TC, Hattersley AT, Hitman GA, Hunt SE, Knowler WC, Mitchell BD, Ng MCY, O'Connell JR, Pollin TI, Vaxillaire M, Walker M, Wang X, Whittaker P, Xiang K, Kunsun X, Jia W, Chan JCN, Froguel P, Deloukas P, Shuldiner AR, Elbein SC, McCarthy MI. Variation within the gene encoding the upstream stimulatory factor 1 does not influence susceptibility to type 2 diabetes in samples from populations with replicated evidence of linkage to chromosome 1q. Diabetes 2006; 55:2541-8. [PMID: 16936202 DOI: 10.2337/db06-0088] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The gene encoding the transcription factor upstream stimulatory factor (USF)1 influences susceptibility to familial combined hyperlipidemia (FCHL) and triglyceride levels. Phenotypic overlap between FCHL and type 2 diabetes makes USF1 a compelling positional candidate for the widely replicated type 2 diabetes linkage signal on chromosome 1q. We typed 22 variants in the F11R/USF1 region (1 per 3 kb), including those previously implicated in FCHL-susceptibility (or proxies thereof) in 3,726 samples preferentially enriched for 1q linkage. We also examined glucose- and lipid-related continuous traits in an overlapping set of 1,215 subjects of European descent. There was no convincing evidence for association with type 2 diabetes in any of seven case-control comparisons, individually or combined. Family-based association analyses in 832 Pima subjects were similarly negative. At rs3737787 (the variant most strongly associated with FCHL), the combined odds ratio, per copy of the rarer A-allele, was 1.10 (95% CI 0.97-1.24, P = 0.13). In 124 Utah subjects, rs3737787 was significantly associated (P = 0.002) with triglyceride levels, but direction of this association was opposite to previous reports, and there was no corroboration in three other samples. These data exclude USF1 as a major contributor to type 2 diabetes susceptibility and the basis for the chromosome 1q linkage. They reveal only limited evidence for replication of USF1 effects on continuous metabolic traits.
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Affiliation(s)
- Eleftheria Zeggini
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford OX3 7LJ, UK
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26
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Com E, Rolland AD, Guerrois M, Aubry F, Jégou B, Vallet-Erdtmann V, Pineau C. Identification, molecular cloning, and cellular distribution of the rat homolog of minichromosome maintenance protein 7 (MCM7) in the rat testis. Mol Reprod Dev 2006; 73:866-77. [PMID: 16557521 DOI: 10.1002/mrd.20453] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
As part of a program to decipher the rat testicular proteome, we studied spermatogonia and identified numerous proteins including the human homolog of the Minichromosome Maintenance Protein 7 (MCM7). MCM7 has been implicated in DNA replication in various species, but had not been detected in the testis. Here we describe the cellular distribution of MCM7 transcripts and protein, and their testicular ontogenetic expression. The full-length coding region of the rat MCM7 was also characterized. Northern blot analyses showed that MCM7 transcripts are more abundant in the testis than other organs and confirmed the presence of the 2.4 kb MCM7 transcript at all ages studied. Interestingly, two additional transcripts of 3.2 and 1.6 kb were found from 26 days post partum onwards, when spermatocytes and spermatids accumulate within the tubules. This was confirmed in isolated cell types: the three MCM7 transcripts were observed in meiotic and post-meiotic germ cells. The 3.2 kb isoform has an extended 5' untranslated region (UTR) and the 1.6 kb transcript is the result of alternative splicing of five exons. Western blot and immunohistochemistry experiments evidenced abundant MCM7 in proliferating gonocytes and Sertoli cells in the fetal testis. In the adult testis, an intense signal was observed in spermatogonia and primary spermatocytes. We conclude that the Mcm7 is one example of genes that are differently transcribed and translated in somatic and spermatogenetic cells in mammals. Further work is required to determine the roles of MCM7 in spermatogonia and germ lineage.
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Affiliation(s)
- Emmanuelle Com
- INSERM, U625, GERHM, Campus de Beaulieu, Rennes F-35042, France
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27
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Wang C, Lee G, Hsu W, Yeh CH, Ho ML, Wang GJ. Identification of USF2 as a key regulator of Runx2 expression in mouse pluripotent mesenchymal D1 cells. Mol Cell Biochem 2006; 292:79-88. [PMID: 16786196 DOI: 10.1007/s11010-006-9220-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2006] [Accepted: 05/01/2006] [Indexed: 11/24/2022]
Abstract
Runx2 is one of the most important transcription factors directing the osteogenesis of mesenchymal stem cells and osteoblastic functions. It is likely that the factors controlling Runx2 expression would trigger the early steps of osteoblast differentiation. By using a reporter gene assay for 4.5 kb Runx2 promoter, it was found that the first 305 bp of Runx2 promoter are active in D1 cells. Within this region, electromobility shift assays (EMSAs) delineated a 6 bp of CACATG bound specifically by the proteins from D1 cell nuclear extract. Antibody super-shift and DNA-coupling magnetic bead pull-down assay indicated that the protein bound to this sequence is USF2. Site-specific mutagenesis revealed that this sequence contributed to the activity of 305 bp Runx2 promoter. Thus, we suggest that USF2 might be one of the regulators for the expression of the Runx2 gene in D1 cells.
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Affiliation(s)
- Chihuei Wang
- Department of Biotechnology, Kaohsiung Medical University, Kaohsiung, Taiwan
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28
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Dentin R, Denechaud PD, Benhamed F, Girard J, Postic C. Hepatic gene regulation by glucose and polyunsaturated fatty acids: a role for ChREBP. J Nutr 2006; 136:1145-9. [PMID: 16614395 DOI: 10.1093/jn/136.5.1145] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The liver is a major site for carbohydrate metabolism (glycolysis and glycogen synthesis) and triglyceride synthesis (lipogenesis). In the last decade, increasing evidence has emerged to show that nutrients, in particular, glucose and fatty acids, are able to regulate hepatic gene expression in a transcriptional manner. Indeed, although insulin was long thought to be the major regulator of hepatic gene expression, it is now clear that glucose metabolism rather that glucose itself also contributes substantially to the coordinated regulation of carbohydrate and lipid homeostasis in liver. In fact, the recent discovery of the glucose-signaling transcription factor carbohydrate responsive element binding protein (ChREBP) shed some light on the molecular mechanisms by which glycolytic and lipogenic genes are reciprocally regulated by glucose and fatty acids in liver. Here, we will review some of the recent studies that have begun to elucidate the regulation and function of this key transcription factor in liver. Indeed, a better understanding of the mechanisms by which glucose and fatty acids control hepatic gene expression may provide novel insight into the development of new therapeutic strategies for a better management of diseases involving blood glucose and/or disorders of lipid metabolism.
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Affiliation(s)
- Renaud Dentin
- Institut Cochin, INSERM U567 CNRS UMR8104, Université René Descartes, Département d'Endocrinologie, Métabolisme et Cancer, Paris, France
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29
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Leśniak W, Kuźnicki J. Binding and functional characteristics of two E-box motifs within the S100A6 (calcyclin) gene promoter. J Cell Biochem 2006; 97:1017-24. [PMID: 16288473 DOI: 10.1002/jcb.20699] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
S100A6 (calcyclin) is a small calcium-binding protein of the S100 family often associated with cancer and metastasis. We have previously shown that the E-box sequence at position -283/-278 of the S100A6 gene promoter interacts with USF transcription factor and contributes to promoter transcriptional activity. We now present evidence that a second E-box motif at position -593/-588 of the promoter also binds USF and that the USF1/USF2 heterodimer is the prevailing dimeric form of the transcription factor bound. Using the chromatin immunoprecipitation assay (ChIP), we show that USF is bound in vivo to the E-box regulatory element(s). Depletion of the endogenous USF pool by means of a decoy oligonucleotide evokes a severe inhibition of S100A6 gene promoter activity. Furthermore, we show that S100A6 gene promoter activity can be stimulated by palmitate and that mutation of the -283/-278 E-box sequence completely blocks this stimulation.
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Affiliation(s)
- Wiesława Leśniak
- Department of Molecular and Cellular Neurobiology, Nencki Institute of Experimental Biology, 3 Pasteur street, 02-093 Warsaw, Poland.
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30
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Nakagawa Y, Shimano H, Yoshikawa T, Ide T, Tamura M, Furusawa M, Yamamoto T, Inoue N, Matsuzaka T, Takahashi A, Hasty AH, Suzuki H, Sone H, Toyoshima H, Yahagi N, Yamada N. TFE3 transcriptionally activates hepatic IRS-2, participates in insulin signaling and ameliorates diabetes. Nat Med 2005; 12:107-13. [PMID: 16327801 DOI: 10.1038/nm1334] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2005] [Accepted: 10/27/2005] [Indexed: 11/08/2022]
Abstract
Using an expression cloning strategy, we have identified TFE3, a basic helix-loop-helix protein, as a transactivator of metabolic genes that are regulated through an E-box in their promoters. Adenovirus-mediated expression of TFE3 in hepatocytes in culture and in vivo strongly activated expression of IRS-2 and Akt and enhanced phosphorylation of insulin-signaling kinases such as Akt, glycogen synthase kinase 3beta and p70S6 kinase. TFE3 also induced hexokinase II (HK2) and insulin-induced gene 1 (INSIG1). These changes led to metabolic consequences, such as activation of glycogen and protein synthesis, but not lipogenesis, in liver. Collectively, plasma glucose levels were markedly reduced both in normal mice and in different mouse models of diabetes, including streptozotocin-treated, db/db and KK mice. Promoter analyses showed that IRS2, HK2 and INSIG1 are direct targets of TFE3. Activation of insulin signals in both insulin depletion and resistance suggests that TFE3 could be a therapeutic target for diabetes.
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MESH Headings
- Adenoviridae/genetics
- Adenoviridae/metabolism
- Animals
- Basic Helix-Loop-Helix Leucine Zipper Transcription Factors/metabolism
- Basic Helix-Loop-Helix Leucine Zipper Transcription Factors/physiology
- Blood Glucose/metabolism
- Blotting, Northern
- Cells, Cultured
- Chromatin Immunoprecipitation
- Cloning, Molecular
- Diabetes Mellitus/therapy
- Diabetes Mellitus, Experimental
- Dose-Response Relationship, Drug
- Glycogen/metabolism
- Glycogen Synthase Kinase 3/metabolism
- Glycogen Synthase Kinase 3 beta
- Green Fluorescent Proteins/metabolism
- Hepatocytes/metabolism
- Hexokinase/metabolism
- Humans
- Immunoblotting
- Immunoprecipitation
- Insulin/metabolism
- Insulin Receptor Substrate Proteins
- Intracellular Signaling Peptides and Proteins
- Male
- Membrane Proteins/metabolism
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Models, Biological
- Phosphoproteins/metabolism
- Phosphorylation
- Plasmids/metabolism
- Promoter Regions, Genetic
- Protein Structure, Tertiary
- Proto-Oncogene Proteins c-akt/metabolism
- Rats
- Ribosomal Protein S6 Kinases, 70-kDa/metabolism
- Signal Transduction
- Streptozocin/pharmacology
- Time Factors
- Transcriptional Activation
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Affiliation(s)
- Yoshimi Nakagawa
- Department of Internal Medicine, Metabolism and Endocrinology, Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, Japan, 305-8575
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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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32
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Zhu Y, Casado M, Vaulont S, Sharma K. Role of upstream stimulatory factors in regulation of renal transforming growth factor-beta1. Diabetes 2005; 54:1976-84. [PMID: 15983197 DOI: 10.2337/diabetes.54.7.1976] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
We previously identified an E-box to be implicated in high-glucose-induced transforming growth factor-beta1 (TGF-beta1) gene stimulation in murine mesangial cells. In the present study, we evaluated the role of upstream stimulatory factors (USFs) in mediating glucose-induced stimulation of TGF-beta1. Mesangial cells cultured in glucose concentrations exceeding 2.7 mmol/l D-glucose exhibited increased levels of USF1 and USF2 protein by Western analysis and electrophoretic mobility shift assay (EMSA). An E-box element from the murine TGF-beta1 promoter revealed USF1 and USF2 binding by EMSA. Chromatin immunoprecipitation assay revealed in vivo binding of USF1 to a glucose-responsive region of the TGF-beta1 promoter. Transient cotransfection studies of 293 cells with USF1 led to a twofold increase in TGF-beta1 promoter activity and a 46% increase in secreted TGF-beta1 protein levels. Wild-type and USF2 knockout mice exhibited a 2.5-fold stimulation of renal TGF-beta1 expression upon fasting and refeeding with a carbohydrate-rich diet, whereas USF1 knockout mice exhibited only a minimal increase of renal TGF-beta1 upon refeeding. USF1 mRNA levels were increased in mouse kidneys with carbohydrate refeeding, and USF1 protein was increased in diabetic rat kidneys compared with controls. We conclude that USF1 is stimulated by modest increases in glucose concentration in murine mesangial cells, bind to the murine TGF-beta1 promoter, contribute to carbohydrate-induced renal TGF-beta1 expression, and may play a role in diabetes-related gene regulation in the kidney.
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Affiliation(s)
- Yanqing Zhu
- Department of Medicine, Division of Nephrology, Dorrance Hamilton Research Laboratories, Thomas Jefferson University, Philadelphia, PA 19107, USA
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33
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Thomas BE, Thekkumkara TJ. Glucose mediates transcriptional repression of the human angiotensin type-1 receptor gene: role for a novel cis-acting element. Mol Biol Cell 2004; 15:4347-55. [PMID: 15269283 PMCID: PMC519131 DOI: 10.1091/mbc.e04-03-0203] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Human angiotensin type 1 receptor (hAT1R) gene is regulated by hormones, second messengers, and both pathophysiological and developmental states. The focus of the present study was to determine the role of glucose in the trans-repression of hAT1R gene transcription and to identify the functional cis-acting response element(s). Serial deletions of the hAT1R promoter region indicated that an area between -1717 and -1543 base pairs upstream of the 5' end of the cDNA sequence has a glucose responsive regulatory element (GluRE) to down-regulate the gene expression. Further analysis revealed a putative 29-bp (5'-AACTGATTTTTGTATATTGATCTTGTATT-3') repressor element located between -1582 and -1610 bp was necessary for transcriptional repression. Removal of this region from promoter construct abolished repression of the hAT1R gene transcription in human proximal tubule epithelial cells (hPTECs). Using mobility shift assays, we demonstrated DNA binding activity to the labeled repressor element in hPTEC nuclear extracts. Additional studies demonstrated increased DNA binding activity to the labeled repressor element in nuclear extracts treated with high glucose (25 mM). Southwestern analysis identified two GluRE binding proteins of 34 and 36 kDa in glucose-treated extracts. Glucose-induced activity of the repressor trans-acting factor(s) reached a maximum at 4 h, which correlated with decreased transcriptional activity of the hAT1R gene, suggesting that glucose can down-regulate the transcription of the hAT1R gene through the repressor element. Furthermore, insertion of the glucose response element into heterologous SV40 promoter (SV40) chloramphenicol acetyl transferase (CAT) vector showed orientation/distance-independent repression of SV40 promoter-mediated CAT activity in hPTECs. Our results show that the glucose response factor(s) acts as trans-acting factor(s) binding to the cis-acting repressor element in the hAT1R promoter, which may participate in the control of basal transcription as well as glucose-mediated transcriptional inhibition of the hAT1R gene.
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Affiliation(s)
- Beena E Thomas
- Department of Pharmaceutical Sciences, Texas Tech University Health Sciences Center, Amarillo, TX 79106, USA
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Wang S, Skorczewski J, Feng X, Mei L, Murphy-Ullrich JE. Glucose up-regulates thrombospondin 1 gene transcription and transforming growth factor-beta activity through antagonism of cGMP-dependent protein kinase repression via upstream stimulatory factor 2. J Biol Chem 2004; 279:34311-22. [PMID: 15184388 DOI: 10.1074/jbc.m401629200] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Thrombospondin 1 (TSP1) transcription is stimulated by glucose, resulting in increased TGF-beta activation and matrix protein synthesis. We previously showed that inducible expression of the catalytic domain of cGMP-dependent protein kinase (PKG) inhibits glucose-regulated TSP1 transcription and transforming growth factor (TGF)-beta activity in stably transfected rat mesangial cells (RMCs(tr/cd)). However, the molecular mechanisms by which PKG represses glucose-regulated TSP1 transcription are unknown. Using a luciferase-promoter deletion assay, we now identify a single region of the human TSP1 promoter (-1172 to -878, relative to the transcription start site) that is responsive to glucose. Further characterization of this region identified an 18-bp sequence that specifically binds nuclear proteins from mesangial cells. Moreover, binding is significantly enhanced by high glucose treatment and is reduced by increased PKG activity. Gel mobility shift and supershift assays show that the nuclear proteins binding to the 18-bp sequence are USF1 and -2. USF1 and USF2 bound to the endogenous TSP1 promoter using a chromatin immunoprecipitation assay. Glucose stimulates nuclear USF2 protein accumulation through protein kinase C, p38 MAPK, and extracellular signal-regulated kinase pathways. Increased PKG activity down-regulates USF2 protein levels and its DNA binding activity under high glucose conditions, resulting in inhibition of glucose-induced TSP1 transcription and TGF-beta activity. Overexpression of USF2 reversed the inhibitory effect of PKG on glucose-induced TSP1 gene transcription and TGF-beta activity. Taken together these data present the first evidence that USF2 mediates glucose-induced TSP1 expression and TSP1-dependent TGF-beta bioactivity in mesangial cells, suggesting that USF2 is an important transcriptional regulator of diabetic complications.
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Affiliation(s)
- Shuxia Wang
- Department of Pathology, Division of Molecular and Cellular Pathology, The Cell Adhesion and Matrix Research Center, University of Alabama at Birmingham, Birmingham, AL 35294-0019, USA
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35
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Weigert C, Brodbeck K, Sawadogo M, Häring HU, Schleicher ED. Upstream Stimulatory Factor (USF) Proteins Induce Human TGF-β1 Gene Activation via the Glucose-response Element–1013/–1002 in Mesangial Cells. J Biol Chem 2004; 279:15908-15. [PMID: 14757763 DOI: 10.1074/jbc.m313524200] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The hyperglycemia-enhanced flux through the hexosamine biosynthetic pathway (HBP) has been implicated in the up-regulated gene expression of transforming growth factor-beta1 (TGF-beta1) in mesangial cells, thus leading to mesangial matrix expansion and diabetic glomerulosclerosis. Since the -1013 to -1002 region of the TGF-beta1 promoter shows high homology to glucose-response elements (GlRE) formerly described in genes involved in glucose metabolism, we studied the function of the GlRE in the high glucose-induced TGF-beta1 gene activation in mesangial cells. We found that high glucose concentrations enhanced the nuclear amount of upstream stimulatory factors (USF) and their binding to this sequence. Fusion of the GlRE to the thymidine kinase promoter resulted in glucose responsiveness of this promoter construct. Overexpression of either USF-1 or USF-2 increased TGF-beta1 promoter activity 2-fold, which was prevented by mutation or deletion of the GlRE. The high glucose-induced activation of the GlRE is mediated by the HBP; increased flux through the HBP induced by high glucose concentrations, by glutamine, or by overexpression of the rate-limiting enzyme glutamine:fructose-6-phosphate aminotransferase (GFAT) particularly activated USF-2 expression. GFAT-overexpressing cells showed higher USF binding activity to the GlRE and enhanced promoter activation via the GlRE. Increasing O-GlcNAc modification of proteins by streptozotocin, thereby mimicking HBP activation, also resulted in increased mRNA and nuclear protein levels of USF-2, leading to enhanced DNA binding activity to the GlRE. USF proteins themselves were not found to be O-GlcNAc-modified. Thus, we have provided evidence for a new molecular mechanism linking high glucose-enhanced HBP activity with increased nuclear USF protein levels and DNA binding activity and with up-regulated TGF-beta1 promoter activity.
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Affiliation(s)
- Cora Weigert
- Department of Internal Medicine, Division of Endocrinology, Metabolism and Pathobiochemistry, University of Tübingen, D-72076 Tübingen, Germany
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36
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Stoeckman AK, Ma L, Towle HC. Mlx is the functional heteromeric partner of the carbohydrate response element-binding protein in glucose regulation of lipogenic enzyme genes. J Biol Chem 2004; 279:15662-9. [PMID: 14742444 DOI: 10.1074/jbc.m311301200] [Citation(s) in RCA: 165] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The expression of genes encoding enzymes involved in de novo triglyceride synthesis (lipogenesis) is transcriptionally induced in the liver in response to increased glucose metabolism. The carbohydrate response element-binding protein (ChREBP) is a newly identified basic helix-loop-helix/leucine zipper transcription factor proposed to regulate the expression of the glucose-responsive gene pyruvate kinase. This gene contains a carbohydrate response element (ChoRE) consisting of two E box motifs separated by 5 bp that is necessary and sufficient for glucose regulation. We demonstrate that overexpression of ChREBP in primary rat hepatocytes activates other ChoRE-containing promoters in a manner consistent with their ability to respond to glucose. In vitro binding of ChREBP to ChoRE sequences was not detected. Because E box-binding proteins function as obligate dimers, we performed a yeast two-hybrid screen of a mouse liver cDNA library to identify potential heteromeric partners. Mlx (Max-like protein X) was selected as the only basic helix-loop-helix/leucine zipper interaction partner in this screen. When a plasmid expressing either Mlx or ChREBP was cotransfected with a ChoRE-containing reporter plasmid into human embryonic kidney 293 cells, no increase in promoter activity was observed. However, the expression of both proteins dramatically enhanced promoter activity. This activation was observed with reporters containing ChoREs from several different lipogenic enzyme genes. In contrast, reporters containing non-glucose-responsive E box elements were not activated by ChREBP-Mlx expression. In vitro binding of ChREBP to ChoRE-containing oligonucleotides was observed only in the presence of Mlx. ChREBP-Mlx binding discriminated between E box sites that are glucose-responsive and those that are not. We conclude that Mlx is a functional heteromeric partner of ChREBP in regulating the expression of glucose-responsive genes.
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Affiliation(s)
- Angela K Stoeckman
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, USA
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37
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Boodhoo A, Wong AML, Williamson D, Voon D, Lee S, Allcock RJN, Price P. A promoter polymorphism in the central MHC gene, IKBL, influences the binding of transcription factors USF1 and E47 on disease-associated haplotypes. Gene Expr 2004; 12:1-11. [PMID: 15473256 PMCID: PMC6009106 DOI: 10.3727/000000004783992206] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/24/2004] [Indexed: 11/24/2022]
Abstract
The human major histocompatibility complex (MHC) contains genes that affect susceptibility to numerous immunopathological diseases. We propose that genes in the central MHC between TNFA and HLA-B explain associations between the 8.1 haplotype (HLA-A1, B8, DR3) and disease. IKBL encodes a protein resembling members of the IkappaB protein family that regulate bioavailability of NFkappaB. We have identified two polymorphisms in the 500 bp upstream of the transcription start site of IKBL that distinguish the 8.1 haplotype from the resistant 7.1 haplotype (HLA-A3, B7, DR15). A single nucleotide polymorphism at -62 disrupts a putative E-box binding sequence. To investigate binding of transcription factors in vitro, we exposed 32P-labeled DNA fragments carrying both alleles to nuclear extracts, showing allele-specific binding of nuclear proteins from Jurkat cells but not from other lineages. Supershift studies using Jurkat nuclear extract showed that the E-box protein, E47, and ubiquitously expressed transcription factor USF1 bind to the E-box element of the 7.1 haplotype. Transient transfections of luciferase reporter constructs carrying promoter alleles of IKBL into Jurkat cells showed an effect of IKBL-62 alleles. In contrast, alleles at -421 did not affect transcription factor binding or transcription. IKBL was expressed at low levels in Jurkat cells but not in blood mononuclear cells, and expression declined following mitogenic stimulation. The restriction of IKBL expression to Jurkat cells is consistent with evidence that E47 is expressed in thymocytes and suggests IKBL may affect autoimmunity through an effect on T-cell selection.
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Affiliation(s)
- Alvin Boodhoo
- *University of Mauritius, Reduit, Mauritius
- ‡Department of Clinical Immunology and Biochemical Genetics, Royal Perth Hospital, Perth 6001, Western Australia
| | - Agnes M.-L. Wong
- †School of Surgery and Pathology, University of Western Australia, Nedlands 6009, Western Australia
- ‡Department of Clinical Immunology and Biochemical Genetics, Royal Perth Hospital, Perth 6001, Western Australia
| | - David Williamson
- ‡Department of Clinical Immunology and Biochemical Genetics, Royal Perth Hospital, Perth 6001, Western Australia
| | | | - Silvia Lee
- †School of Surgery and Pathology, University of Western Australia, Nedlands 6009, Western Australia
- ‡Department of Clinical Immunology and Biochemical Genetics, Royal Perth Hospital, Perth 6001, Western Australia
| | - Richard J. N. Allcock
- †School of Surgery and Pathology, University of Western Australia, Nedlands 6009, Western Australia
- ‡Department of Clinical Immunology and Biochemical Genetics, Royal Perth Hospital, Perth 6001, Western Australia
| | - Patricia Price
- †School of Surgery and Pathology, University of Western Australia, Nedlands 6009, Western Australia
- ‡Department of Clinical Immunology and Biochemical Genetics, Royal Perth Hospital, Perth 6001, Western Australia
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Hadsell DL. Genetic Manipulation of Mammary Gland Development and Lactation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2004; 554:229-51. [PMID: 15384580 DOI: 10.1007/978-1-4757-4242-8_20] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The mammalian genome is believed to contain some 30,000 to 40,000 different genes. Of these an estimated 42% have no known function. Genetically engineered mouse models (GEMM) have been a powerful tool available for determining gene function in vivo. In the mammary gland, a variety of genetic engineering approaches have been applied successfully to understanding the importance of specific gene products to mammary gland development and lactation. Our own laboratory has applied genetically engineered mice to facilitate understanding of the regulation of mammary gland development and lactation by insulin-like growth factors (IGF) and by the transcription factor, upstream stimulatory factor (USF-2). Our studies on transgenic mice that overexpress IGF-I have demonstrated the importance of IGF-dependent signaling pathways to maintenance of mammary epithelial cells during the declining phase of lactation. Our analysis of early developmental processes in mammary tissue from mice that carry a targeted mutation in the IGF-I receptor gene suggests that IGF-dependent stimulation of cell cycle progression is more important to early mammary gland development than potential antiapoptotic effects. Lastly, our studies on mice that carry a targeted mutation of the Usf2 gene have demonstrated that this gene is necessary for normal lactation and have highlighted the importance of this gene to the maintenance of protein synthesis. These studies, as well as studies of others, have highlighted both the strengths and limitations inherent in the use of GEMM. Limitations serve as the driving force behind development of new experimental strategies and genetic engineering schemes that will allow for a full understanding of gene function within the mammary gland.
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Affiliation(s)
- Darryl L Hadsell
- The USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA.
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Gimeno-Alcañiz JV, Sanz P. Glucose and type 2A protein phosphatase regulate the interaction between catalytic and regulatory subunits of AMP-activated protein kinase. J Mol Biol 2003; 333:201-9. [PMID: 14516753 DOI: 10.1016/j.jmb.2003.08.022] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
We have expressed in yeast the different subunits of AMP-activated protein kinase (AMPK) and, by using the two-hybrid system, we have found a glucose-regulated interaction between alpha 2 catalytic and gamma 1 regulatory subunits. This regulation was not affected by known regulators of the corresponding yeast orthologue, the SNF1 complex, such as Reg1 or Hxk2, but it was affected by deletion of regulatory subunits of yeast type 2A protein phosphatase (PP2A) complex. We have also found that Tpd3 and PR65 alpha, the corresponding yeast and mammalian A subunits of PP2A, interacted with AMPK alpha 2 both in yeast and mammals, respectively. This interaction occurred only through the regulatory domain of this subunit. These results suggested a direct involvement of PP2A complex in regulating the interaction between AMPK alpha 2 and gamma 1 in a glucose-dependent manner.
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Hadsell DL, Bonnette S, George J, Torres D, Klimentidis Y, Klementidis Y, Gao S, Haney PM, Summy-Long J, Soloff MS, Parlow AF, Sirito M, Sawadogo M. Diminished milk synthesis in upstream stimulatory factor 2 null mice is associated with decreased circulating oxytocin and decreased mammary gland expression of eukaryotic initiation factors 4E and 4G. Mol Endocrinol 2003; 17:2251-67. [PMID: 12907752 DOI: 10.1210/me.2002-0031] [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: 11/19/2022] Open
Abstract
Previous studies have suggested that upstream stimulatory factors (USFs) regulate genes involved with cell cycle progression. Because of the relationship of USFs to an important oncogene in breast cancer, c-myc, we chose to determine the importance of USF to normal mammary gland development in the mouse. Expression of USF in the mammary gland throughout development demonstrated only modest changes. Mutation of the Usf2 gene was associated with reduced fertility in females, but had no effect on prepartum mammary gland development. However, lactation performance in Usf2-/- females was only half of that observed in Usf2+/+ females, and both lactose and nitrogen were decreased in milk from Usf2-/- dams. This decrease was associated with diminished mammary tissue wet weight and luminal area by d 9 of lactation and with a decreased protein-DNA ratio. This decrease was associated with reduced abundance of the eukaryotic initiation factors eIF4E and eIF4G. Blood oxytocin concentrations on d 9 postpartum were also lower in Usf2-/- mice than Usf2+/+ mice. In contrast, the mutation had no effect on blood prolactin concentrations, mammary cell proliferation or apoptosis, mammary tissue oxytocin receptors, or milk protein gene expression. The mutation had only modest effects on maternal behavior. These data support the idea that USF is important to physiological processes necessary for the establishment and maintenance of normal lactation and suggest that USF-2 may impact lactation through both systemic and mammary cell-specific mechanisms.
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Affiliation(s)
- Darryl L Hadsell
- United States Department of Agriculture/Agricultural Research Service Children's Nutrition Research Center, Baylor College of Medicine, Houston, Texas 77030, USA.
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Rodríguez CI, Gironès N, Fresno M. Cha, a basic helix-loop-helix transcription factor involved in the regulation of upstream stimulatory factor activity. J Biol Chem 2003; 278:43135-45. [PMID: 12923186 DOI: 10.1074/jbc.m300053200] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We report here the characterization of Cha, a transcription factor of the basic helix-loop-helix (bHLH) family. The basic region of Cha shares DNA-interacting amino acids with members of class C bHLH transcription factors. In addition, the HLH region of Cha presents a Myc-type dimerization domain signature required for heterodimer formation between members of this class. Cha protein and mRNA were ubiquitously expressed in many human tissues. Electrophoretic mobility shift assays showed that Cha and upstream stimulatory factor (USF)-1 formed a complex that specifically bound to E-box DNA elements. Moreover, pull-down and co-immunoprecipitation experiments showed an interaction between Cha and USF-1. Cha did not bind to E-box DNA elements and required USF-1 for protein-DNA complex formation. Moreover, Cha inhibited USF-1-stimulated transcription of CD2 (a USF-1-dependent gene) and E-box promoter reporter plasmids. Chromatin immunoprecipitation assays showed that Cha occupied the CD2 promoter in resting, but not in mitogen-stimulated, T cells. Finally, Cha mRNA and protein expression were high in resting T cells and absent in mitogen-activated T cells and inversely correlated with CD2 expression. Contrarily, overexpression of Cha in T cells significantly reduced CD2 expression. In summary, our results indicated that Cha is a new bHLH transcription factor that negatively regulates USF-dependent transcription.
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Affiliation(s)
- Clara I Rodríguez
- Centro de Biología Molecular, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Universidad Autónoma de Madrid, Cantoblanco, Madrid 28049, Spain
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Jørgensen SB, Viollet B, Andreelli F, Frøsig C, Birk JB, Schjerling P, Vaulont S, Richter EA, Wojtaszewski JFP. Knockout of the alpha2 but not alpha1 5'-AMP-activated protein kinase isoform abolishes 5-aminoimidazole-4-carboxamide-1-beta-4-ribofuranosidebut not contraction-induced glucose uptake in skeletal muscle. J Biol Chem 2003; 279:1070-9. [PMID: 14573616 DOI: 10.1074/jbc.m306205200] [Citation(s) in RCA: 436] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
We investigated the importance of the two catalytic alpha-isoforms of the 5'-AMP-activated protein kinase (AMPK) in 5-aminoimidazole-4-carboxamide-1-beta-4-ribofuranoside (AICAR) and contraction-induced glucose uptake in skeletal muscle. Incubated soleus and EDL muscle from whole-body alpha2- or alpha1-AMPK knockout (KO) and wild type (WT) mice were incubated with 2.0 mm AICAR or electrically stimulated to contraction. Both AICAR and contraction increased 2DG uptake in WT muscles. KO of alpha2, but not alpha1, abolished AICAR-induced glucose uptake, whereas neither KO affected contraction-induced glucose uptake. AICAR and contraction increased alpha2- and alpha1-AMPK activity in wild type (WT) muscles. During AICAR stimulation, the remaining AMPK activity in KO muscles increased to the same level as in WT. During contraction, the remaining AMPK activity in alpha2-KO muscles was elevated by 100% probably explained by a 2-3-fold increase in alpha1-protein. In alpha1-KO muscles, alpha2-AMPK activity increased to similar levels as in WT. Both interventions increased total AMPK activity, as expressed by AMPK-P and ACCbeta-P, in WT muscles. During AICAR stimulation, this was dramatically reduced in alpha2-KO but not in alpha1-KO, whereas during contraction, both measurements were essentially similar to WT in both KO-muscles. The results show that alpha2-AMPK is the main donor of basal and AICAR-stimulated AMPK activity and is responsible for AICAR-induced glucose uptake. In contrast, during contraction, the two alpha-isoforms seem to substitute for each other in terms of activity, which may explain the normal glucose uptake despite the lack of either alpha2- or alpha1-AMPK. Alternatively, neither alpha-isoform of AMPK is involved in contraction-induced muscle glucose uptake.
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Affiliation(s)
- Sebastian B Jørgensen
- Copenhagen Muscle Research Centre, Department of Human Physiology, 13 Universitetsparken, University of Copenhagen, DK-2100 Copenhagen, Denmark.
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Bidder M, Shao JS, Charlton-Kachigian N, Loewy AP, Semenkovich CF, Towler DA. Osteopontin transcription in aortic vascular smooth muscle cells is controlled by glucose-regulated upstream stimulatory factor and activator protein-1 activities. J Biol Chem 2002; 277:44485-96. [PMID: 12200434 DOI: 10.1074/jbc.m206235200] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The expression of the matrix cytokine osteopontin (OPN) is up-regulated in aortic vascular smooth muscle cells (VSMCs) by diabetes. OPN expression in cultured VSMCs is reciprocally regulated by glucose and 2-deoxyglucose (2-DG; inhibitor of cellular glucose metabolism). Systematic analyses of OPN promoter-luciferase reporter constructs identify a CCTCATGAC motif at nucleotides -80 to -72 relative to the initiation site that supports OPN transcription in VSMCs. The region -83 to -45 encompassing this motif confers basal and glucose- and 2-DG-dependent transcription on an unresponsive promoter. Competition and gel mobility supershift assays identify upstream stimulatory factor (USF; USF1:USF2) and activator protein-1 (AP1; c-Fos:c-Jun) in complexes binding the composite CCTCATGAC element. Glucose up-regulates both AP1 and USF binding activities 2-fold in A7r5 cells and selectively up-regulates USF1 protein levels. By contrast, USF (but not AP1) binding activity is suppressed by 2-DG and restored by glucose treatment. Expression of either USF or AP1 activates the proximal OPN promoter in A7r5 VSMCs in part via the CCTCATGAC element. Moreover, glucose stimulates the transactivation functions of c-Fos and USF1, but not c-Jun, in one-hybrid assays. Mannitol does not regulate binding, transactivation functions, USF1 protein accumulation, or OPN transcription. Thus, OPN gene transcription is regulated by USF and AP1 in aortic VSMCs, entrained to changes in cellular glucose metabolism.
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Affiliation(s)
- Miri Bidder
- Division of Bone and Mineral Diseases, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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Cherqui S, Sevin C, Hamard G, Kalatzis V, Sich M, Pequignot MO, Gogat K, Abitbol M, Broyer M, Gubler MC, Antignac C. Intralysosomal cystine accumulation in mice lacking cystinosin, the protein defective in cystinosis. Mol Cell Biol 2002; 22:7622-32. [PMID: 12370309 PMCID: PMC135682 DOI: 10.1128/mcb.22.21.7622-7632.2002] [Citation(s) in RCA: 136] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cystinosis is an autosomal recessive disorder characterized by an accumulation of intralysosomal cystine. The causative gene, CTNS, encodes cystinosin, a seven-transmembrane-domain protein, which we recently showed to be a lysosomal cystine transporter. The most severe and frequent form of cystinosis, the infantile form, appears around 6 to 12 months, with a proximal tubulopathy (de Toni-Debré-Fanconi syndrome) and ocular damage. End-stage renal failure is reached by 10 years of age. Accumulation of cystine in all tissues eventually leads to multisystemic disease. Treatment with cysteamine, which reduces the concentration of intracellular cystine, delays disease progression but has undesirable side effects. We report the first Ctns knockout mouse model generated using a promoter trap approach. We replaced the last four Ctns exons by an internal ribosome entry site-betagal-neo cassette and showed that the truncated protein was mislocalized and nonfunctional. Ctns(-/-) mice accumulated cystine in all organs tested, and cystine crystals, pathognomonic of cystinosis, were observed. Ctns(-/-) mice developed ocular changes similar to those observed in affected individuals, bone defects and behavioral anomalies. Interestingly, Ctns(-/-) mice did not develop signs of a proximal tubulopathy, or renal failure. A preliminary therapeutic trial using an oral administration of cysteamine was carried out and demonstrated the efficiency of this treatment for cystine clearance in Ctns(-/-) mice. This animal model will prove an invaluable and unique tool for testing emerging therapeutics for cystinosis.
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Abstract
The E-Box is a widely used DNA control element. Despite its brevity and broad distribution the E-Box is a remarkably versatile sequence that affects many different genetic programs, including proliferation, differentiation, tissue-specific responses, and cell death. The circadian clock is one of the latest pathways shown to employ this element. In this context, E-Boxes are likely to play a key role in establishing the robust waves of gene expression characteristic of circadian transcription. The regulatory flexibility of the E-Box hinges on the sequence ambiguity allowed at its core, the strong influence of the surrounding sequences, and the recruitment of spatially and temporally regulated E-Box-binding factors. Therefore, understanding how a particular E-Box can accomplish a specific task entails the identification and systematic analysis of these cis- and trans-acting E-Box modifiers. In the present study we compared the E-Box-containing minimal promoters of vasopressin and cyclin B1, two genes that can respond to the transcriptional oscillators driving the circadian clock and cell cycle, respectively. Results of this comparison will help elucidate the manner in which discreet DNA modules associate to either augment or restrain the activation of potential circadian E-Boxes in response to competing regulatory signals.
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Affiliation(s)
- Estela Muñoz
- Unit on Temporal Gene Expression, Laboratory of Cellular and Molecular Regulation, National Institute of Mental Health, Bethesda, Maryland 20892, USA
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46
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Wang H, Wollheim CB. ChREBP rather than USF2 regulates glucose stimulation of endogenous L-pyruvate kinase expression in insulin-secreting cells. J Biol Chem 2002; 277:32746-52. [PMID: 12087089 DOI: 10.1074/jbc.m201635200] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
There is controversy whether or not upstream stimulatory factors (USF) regulate the glucose responsiveness of L-pyruvate kinase (L-PK) promoter activity in hepatocytes. It has been suggested that USF-2 is required for glucose stimulation of L-PK promoter activity in single islet beta-cells and INS-1 cells (Kennedy, H. J., Viollet, B., Rafiq, I., Kahn, A., and Rutter, G. A. (1997) J. Biol. Chem. 272, 20636-20640). In the present study, the tet-on system has been employed to achieve tightly controlled and inducible expression of USF-1 and -2 and their dominant-negative mutants DN-USF-1 (DeltabTDU1) and -2 (TDU2) in INS-1 cells. Quantitative Northern blot analysis shows that neither basal level nor glucose responsiveness of endogenous L-PK mRNA is affected by overexpression of USF-1 and -2. Likewise, the L-PK expression is unaltered by dominant-negative suppression of USF function. Western blotting demonstrates that USF-1 and -2 and DN-USF-1 and -2 proteins are stably expressed in nuclear fractions of INS-1 cells. Immunofluorescence staining indicates the uniform induction of these transgene-encoded proteins in the cell nuclei. Electrophoretic mobility shift assays using the L-PK promoter segment reveal that induction of USF-1 and -2 dramatically enhances the USF binding activity, whereas DN-USF-1 and -2 abolish binding. DN-USF-1 and -2 exert their dominant-negative effect by forming non-functional heterodimers with endogenous USF proteins. Carbohydrate response element-binding protein (ChREBP) was recently shown to regulate the glucose responsiveness of the L-PK promoter activity in hepatocytes. We now report the presence of this transcription factor in rat islets and INS-1 cells. Glucose stimulates ChREBP transcription in INS-1 cells, as shown by nuclear run-on experiments. Overexpression of ChREBP in INS-1 cells using the tet-on system results in a left shift of glucose responsiveness of L-PK expression and an enhanced L-PK promoter activity. Both endogenous and doxycycline-induced ChREBP proteins bind to the L-PK promoter in a glucose-dependent manner. These unprecedented results suggest that ChREBP rather than USF mediates glucose-promoted L-PK expression in insulin-secreting cells.
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MESH Headings
- Animals
- Basic Helix-Loop-Helix Leucine Zipper Transcription Factors
- Blotting, Northern
- Blotting, Western
- Cell Nucleus/metabolism
- Cloning, Molecular
- DNA, Complementary/metabolism
- DNA-Binding Proteins/metabolism
- Dose-Response Relationship, Drug
- Down-Regulation
- Genes, Dominant
- Glucose/metabolism
- Glucose/pharmacology
- Hepatocytes/metabolism
- Immunoblotting
- Insulin/metabolism
- Luciferases/metabolism
- Mice
- Microscopy, Fluorescence
- Plasmids/metabolism
- Promoter Regions, Genetic
- Protein Binding
- Pyruvate Kinase/metabolism
- RNA, Messenger/metabolism
- Subcellular Fractions
- Time Factors
- Transcription Factors/metabolism
- Transcription, Genetic
- Transcriptional Activation
- Transfection
- Up-Regulation
- Upstream Stimulatory Factors
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Affiliation(s)
- Haiyan Wang
- Division of Clinical Biochemistry, Department of Internal Medicine, University Medical Center, CH-1211 Geneva 4, Switzerland.
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Kietzmann T, Krones-Herzig A, Jungermann K. Signaling cross-talk between hypoxia and glucose via hypoxia-inducible factor 1 and glucose response elements. Biochem Pharmacol 2002; 64:903-11. [PMID: 12213585 DOI: 10.1016/s0006-2952(02)01160-7] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The substrates oxygen and glucose are important for the appropriate regulation of metabolism, angiogenesis, tumorigenesis and embryonic development. The knowledge about an interaction between these two signals is limited. We demonstrated that the regulation of glucagon receptor, insulin receptor and L-type pyruvate kinase (L-PK) gene expression in liver is dependent upon a cross-talk between oxygen and glucose. The periportal to perivenous drop in O2 tension was proposed to be an endocrine key regulator for the zonated gene expression in liver. In primary rat hepatocyte cultures, the expression of the glucagon receptor and the L-PK mRNA was maximally induced by glucose under arterial pO2 whereas the insulin receptor was maximally induced under perivenous pO2. It was demonstrated for the L-PK gene that the modulation by O2 of the glucose-dependent induction occured at the glucose-responsive element (Glc(PK)RE) in the L-PK gene promoter. The reduction of the glucose-dependent induction of the L-PK gene expression under venous pO2 appeared to be mediated via an interference between hypoxia-inducible factor 1 (HIF-1) and the glucose-responsive transcription factors at the Glc(PK)RE. The glucose response element (GlcRE) also functioned as a hypoxia response element and, vice versa, a hypoxia-responsive element was functioning as a GlcRE. Thus, our findings implicate that the cross-talk between oxygen and glucose might have a fundamental role in the regulation of several physiological and pathophysiological processes.
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Affiliation(s)
- Thomas Kietzmann
- Institut für Biochemie und Molekulare Zellbiologie, Georg-August-Universität, Humboldtallee 23, D-37073 Göttingen, Germany.
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48
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Takahashi K, Nishiyama C, Ra C. Transcriptional regulation of the human high affinity IgE receptor alpha-chain gene. Mol Immunol 2002; 38:1193-9. [PMID: 12217383 DOI: 10.1016/s0161-5890(02)00062-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Transcriptional regulation of the gene encoding human high affinity IgE receptor (Fc epsilon RI) alpha-chain was analyzed. Previously, we reported that GATA-1 and Elf-1 recognition sites were necessary for cell type-specific activation of the alpha-chain gene promoter. More detailed analysis revealed that other transcription factors bound the regions close to the Elf-1 recognition site and there was a more complex mechanism for the regulation of the promoter activity. On the other hand, during a course of studies to find cis-elements over this gene, CAGCTG sequence in the first intron was revealed to serve as an enhancer. A complex composed of USF1 and USF2 activated the human alpha-chain gene expression via this intronic element. Furthermore, we found two novel exons at 18.4 and 12.6kb upstream from the reported first exon and discovered an additional distal promoter.
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Affiliation(s)
- Kyoko Takahashi
- Department of Molecular Cell Immunology and Allergology, Advanced Medical Research Center, Nihon University School of Medicine, 30-1 Oyaguchi-kamimachi, Itabashi-ku, 173-8610, Tokyo, Japan
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49
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Foufelle F, Ferré P. New perspectives in the regulation of hepatic glycolytic and lipogenic genes by insulin and glucose: a role for the transcription factor sterol regulatory element binding protein-1c. Biochem J 2002; 366:377-91. [PMID: 12061893 PMCID: PMC1222807 DOI: 10.1042/bj20020430] [Citation(s) in RCA: 361] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2002] [Revised: 05/27/2002] [Accepted: 06/13/2002] [Indexed: 02/07/2023]
Abstract
The regulation of hepatic glucose metabolism has a key role in whole-body energy metabolism, since the liver is able to store (glycogen synthesis, lipogenesis) and to produce (glycogenolysis, gluconeogenesis) glucose. These pathways are regulated at several levels, including a transcriptional level, since many of the metabolism-related genes are expressed according to the quantity and quality of nutrients. Recent advances have been made in the understanding of the regulation of hepatic glycolytic, lipogenic and gluconeogenic gene expression by pancreatic hormones, insulin and glucagon and glucose. Here we review the role of the transcription factors forkhead and sterol regulatory element binding protein-1c in the inductive and repressive effects of insulin on hepatic gene expression, and the pathway that leads from glucose to gene regulation with the recently discovered carbohydrate response element binding protein. We discuss how these transcription factors are integrated in a regulatory network that allows a fine tuning of hepatic glucose storage or production, and their potential importance in metabolic diseases.
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Affiliation(s)
- Fabienne Foufelle
- INSERM Unit 465, Centre de Recherches Biomédicales des Cordeliers, 15 rue de l'Ecole de Médecine, 75270 Paris Cedex 06, France.
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50
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Tannour-Louet M, Porteu A, Vaulont S, Kahn A, Vasseur-Cognet M. A tamoxifen-inducible chimeric Cre recombinase specifically effective in the fetal and adult mouse liver. Hepatology 2002; 35:1072-81. [PMID: 11981757 DOI: 10.1053/jhep.2002.33164] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
The spatiotemporal control of somatic mutagenesis in mice is considered a promising step to determine the function of a given gene product in a defined population of cells at any given time during animal life and also to generate better mouse models of human diseases. To introduce defined mutations in a temporally controlled manner in the liver, we established transgenic mice expressing a tamoxifen-inducible Cre recombinase under the control of the transthyretin promoter (TTR-Cre ind). The recombinase activity was examined on 2 different floxed alleles by crossing TTR-Cre ind mice with either the reporter strain ROSA 26 or with homozygous mice carrying floxed catalytic alpha2 subunit of the adenosine monophosphate (AMP)-activated protein kinase gene. By placing 2 mutated hormone-binding domains of murine estrogen receptor (Mer) at both termini of the Cre, we show that the fusion protein is active only on administration of the synthetic estrogen antagonist 4-hydroxytamoxifen (4-OHT) without any background in the absence of the inducing agent. The recombination is specific of the fetal and adult liver, and we show that the efficiency of recombination reached 80% to 100% after treatment with 4-OHT. In conclusion, TTR-Cre ind transgenic mice represent a valuable tool for temporally controlling the desired gene modifications in vivo in the fetal and adult liver. This would certainly help to understand the physiologic functions of genes in the liver, to create various mouse models mimicking human diseases, and to contribute to liver cancer-specific suicide gene therapy studies.
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Affiliation(s)
- Mounia Tannour-Louet
- Institut Cochin U567, Département de Génétique, Développement et Physiopathologie Moléculaires, INSERM U129, Paris, France
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