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Tao Y, Zou T, Zhang X, Liu R, Chen H, Yuan G, Zhou D, Xiong P, He Z, Li G, Zhou M, Liu S, Deng Q, Wang S, Zhu J, Liang Y, Yu X, Zheng A, Wang A, Liu H, Wang L, Li P, Li S. Secretory lipid transfer protein OsLTPL94 acts as a target of EAT1 and is required for rice pollen wall development. Plant J 2021; 108:358-377. [PMID: 34314535 DOI: 10.1111/tpj.15443] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 07/21/2021] [Indexed: 06/13/2023]
Abstract
The plant pollen wall protects the male gametophyte from various biotic and abiotic stresses. The formation of a unique pollen wall structure and elaborate exine pattern is a well-organized process, which needs coordination between reproductive cells and the neighboring somatic cells. However, molecular mechanisms underlying this process remain largely unknown. Here, we report a rice male-sterile mutant (l94) that exhibits defective pollen exine patterning and abnormal tapetal cell development. MutMap and knockout analyses demonstrated that the causal gene encodes a type-G non-specific lipid transfer protein (OsLTPL94). Histological and cellular analyses established that OsLTPL94 is strongly expressed in the developing microspores and tapetal cells, and its protein is secreted to the plasma membrane. The l94 mutation impeded the secretory ability of OsLTPL94 protein. Further in vivo and in vitro investigations supported the hypothesis that ETERNAL TAPETUM 1 (EAT1), a basic helix-loop-helix transcription factor (bHLH TF), activated OsLTPL94 expression through direct binding to the E-box motif of the OsLTPL94 promoter, which was supported by the positive correlation between the expression of EAT1 and OsLTPL94 in two independent eat1 mutants. Our findings suggest that the secretory OsLTPL94 plays a key role in the coordinated development of tapetum and microspores with the regulation of EAT1.
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Affiliation(s)
- Yang Tao
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu, 611130, China
| | - Ting Zou
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu, 611130, China
- State Key Laboratory of Hybrid Rice, Rice Research Institute, Sichuan Agricultural University, Chengdu, 611130, China
| | - Xu Zhang
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu, 611130, China
| | - Rui Liu
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu, 611130, China
| | - Hao Chen
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu, 611130, China
| | - Guoqiang Yuan
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu, 611130, China
| | - Dan Zhou
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu, 611130, China
| | - Pingping Xiong
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu, 611130, China
| | - Zhiyuan He
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu, 611130, China
| | - Gongwen Li
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu, 611130, China
| | - Menglin Zhou
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu, 611130, China
| | - Sijing Liu
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu, 611130, China
| | - Qiming Deng
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu, 611130, China
- State Key Laboratory of Hybrid Rice, Rice Research Institute, Sichuan Agricultural University, Chengdu, 611130, China
| | - Shiquan Wang
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu, 611130, China
- State Key Laboratory of Hybrid Rice, Rice Research Institute, Sichuan Agricultural University, Chengdu, 611130, China
| | - Jun Zhu
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu, 611130, China
- State Key Laboratory of Hybrid Rice, Rice Research Institute, Sichuan Agricultural University, Chengdu, 611130, China
| | - Yueyang Liang
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu, 611130, China
- State Key Laboratory of Hybrid Rice, Rice Research Institute, Sichuan Agricultural University, Chengdu, 611130, China
| | - Xiumei Yu
- College of Resource, Sichuan Agricultural University, Chengdu, 611130, China
| | - Aiping Zheng
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu, 611130, China
- State Key Laboratory of Hybrid Rice, Rice Research Institute, Sichuan Agricultural University, Chengdu, 611130, China
| | - Aijun Wang
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu, 611130, China
- State Key Laboratory of Hybrid Rice, Rice Research Institute, Sichuan Agricultural University, Chengdu, 611130, China
| | - Huainian Liu
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu, 611130, China
- State Key Laboratory of Hybrid Rice, Rice Research Institute, Sichuan Agricultural University, Chengdu, 611130, China
| | - Lingxia Wang
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu, 611130, China
- State Key Laboratory of Hybrid Rice, Rice Research Institute, Sichuan Agricultural University, Chengdu, 611130, China
| | - Ping Li
- State Key Laboratory of Hybrid Rice, Rice Research Institute, Sichuan Agricultural University, Chengdu, 611130, China
| | - Shuangcheng Li
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu, 611130, China
- State Key Laboratory of Hybrid Rice, Rice Research Institute, Sichuan Agricultural University, Chengdu, 611130, China
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Kaufman ML, Goodson NB, Park KU, Schwanke M, Office E, Schneider SR, Abraham J, Hensley A, Jones KL, Brzezinski JA. Initiation of Otx2 expression in the developing mouse retina requires a unique enhancer and either Ascl1 or Neurog2 activity. Development 2021; 148:dev199399. [PMID: 34143204 PMCID: PMC8254865 DOI: 10.1242/dev.199399] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 05/10/2021] [Indexed: 11/20/2022]
Abstract
During retinal development, a large subset of progenitors upregulates the transcription factor Otx2, which is required for photoreceptor and bipolar cell formation. How these retinal progenitor cells initially activate Otx2 expression is unclear. To address this, we investigated the cis-regulatory network that controls Otx2 expression in mice. We identified a minimal enhancer element, DHS-4D, that drove expression in newly formed OTX2+ cells. CRISPR/Cas9-mediated deletion of DHS-4D reduced OTX2 expression, but this effect was diminished in postnatal development. Systematic mutagenesis of the enhancer revealed that three basic helix-loop-helix (bHLH) transcription factor-binding sites were required for its activity. Single cell RNA-sequencing of nascent Otx2+ cells identified the bHLH factors Ascl1 and Neurog2 as candidate regulators. CRISPR/Cas9 targeting of these factors showed that only the simultaneous loss of Ascl1 and Neurog2 prevented OTX2 expression. Our findings suggest that Ascl1 and Neurog2 act either redundantly or in a compensatory fashion to activate the DHS-4D enhancer and Otx2 expression. We observed redundancy or compensation at both the transcriptional and enhancer utilization levels, suggesting that the mechanisms governing Otx2 regulation in the retina are flexible and robust.
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Affiliation(s)
- Michael L. Kaufman
- Department of Ophthalmology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Noah B. Goodson
- Department of Ophthalmology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Ko Uoon Park
- Department of Ophthalmology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Michael Schwanke
- Department of Ophthalmology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Emma Office
- Department of Ophthalmology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Sophia R. Schneider
- Department of Ophthalmology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Joy Abraham
- Department of Ophthalmology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Austin Hensley
- Department of Ophthalmology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Kenneth L. Jones
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Joseph A. Brzezinski
- Department of Ophthalmology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
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3
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Cal-Kayitmazbatir S, Kulkoyluoglu-Cotul E, Growe J, Selby CP, Rhoades SD, Malik D, Oner H, Asimgil H, Francey LJ, Sancar A, Kruger WD, Hogenesch JB, Weljie A, Anafi RC, Kavakli IH. CRY1-CBS binding regulates circadian clock function and metabolism. FEBS J 2021; 288:614-639. [PMID: 32383312 PMCID: PMC7648728 DOI: 10.1111/febs.15360] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 04/09/2020] [Accepted: 05/04/2020] [Indexed: 12/13/2022]
Abstract
Circadian disruption influences metabolic health. Metabolism modulates circadian function. However, the mechanisms coupling circadian rhythms and metabolism remain poorly understood. Here, we report that cystathionine β-synthase (CBS), a central enzyme in one-carbon metabolism, functionally interacts with the core circadian protein cryptochrome 1 (CRY1). In cells, CBS augments CRY1-mediated repression of the CLOCK/BMAL1 complex and shortens circadian period. Notably, we find that mutant CBS-I278T protein, the most common cause of homocystinuria, does not bind CRY1 or regulate its repressor activity. Transgenic CbsZn/Zn mice, while maintaining circadian locomotor activity period, exhibit reduced circadian power and increased expression of E-BOX outputs. CBS function is reciprocally influenced by CRY1 binding. CRY1 modulates enzymatic activity of the CBS. Liver extracts from Cry1-/- mice show reduced CBS activity that normalizes after the addition of exogenous wild-type (WT) CRY1. Metabolomic analysis of WT, CbsZn/Zn , Cry1-/- , and Cry2-/- samples highlights the metabolic importance of endogenous CRY1. We observed temporal variation in one-carbon and transsulfuration pathways attributable to CRY1-induced CBS activation. CBS-CRY1 binding provides a post-translational switch to modulate cellular circadian physiology and metabolic control.
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Affiliation(s)
- Sibel Cal-Kayitmazbatir
- Department Molecular Biology and Genetics, Koc University
Rumelifeneri Yolu, Sariyer, Istanbul, Turkey
| | - Eylem Kulkoyluoglu-Cotul
- Department Chemical and Biological Engineering Koc
University Rumelifeneri Yolu, Sariyer, Istanbul, Turkey
| | - Jacqueline Growe
- Systems Pharmacology and Translational Therapeutics,
University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Christopher P. Selby
- Department of Biochemistry and Biophysics, University of
North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Seth D. Rhoades
- Systems Pharmacology and Translational Therapeutics,
University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Dania Malik
- Systems Pharmacology and Translational Therapeutics,
University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Hasimcan Oner
- Department Chemical and Biological Engineering Koc
University Rumelifeneri Yolu, Sariyer, Istanbul, Turkey
| | - Hande Asimgil
- Department Chemical and Biological Engineering Koc
University Rumelifeneri Yolu, Sariyer, Istanbul, Turkey
| | - Lauren J. Francey
- Divisions of Human Genetics and Immunobiology, Cincinnati
Children’s Hospital Medical Center, Cincinnati, OH, USA
| | - Aziz Sancar
- Department of Biochemistry and Biophysics, University of
North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Warren D. Kruger
- Cancer Biology Program, Fox Chase Cancer Center,
Philadelphia, PA, USA
| | - John B. Hogenesch
- Systems Pharmacology and Translational Therapeutics,
University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Divisions of Human Genetics and Immunobiology, Cincinnati
Children’s Hospital Medical Center, Cincinnati, OH, USA
| | - Aalim Weljie
- Systems Pharmacology and Translational Therapeutics,
University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Ron C. Anafi
- Department of Medicine, Chronobiology and Sleep Institute,
University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Ibrahim Halil Kavakli
- Department Molecular Biology and Genetics, Koc University
Rumelifeneri Yolu, Sariyer, Istanbul, Turkey
- Department Chemical and Biological Engineering Koc
University Rumelifeneri Yolu, Sariyer, Istanbul, Turkey
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4
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Freeman SL, Kwon H, Portolano N, Parkin G, Venkatraman Girija U, Basran J, Fielding AJ, Fairall L, Svistunenko DA, Moody PCE, Schwabe JWR, Kyriacou CP, Raven EL. Heme binding to human CLOCK affects interactions with the E-box. Proc Natl Acad Sci U S A 2019; 116:19911-19916. [PMID: 31527239 PMCID: PMC6778266 DOI: 10.1073/pnas.1905216116] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The circadian clock is an endogenous time-keeping system that is ubiquitous in animals and plants as well as some bacteria. In mammals, the clock regulates the sleep-wake cycle via 2 basic helix-loop-helix PER-ARNT-SIM (bHLH-PAS) domain proteins-CLOCK and BMAL1. There is emerging evidence to suggest that heme affects circadian control, through binding of heme to various circadian proteins, but the mechanisms of regulation are largely unknown. In this work we examine the interaction of heme with human CLOCK (hCLOCK). We present a crystal structure for the PAS-A domain of hCLOCK, and we examine heme binding to the PAS-A and PAS-B domains. UV-visible and electron paramagnetic resonance spectroscopies are consistent with a bis-histidine ligated heme species in solution in the oxidized (ferric) PAS-A protein, and by mutagenesis we identify His144 as a ligand to the heme. There is evidence for flexibility in the heme pocket, which may give rise to an additional Cys axial ligand at 20K (His/Cys coordination). Using DNA binding assays, we demonstrate that heme disrupts binding of CLOCK to its E-box DNA target. Evidence is presented for a conformationally mobile protein framework, which is linked to changes in heme ligation and which has the capacity to affect binding to the E-box. Within the hCLOCK structural framework, this would provide a mechanism for heme-dependent transcriptional regulation.
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Affiliation(s)
- Samuel L Freeman
- School of Chemistry, University of Bristol, BS8 1TS Bristol, United Kingdom
| | - Hanna Kwon
- School of Chemistry, University of Bristol, BS8 1TS Bristol, United Kingdom
| | - Nicola Portolano
- Department of Chemistry, University of Leicester, LE1 7RH Leicester, United Kingdom
- Leicester Institute of Structural and Chemical Biology, University of Leicester, LE1 7RH Leicester, United Kingdom
| | - Gary Parkin
- Department of Chemistry, University of Leicester, LE1 7RH Leicester, United Kingdom
- Leicester Institute of Structural and Chemical Biology, University of Leicester, LE1 7RH Leicester, United Kingdom
| | - Umakhanth Venkatraman Girija
- Department of Chemistry, University of Leicester, LE1 7RH Leicester, United Kingdom
- Leicester Institute of Structural and Chemical Biology, University of Leicester, LE1 7RH Leicester, United Kingdom
| | - Jaswir Basran
- Department of Chemistry, University of Leicester, LE1 7RH Leicester, United Kingdom
- Leicester Institute of Structural and Chemical Biology, University of Leicester, LE1 7RH Leicester, United Kingdom
| | - Alistair J Fielding
- School of Pharmacy and Biomolecular Science, Liverpool John Moores University, Liverpool L3 3AF, United Kingdom
| | - Louise Fairall
- Leicester Institute of Structural and Chemical Biology, University of Leicester, LE1 7RH Leicester, United Kingdom
- Department of Molecular and Cell Biology, University of Leicester, LE1 7RH Leicester, United Kingdom
| | - Dimitri A Svistunenko
- School of Biological Sciences, University of Essex, Colchester, Essex CO4 3SQ, United Kingdom
| | - Peter C E Moody
- Leicester Institute of Structural and Chemical Biology, University of Leicester, LE1 7RH Leicester, United Kingdom
- Department of Molecular and Cell Biology, University of Leicester, LE1 7RH Leicester, United Kingdom
| | - John W R Schwabe
- Leicester Institute of Structural and Chemical Biology, University of Leicester, LE1 7RH Leicester, United Kingdom
- Department of Molecular and Cell Biology, University of Leicester, LE1 7RH Leicester, United Kingdom
| | - Charalambos P Kyriacou
- Department of Genetics and Genome Biology, University of Leicester, LE1 7RH Leicester, United Kingdom
| | - Emma L Raven
- School of Chemistry, University of Bristol, BS8 1TS Bristol, United Kingdom;
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5
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Wu PL, Zhou Y, Zeng C, Li X, Dong ZT, Zhou YF, Bulun SE, Xue Q. Transcription factor 21 regulates expression of ERβ and SF-1 via upstream stimulatory factor-2 in endometriotic tissues. Biochim Biophys Acta Gene Regul Mech 2018; 1861:706-717. [PMID: 30018006 DOI: 10.1016/j.bbagrm.2018.06.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 06/07/2018] [Accepted: 06/21/2018] [Indexed: 11/19/2022]
Abstract
Steroidogenic factor-1 (SF-1, encoded by NR5A1) and estrogen receptor beta (ERβ, encoded by ESR2), which are highly expressed in endometriotic stromal cells (ESCs), contribute to the pathogenesis of endometriosis, but the regulation mechanism remains largely unknown. Transcription factor 21 (TCF21) belongs to the helix-loop-helix (bHLH) family characterized by regulating gene expression via binding to E-box element. Here, we attempted to determine the molecular mechanism of TCF21 on SF-1 and ERβ expression in endometriosis. We found that TCF21 expression in ESCs was higher than that in endometrial stromal cells (EMs), and positively correlated with SF-1 and ERβ expression in ESCs. Since the importance of E-box element for NR5A1 promoter activity has been previously reported, we performed site-mutation and luciferase assay, revealing that the E-box sequence in the ESR2 promoter is also a critical element modulating ERβ expression. Upstream stimulatory factor 2 (USF2) is another bHLH factor implicated in transcriptional regulation. Further analyses elucidated that it is not TCF21, but USF2 exhibited higher binding affinities in ESCs to NR5A1 and ESR2 promoters than in EMs. Additionally, TCF21 knockdown significantly decreased the binding activities of USF2 to NR5A1 and ESR2 promoters via disruption of the TCF21-USF2 complex. Meanwhile, manipulating TCF21 expression significantly affected MMP9 and cyclinD1 expression, as wells as proliferation and invasion of ESCs. Moreover, TCF21 depletion in endometriotic xenografts reduced SF-1 and ERβ expression, abrogating ectopic lesion growth in mice. Cumulatively, a critical role of TCF21 in the pathogenesis of endometriosis is demonstrated, suggesting a potential druggable target for future therapy.
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Affiliation(s)
- Pei-Li Wu
- Department of Obstetrics and Gynecology, Peking University First Hospital, Beijing 100034, China
| | - Yan Zhou
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China
| | - Cheng Zeng
- Department of Obstetrics and Gynecology, Peking University First Hospital, Beijing 100034, China
| | - Xin Li
- Department of Obstetrics and Gynecology, Peking University First Hospital, Beijing 100034, China
| | - Zhao-Tong Dong
- Department of Obstetrics and Gynecology, Peking University First Hospital, Beijing 100034, China
| | - Ying-Fang Zhou
- Department of Obstetrics and Gynecology, Peking University First Hospital, Beijing 100034, China
| | - Serdar E Bulun
- Department of Obstetrics and Gynecology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Qing Xue
- Department of Obstetrics and Gynecology, Peking University First Hospital, Beijing 100034, China.
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6
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Jang J, Chung S, Choi Y, Lim HY, Son Y, Chun SK, Son GH, Kim K, Suh YG, Jung JW. The cryptochrome inhibitor KS15 enhances E-box-mediated transcription by disrupting the feedback action of a circadian transcription-repressor complex. Life Sci 2018; 200:49-55. [PMID: 29534992 DOI: 10.1016/j.lfs.2018.03.022] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 02/28/2018] [Accepted: 03/09/2018] [Indexed: 11/25/2022]
Abstract
AIMS We have previously identified a chemical scaffold possessing 2-ethoxypropanoic acid (designated as KS15) that directly binds to the C-terminal region of cryptochromes (CRYs: CRY1 and CRY2) and enhances E-box-mediated transcription. However, it is still unclear how KS15 impairs the feedback actions of the CRYs and which chemical moieties are functionally important for its actions. MAIN METHODS The E-box-mediated transcriptional activities were mainly used to examine the effects of KS15 and its derivatives. Co-immunoprecipitation assays accompanied by immunoblotting were employed to monitor protein-protein associations. We also examined the effects of KS15 and selected derivatives on circadian molecular rhythms in cultured cells. KEY FINDINGS The present study shows that KS15 inhibits the interaction between CRYs and Brain-Muscle-Arnt-Like protein 1 (BMAL1), thereby impairing the feedback actions of CRYs on E-box-dependent transcription by CLOCK:BMAL1 heterodimer, an indispensable transcriptional regulator of the mammalian circadian clock. Subsequent structure-activity relationship analyses using a well-designed panel of derivatives identified the structural requirements for the effects of KS15 on CRY-evoked regulation of E-box-mediated transcription. We found that KS15 and several derivatives significantly reduce the amplitude and delayed the phase of molecular circadian rhythms in fibroblast cultures. SIGNIFICANCE Taken together, our results provide valuable information on the molecular mode-of-action as well as the chemical components of the CRYs inhibitor that pharmacologically impact on the transcriptional activity of the CLOCK:BMAL1 heterodimer.
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Affiliation(s)
- Jaebong Jang
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Sooyoung Chung
- Department of Brain and Cognitive Sciences, Scranton College, Ewha Womans University, Seoul, Republic of Korea
| | - Youjeong Choi
- College of Pharmacy, Research Institute of Pharmaceutical Sciences, Kyungpook National University, Daegu, Republic of Korea
| | - Hye Young Lim
- Department of Biomedical Sciences, College of Medicine, Korea University, Seoul, Republic of Korea
| | - Yeongeon Son
- College of Pharmacy, Research Institute of Pharmaceutical Sciences, Kyungpook National University, Daegu, Republic of Korea
| | - Sung Kook Chun
- Department of Brain and Cognitive Sciences, Daegu-Gyeongbuk Institute of Science & Technology (DGIST), Daegu, Republic of Korea; Korea Brain Research Institute (KBRI), Daegu, Republic of Korea
| | - Gi Hoon Son
- Department of Biomedical Sciences, College of Medicine, Korea University, Seoul, Republic of Korea
| | - Kyungjin Kim
- Department of Brain and Cognitive Sciences, Daegu-Gyeongbuk Institute of Science & Technology (DGIST), Daegu, Republic of Korea; Korea Brain Research Institute (KBRI), Daegu, Republic of Korea
| | - Young-Ger Suh
- College of Pharmacy, Cha University, Pochen, Republic of Korea.
| | - Jong-Wha Jung
- College of Pharmacy, Research Institute of Pharmaceutical Sciences, Kyungpook National University, Daegu, Republic of Korea.
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7
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Maltais L, Montagne M, Bédard M, Tremblay C, Soucek L, Lavigne P. Biophysical characterization of the b-HLH-LZ of ΔMax, an alternatively spliced isoform of Max found in tumor cells: Towards the validation of a tumor suppressor role for the Max homodimers. PLoS One 2017; 12:e0174413. [PMID: 28350847 PMCID: PMC5370111 DOI: 10.1371/journal.pone.0174413] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 03/08/2017] [Indexed: 11/19/2022] Open
Abstract
It is classically recognized that the physiological and oncogenic functions of Myc proteins depend on specific DNA binding enabled by the dimerization of its C-terminal basic-region-Helix-Loop-Helix-Leucine Zipper (b-HLH-LZ) domain with that of Max. However, a new paradigm is emerging, where the binding of the c-Myc/Max heterodimer to non-specific sequences in enhancers and promoters drives the transcription of genes involved in diverse oncogenic programs. Importantly, Max can form a stable homodimer even in the presence of c-Myc and bind DNA (specific and non-specific) with comparable affinity to the c-Myc/Max heterodimer. Intriguingly, alterations in the Max gene by germline and somatic mutations or changes in the gene product by alternative splicing (e.g. ΔMax) were recently associated with pheochromocytoma and glioblastoma, respectively. This has led to the proposition that Max is, by itself, a tumor suppressor. However, the actual mechanism through which it exerts such an activity remains to be elucidated. Here, we show that contrary to the WT motif, the b-HLH-LZ of ΔMax does not homodimerize in the absence of DNA. In addition, although ΔMax can still bind the E-box sequence as a homodimer, it cannot bind non-specific DNA in that form, while it can heterodimerize with c-Myc and bind E-box and non-specific DNA as a heterodimer with high affinity. Taken together, our results suggest that the WT Max homodimer is important for attenuating the binding of c-Myc to specific and non-specific DNA, whereas ΔMax is unable to do so. Conversely, the splicing of Max into ΔMax could provoke an increase in overall chromatin bound c-Myc. According to the new emerging paradigm, the splicing event and the stark reduction in homodimer stability and DNA binding should promote tumorigenesis impairing the tumor suppressor activity of the WT homodimer of Max.
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Affiliation(s)
- Loïka Maltais
- Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Institut de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, Québec, Canada
- PROTÉO; Regroupement Stratégique sur la Fonction, la Structure et l'Ingénierie des Protéines, Université Laval, Québec, Canada
| | - Martin Montagne
- Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Institut de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, Québec, Canada
- PROTÉO; Regroupement Stratégique sur la Fonction, la Structure et l'Ingénierie des Protéines, Université Laval, Québec, Canada
| | - Mikaël Bédard
- Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Institut de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, Québec, Canada
- PROTÉO; Regroupement Stratégique sur la Fonction, la Structure et l'Ingénierie des Protéines, Université Laval, Québec, Canada
| | - Cynthia Tremblay
- Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Institut de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, Québec, Canada
- PROTÉO; Regroupement Stratégique sur la Fonction, la Structure et l'Ingénierie des Protéines, Université Laval, Québec, Canada
| | - Laura Soucek
- Vall d’Hebron Institute of Oncology (VHIO), Hospital Vall d’Hebron, Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
- Department of Biochemistry and Molecular Biology, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Pierre Lavigne
- Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Institut de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, Québec, Canada
- PROTÉO; Regroupement Stratégique sur la Fonction, la Structure et l'Ingénierie des Protéines, Université Laval, Québec, Canada
- * E-mail:
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8
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Coria-Lucero CD, Golini RS, Ponce IT, Deyurka N, Anzulovich AC, Delgado SM, Navigatore-Fonzo LS. Rhythmic Bdnf and TrkB expression patterns in the prefrontal cortex are lost in aged rats. Brain Res 2016; 1653:51-58. [PMID: 27771283 DOI: 10.1016/j.brainres.2016.10.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Revised: 10/10/2016] [Accepted: 10/18/2016] [Indexed: 12/15/2022]
Abstract
Aging brain undergoes several changes leading to a decline in cognitive functions. Memory and learning-related genes such as Creb, Bdnf and its receptor TrkB, are expressed in different brain regions including prefrontal cortex. Those genes' proteins regulate a wide range of functions such as synaptic plasticity and long-term potentiation. In this work, our objectives were: 1) to investigate whether Creb1, Bdnf and TrkB genes display endogenous circadian expression rhythms, in the prefrontal cortex of rats maintained under constant darkness conditions; 2) to study the synchronization of those temporal patterns to the local cellular clock and 3) to evaluate the aging consequences on both cognition-related genes and activating clock transcription factor, BMAL1, rhythms. A bioinformatics analysis revealed clock-responsive (E-box) sites in regulatory regions of Creb1, Bdnf and TrkB genes. Additionally, cAMP response elements (CRE) were found in Bdnf and TrkB promoters. We observed those key cognition-related factors expression oscillates in the rat prefrontal cortex. Creb1 and TrkB mRNAs display a circadian rhythm with their highest levels occurring at the second half of the 24h period. Interestingly, the cosinor analysis revealed a 12-h rhythm of Bdnf transcript levels, with peaks occurring at the second half of the subjective day and night, respectively. As expected, the BMAL1 rhythm's acrophase precedes Creb1 and first Bdnf expression peaks. Noteworthy, Creb1, Bdnf and TrkB expression rhythms are lost in the prefrontal cortex of aged rats, probably, as consequence of the loss of BMAL1 protein circadian rhythm and altered function of the local cellular clock.
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Affiliation(s)
- Cinthia D Coria-Lucero
- Laboratory of Chronobiology, Multidisciplinary Institute of Biological Research-San Luis (IMIBIO-SL), National Council of Science and Technology (CONICET), National University of San Luis (UNSL)., Av Ejército de los Andes N° 950, D5700HHW, San Luis, Argentina
| | - Rebeca S Golini
- Laboratory of Chronobiology, Multidisciplinary Institute of Biological Research-San Luis (IMIBIO-SL), National Council of Science and Technology (CONICET), National University of San Luis (UNSL)., Av Ejército de los Andes N° 950, D5700HHW, San Luis, Argentina
| | - Ivana T Ponce
- Laboratory of Chronobiology, Multidisciplinary Institute of Biological Research-San Luis (IMIBIO-SL), National Council of Science and Technology (CONICET), National University of San Luis (UNSL)., Av Ejército de los Andes N° 950, D5700HHW, San Luis, Argentina
| | - Nicolas Deyurka
- Laboratory of Chronobiology, Multidisciplinary Institute of Biological Research-San Luis (IMIBIO-SL), National Council of Science and Technology (CONICET), National University of San Luis (UNSL)., Av Ejército de los Andes N° 950, D5700HHW, San Luis, Argentina
| | - Ana C Anzulovich
- Laboratory of Chronobiology, Multidisciplinary Institute of Biological Research-San Luis (IMIBIO-SL), National Council of Science and Technology (CONICET), National University of San Luis (UNSL)., Av Ejército de los Andes N° 950, D5700HHW, San Luis, Argentina
| | - Silvia M Delgado
- Laboratory of Chronobiology, Multidisciplinary Institute of Biological Research-San Luis (IMIBIO-SL), National Council of Science and Technology (CONICET), National University of San Luis (UNSL)., Av Ejército de los Andes N° 950, D5700HHW, San Luis, Argentina; Laboratory of Biology Reproduction, Multidisciplinary Institute of Biological Research-San Luis (IMIBIO-SL), National Council of Science and Technology (CONICET), National University of San Luis (UNSL)., Av Ejército de los Andes N° 950, D5700HHW, San Luis, Argentina
| | - Lorena S Navigatore-Fonzo
- Laboratory of Chronobiology, Multidisciplinary Institute of Biological Research-San Luis (IMIBIO-SL), National Council of Science and Technology (CONICET), National University of San Luis (UNSL)., Av Ejército de los Andes N° 950, D5700HHW, San Luis, Argentina.
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9
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Zhou J, Yu W, Hardin PE. CLOCKWORK ORANGE Enhances PERIOD Mediated Rhythms in Transcriptional Repression by Antagonizing E-box Binding by CLOCK-CYCLE. PLoS Genet 2016; 12:e1006430. [PMID: 27814361 PMCID: PMC5096704 DOI: 10.1371/journal.pgen.1006430] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 10/17/2016] [Indexed: 01/13/2023] Open
Abstract
The Drosophila circadian oscillator controls daily rhythms in physiology, metabolism and behavior via transcriptional feedback loops. CLOCK-CYCLE (CLK-CYC) heterodimers initiate feedback loop function by binding E-box elements to activate per and tim transcription. PER-TIM heterodimers then accumulate, bind CLK-CYC to inhibit transcription, and are ultimately degraded to enable the next round of transcription. The timing of transcriptional events in this feedback loop coincide with, and are controlled by, rhythms in CLK-CYC binding to E-boxes. PER rhythmically binds CLK-CYC to initiate transcriptional repression, and subsequently promotes the removal of CLK-CYC from E-boxes. However, little is known about the mechanism by which CLK-CYC is removed from DNA. Previous studies demonstrated that the transcription repressor CLOCKWORK ORANGE (CWO) contributes to core feedback loop function by repressing per and tim transcription in cultured S2 cells and in flies. Here we show that CWO rhythmically binds E-boxes upstream of core clock genes in a reciprocal manner to CLK, thereby promoting PER-dependent removal of CLK-CYC from E-boxes, and maintaining repression until PER is degraded and CLK-CYC displaces CWO from E-boxes to initiate transcription. These results suggest a model in which CWO co-represses CLK-CYC transcriptional activity in conjunction with PER by competing for E-box binding once CLK-CYC-PER complexes have formed. Given that CWO orthologs DEC1 and DEC2 also target E-boxes bound by CLOCK-BMAL1, a similar mechanism may operate in the mammalian clock.
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Affiliation(s)
- Jian Zhou
- Department of Biology, Texas A&M University, College Station, Texas, United States of America
- Center for Biological Clocks Research, Texas A&M University, College Station, Texas, United States of America
| | - Wangjie Yu
- Department of Biology, Texas A&M University, College Station, Texas, United States of America
- Center for Biological Clocks Research, Texas A&M University, College Station, Texas, United States of America
| | - Paul E. Hardin
- Department of Biology, Texas A&M University, College Station, Texas, United States of America
- Center for Biological Clocks Research, Texas A&M University, College Station, Texas, United States of America
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10
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Yang H, Liu T, Wang J, Li TW, Fan W, Peng H, Krishnan A, Gores GJ, Mato JM, Lu SC. Deregulated methionine adenosyltransferase α1, c-Myc, and Maf proteins together promote cholangiocarcinoma growth in mice and humans(‡). Hepatology 2016; 64:439-55. [PMID: 26969892 PMCID: PMC4956551 DOI: 10.1002/hep.28541] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 02/24/2016] [Accepted: 03/02/2016] [Indexed: 12/11/2022]
Abstract
UNLABELLED c-Myc induction drives cholestatic liver injury and cholangiocarcinoma (CCA) in mice, and induction of Maf proteins (MafG and c-Maf) contributes to cholestatic liver injury, whereas S-adenosylmethionine (SAMe) administration is protective. Here, we determined whether there is interplay between c-Myc, Maf proteins, and methionine adenosyltransferase α1 (MATα1), which is responsible for SAMe biosynthesis in the liver. We used bile duct ligation (BDL) and lithocholic acid (LCA) treatment in mice as chronic cholestasis models, a murine CCA model, human CCA cell lines KMCH and Huh-28, human liver cancer HepG2, and human CCA specimens to study gene and protein expression, protein-protein interactions, molecular mechanisms, and functional outcomes. We found that c-Myc, MATα1 (encoded by MAT1A), MafG, and c-Maf interact with one another directly. MAT1A expression fell in hepatocytes and bile duct epithelial cells during chronic cholestasis and in murine and human CCA. The opposite occurred with c-Myc, MafG, and c-Maf expression. MATα1 interacts mainly with Mnt in normal liver, but this switches to c-Maf, MafG, and c-Myc in cholestatic livers and CCA. Promoter regions of these genes have E-boxes that are bound by MATα1 and Mnt in normal liver and benign bile duct epithelial cells that switched to c-Myc, c-Maf, and MafG in cholestasis and CCA cells. E-box positively regulates c-Myc, MafG, and c-Maf, but it negatively regulates MAT1A. MATα1 represses, whereas c-Myc, MafG, and c-Maf enhance, E-box-driven promoter activity. Knocking down MAT1A or overexpressing MafG or c-Maf enhanced CCA growth and invasion in vivo. CONCLUSION There is a novel interplay between MATα1, c-Myc, and Maf proteins, and their deregulation during chronic cholestasis may facilitate CCA oncogenesis. (Hepatology 2016;64:439-455).
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Affiliation(s)
- Heping Yang
- Division of Gastroenterology, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
- USC Research Center for Liver Diseases, Keck School of Medicine USC, Los Angeles, CA 90033, USA
| | - Ting Liu
- Division of Gastroenterology, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
- USC Research Center for Liver Diseases, Keck School of Medicine USC, Los Angeles, CA 90033, USA
- Department of Gastroenterology, Xiangya Hospital Central South University, Changsha, Hunan 410008, China
| | - Jiaohong Wang
- Division of Gastroenterology, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
- USC Research Center for Liver Diseases, Keck School of Medicine USC, Los Angeles, CA 90033, USA
| | - Tony W.H. Li
- Division of Gastroenterology, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
- USC Research Center for Liver Diseases, Keck School of Medicine USC, Los Angeles, CA 90033, USA
| | - Wei Fan
- Division of Gastroenterology, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
- USC Research Center for Liver Diseases, Keck School of Medicine USC, Los Angeles, CA 90033, USA
- Department of Geriatrics, Guangzhou First People’s Hospital, Guangzhou 510180, China
| | - Hui Peng
- Division of Gastroenterology, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
- USC Research Center for Liver Diseases, Keck School of Medicine USC, Los Angeles, CA 90033, USA
| | - Anuradha Krishnan
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN
| | - Gregory J. Gores
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN
| | - Jose M. Mato
- CIC bioGUNE, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (Ciberehd), Technology, Park of Bizkaia, 48160 Derio, Bizkaia, Spain
| | - Shelly C. Lu
- Division of Gastroenterology, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
- USC Research Center for Liver Diseases, Keck School of Medicine USC, Los Angeles, CA 90033, USA
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Shi G, Xie P, Qu Z, Zhang Z, Dong Z, An Y, Xing L, Liu Z, Dong Y, Xu G, Yang L, Liu Y, Xu Y. Distinct Roles of HDAC3 in the Core Circadian Negative Feedback Loop Are Critical for Clock Function. Cell Rep 2016; 14:823-834. [PMID: 26776516 DOI: 10.1016/j.celrep.2015.12.076] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 10/11/2015] [Accepted: 12/15/2015] [Indexed: 01/30/2023] Open
Abstract
In the core mammalian circadian negative feedback loop, the BMAL1-CLOCK complex activates the transcription of the genes Period (Per) and Cryptochrome (Cry). To close the negative feedback loop, the PER-CRY complex interacts with the BMAL1-CLOCK complex to repress its activity. These two processes are separated temporally to ensure clock function. Here, we show that histone deacetylase 3 (HDAC3) is a critical component of the circadian negative feedback loop by regulating both the activation and repression processes in a deacetylase activity-independent manner. Genetic depletion of Hdac3 results in low-amplitude circadian rhythms and dampened E-box-driven transcription. In subjective morning, HDAC3 is required for the efficient transcriptional activation process by regulating BMAL1 stability. In subjective night, however, HDAC3 blocks FBXL3-mediated CRY1 degradation and strongly promotes BMAL1 and CRY1 association. Therefore, these two opposing but temporally separated roles of HDAC3 in the negative feedback loop provide a mechanism for robust circadian gene expression.
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Affiliation(s)
- Guangsen Shi
- Ministry of Education Key Laboratory of Model Animals for Disease Study, Model Animal Research Center, Nanjing University, 12 Xuefu Road, Pukou District, Nanjing 210061, China
| | - Pancheng Xie
- Ministry of Education Key Laboratory of Model Animals for Disease Study, Model Animal Research Center, Nanjing University, 12 Xuefu Road, Pukou District, Nanjing 210061, China
| | - Zhipeng Qu
- Ministry of Education Key Laboratory of Model Animals for Disease Study, Model Animal Research Center, Nanjing University, 12 Xuefu Road, Pukou District, Nanjing 210061, China
| | - Zhihui Zhang
- Ministry of Education Key Laboratory of Model Animals for Disease Study, Model Animal Research Center, Nanjing University, 12 Xuefu Road, Pukou District, Nanjing 210061, China
| | - Zhen Dong
- Ministry of Education Key Laboratory of Model Animals for Disease Study, Model Animal Research Center, Nanjing University, 12 Xuefu Road, Pukou District, Nanjing 210061, China
| | - Yang An
- Ministry of Education Key Laboratory of Model Animals for Disease Study, Model Animal Research Center, Nanjing University, 12 Xuefu Road, Pukou District, Nanjing 210061, China
| | - Lijuan Xing
- Cambridge-Suda Genomic Research Center, Soochow University, 199 Renai Road, Suzhou 215123, China
| | - Zhiwei Liu
- Cambridge-Suda Genomic Research Center, Soochow University, 199 Renai Road, Suzhou 215123, China
| | - Yingying Dong
- Cambridge-Suda Genomic Research Center, Soochow University, 199 Renai Road, Suzhou 215123, China
| | - Guoqiang Xu
- College of Pharmaceutical Sciences, Soochow University, 199 Renai Road, Suzhou 215123, China
| | - Ling Yang
- Cambridge-Suda Genomic Research Center, Soochow University, 199 Renai Road, Suzhou 215123, China
| | - Yi Liu
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
| | - Ying Xu
- Ministry of Education Key Laboratory of Model Animals for Disease Study, Model Animal Research Center, Nanjing University, 12 Xuefu Road, Pukou District, Nanjing 210061, China; Cambridge-Suda Genomic Research Center, Soochow University, 199 Renai Road, Suzhou 215123, China; Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai 200433, China.
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12
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Luo W, Li E, Nie Q, Zhang X. Myomaker, Regulated by MYOD, MYOG and miR-140-3p, Promotes Chicken Myoblast Fusion. Int J Mol Sci 2015; 16:26186-201. [PMID: 26540045 PMCID: PMC4661805 DOI: 10.3390/ijms161125946] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2015] [Revised: 10/16/2015] [Accepted: 10/22/2015] [Indexed: 12/21/2022] Open
Abstract
The fusion of myoblasts is an important step during skeletal muscle differentiation. A recent study in mice found that a transmembrane protein called Myomaker, which is specifically expressed in muscle, is critical for myoblast fusion. However, the cellular mechanism of its roles and the regulatory mechanism of its expression remain unclear. Chicken not only plays an important role in meat production but is also an ideal model organism for muscle development research. Here, we report that Myomaker is also essential for chicken myoblast fusion. Forced expression of Myomaker in chicken primary myoblasts promotes myoblast fusion, whereas knockdown of Myomaker by siRNA inhibits myoblast fusion. MYOD and MYOG, which belong to the family of myogenic regulatory factors, can bind to a conserved E-box located proximal to the Myomaker transcription start site and induce Myomaker transcription. Additionally, miR-140-3p can inhibit Myomaker expression and myoblast fusion, at least in part, by binding to the 3ʹ UTR of Myomaker in vitro. These findings confirm the essential roles of Myomaker in avian myoblast fusion and show that MYOD, MYOG and miR-140-3p can regulate Myomaker expression.
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Affiliation(s)
- Wen Luo
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou 510642, China.
- Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, South China Agricultural University, Guangzhou 510642, China.
- Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, South China Agricultural University, Guangzhou 510642, China.
| | - Erxin Li
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou 510642, China.
- Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, South China Agricultural University, Guangzhou 510642, China.
- Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, South China Agricultural University, Guangzhou 510642, China.
| | - Qinghua Nie
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou 510642, China.
- Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, South China Agricultural University, Guangzhou 510642, China.
- Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, South China Agricultural University, Guangzhou 510642, China.
| | - Xiquan Zhang
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou 510642, China.
- Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, South China Agricultural University, Guangzhou 510642, China.
- Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, South China Agricultural University, Guangzhou 510642, China.
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13
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Evans L, Chen L, Milazzo G, Gherardi S, Perini G, Willmore E, Newell DR, Tweddle DA. SKP2 is a direct transcriptional target of MYCN and a potential therapeutic target in neuroblastoma. Cancer Lett 2015; 363:37-45. [PMID: 25843293 DOI: 10.1016/j.canlet.2015.03.044] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 03/26/2015] [Accepted: 03/28/2015] [Indexed: 12/13/2022]
Abstract
SKP2 is the substrate recognition subunit of the ubiquitin ligase complex which targets p27(KIP1) for degradation. Induced at the G1/S transit of the cell cycle, SKP2 is frequently overexpressed in human cancers and contributes to malignancy. We previously identified SKP2 as a possible MYCN target gene and hence hypothesise that SKP2 is a potential therapeutic target in MYCN amplified disease. A positive correlation was identified between MYCN activity and SKP2 mRNA expression in Tet21N MYCN-regulatable cells and a panel of MYCN amplified and non-amplified neuroblastoma cell lines. In chromatin immunoprecipitation and reporter gene assays, MYCN bound directly to E-boxes within the SKP2 promoter and induced transcriptional activity which was decreased by the removal of MYCN and E-box mutation. Although SKP2 knockdown inhibited cell growth in both MYCN amplified and non-amplified cells, cell cycle arrest and apoptosis were induced only in non-MYCN amplified neuroblastoma cells. In conclusion these data identify SKP2 as a direct transcriptional target of MYCN and supports SKP2 as a potential therapeutic target in neuroblastoma.
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Affiliation(s)
- Laura Evans
- Newcastle Cancer Centre at the Northern Institute for Cancer Research, Newcastle University, Newcastle Upon Tyne NE2 4HH, UK
| | - Lindi Chen
- Newcastle Cancer Centre at the Northern Institute for Cancer Research, Newcastle University, Newcastle Upon Tyne NE2 4HH, UK
| | - Giorgio Milazzo
- Department of Pharmacy and Biotechnology, University of Bologna, Via F. Selmi 3, Bologna 40126, Italy
| | - Samuele Gherardi
- Department of Pharmacy and Biotechnology, University of Bologna, Via F. Selmi 3, Bologna 40126, Italy; Health Science and Technologies-Interdepartmental Centre for Industrial Research (HST-ICIR), University of Bologna, Via Tolara di Sopra 41/E, Ozzano Emilia (Bologna) 40064, Italy
| | - Giovanni Perini
- Department of Pharmacy and Biotechnology, University of Bologna, Via F. Selmi 3, Bologna 40126, Italy; Health Science and Technologies-Interdepartmental Centre for Industrial Research (HST-ICIR), University of Bologna, Via Tolara di Sopra 41/E, Ozzano Emilia (Bologna) 40064, Italy
| | - Elaine Willmore
- Newcastle Cancer Centre at the Northern Institute for Cancer Research, Newcastle University, Newcastle Upon Tyne NE2 4HH, UK
| | - David R Newell
- Newcastle Cancer Centre at the Northern Institute for Cancer Research, Newcastle University, Newcastle Upon Tyne NE2 4HH, UK
| | - Deborah A Tweddle
- Newcastle Cancer Centre at the Northern Institute for Cancer Research, Newcastle University, Newcastle Upon Tyne NE2 4HH, UK.
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14
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Cui Y, Sui Y, Xu J, Zhu F, Palli SR. Juvenile hormone regulates Aedes aegypti Krüppel homolog 1 through a conserved E box motif. Insect Biochem Mol Biol 2014; 52:23-32. [PMID: 24931431 PMCID: PMC4143451 DOI: 10.1016/j.ibmb.2014.05.009] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 05/16/2014] [Accepted: 05/28/2014] [Indexed: 05/19/2023]
Abstract
Juvenile hormone (JH) plays important roles in regulation of many physiological processes including development, reproduction and metabolism in insects. However, the molecular mechanisms of JH signaling pathway are not completely understood. To elucidate the molecular mechanisms of JH regulation of Krüppel homolog 1 gene (Kr-h1) in Aedes aegypti, we employed JH-sensitive Aag-2 cells developed from the embryos of this insect. In Aag-2 cells, AaKr-h1 gene is induced by nanomolar concentration of JH III, its expression peaked at 1.5 h after treatment with JH III. RNAi studies showed that JH induction of this gene requires the presence of Ae. aegypti methoprene-tolerant (AaMet). A conserved 13 nucleotide JH response element (JHRE, TGCCTCCACGTGC) containing canonical E box motif (underlined) identified in the promoter of AaKr-h1 is required for JH induction of this gene. Critical nucleotides in the JHRE required for JH action were identified by employing mutagenesis and reporter assays. Reporter assays also showed that basic helix loop helix (bHLH) domain of AaMet is required for JH induction of AaKr-h1. 5' rapid amplification of cDNA ends method identified two isoforms of AaKr-h1, AaKr-h1α and AaKr-h1β, the expression of both isoforms is induced by JH III, but AaKr-h1α is the predominant isoform in both Aag-2 cells and Ae. aegypti larvae.
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Affiliation(s)
- Yingjun Cui
- Department of Entomology, College of Agriculture, University of Kentucky, Lexington, KY 40546, United States
| | - Yipeng Sui
- Department of Entomology, College of Agriculture, University of Kentucky, Lexington, KY 40546, United States
| | - Jingjing Xu
- Department of Entomology, College of Agriculture, University of Kentucky, Lexington, KY 40546, United States
| | - Fang Zhu
- Department of Entomology, College of Agriculture, University of Kentucky, Lexington, KY 40546, United States
| | - Subba Reddy Palli
- Department of Entomology, College of Agriculture, University of Kentucky, Lexington, KY 40546, United States.
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15
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Gesell A, Yoshida K, Tran LT, Constabel CP. Characterization of an apple TT2-type R2R3 MYB transcription factor functionally similar to the poplar proanthocyanidin regulator PtMYB134. Planta 2014; 240:497-511. [PMID: 24923676 DOI: 10.1007/s00425-014-2098-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Accepted: 05/19/2014] [Indexed: 05/06/2023]
Abstract
The apple MdMYB9 gene encodes a positive regulator of proanthocyanidin synthesis that activates anthocyanidin reductase promoters from apple and poplar via interaction with basic helix-loop-helix proteins. The regulation of proanthocyanidins (PAs, condensed tannins) is of great importance in food plants due to the many benefits of PAs in the human diet. Two candidate flavonoid MYB regulators, MdMYB9 and MdMYB11, were cloned from apple (Malus × domestica) based on their similarity to known MYB PA regulators. Transcript accumulation of both MdMYB9 and MdMYB11 was induced by high light and wounding, similar to the poplar (Populus spp) PA regulator PtMYB134. In transient activation assays with various basic helix-loop-helix (bHLH) co-regulators, MdMYB9 activated apple and poplar anthocyanidin reductase (ANR) promoters, while MdMYB11 showed no activity. Potential transcription factor binding elements were found within several ANR promoters, and the importance of the bHLH binding site (E-box) on ANR promoter activation was demonstrated via mutational analysis. The ability of MdMYB9 and PtMYB134 to reciprocally activate ANR promoters from both apple and poplar and to partner with heterologous bHLH co-factors from these plants confirms the high degree of conservation of PA regulatory complexes across species. The similarity in apple and poplar PA regulation suggests that regulatory genes from poplar could be effectively employed for metabolic engineering of the PA pathway in apple.
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Affiliation(s)
- Andreas Gesell
- Department of Biology & Centre for Forest Biology, University of Victoria, Station CSC, Box 3020, Victoria, BC, V8W 3N5, Canada
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16
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Zhao Y, Cheng D, Wang S, Zhu J. Dual roles of c-Myc in the regulation of hTERT gene. Nucleic Acids Res 2014; 42:10385-98. [PMID: 25170084 PMCID: PMC4176324 DOI: 10.1093/nar/gku721] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2014] [Revised: 07/24/2014] [Accepted: 07/25/2014] [Indexed: 12/04/2022] Open
Abstract
Human telomerase gene hTERT is important for cancer and aging. hTERT promoter is regulated by multiple transcription factors (TFs) and its activity is dependent on the chromatin environment. However, it remains unsolved how the interplay between TFs and chromatin environment controls hTERT transcription. In this study, we employed the recombinase-mediated BAC targeting and BAC recombineering techniques to dissect the functions of two proximal E-box sites at -165 and +44 nt in regulating the hTERT promoter in the native genomic contexts. Our data showed that mutations of these sites abolished promoter binding by c-Myc/Max, USF1 and USF2, decreased hTERT promoter activity, and prevented its activation by overexpressed c-Myc. Upon inhibition of histone deacetylases, mutant and wildtype promoters were induced to the same level, indicating that the E-boxes functioned to de-repress the hTERT promoter and allowed its transcription in a repressive chromatin environment. Unexpectedly, knockdown of endogenous c-Myc/Max proteins activated hTERT promoter. This activation did not require the proximal E-boxes but was accompanied by increased promoter accessibility, as indicated by augmented active histone marks and binding of multiple TFs at the promoter. Our studies demonstrated that c-Myc/Max functioned in maintaining chromatin-dependent repression of the hTERT gene in addition to activating its promoter.
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Affiliation(s)
- Yuanjun Zhao
- Department of C & M Physiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA
| | - De Cheng
- Department of C & M Physiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA Department of Pharmaceutical Sciences, Washington State University College of Pharmacy, Spokane, Washington, USA
| | - Shuwen Wang
- Department of C & M Physiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA Department of Pharmaceutical Sciences, Washington State University College of Pharmacy, Spokane, Washington, USA
| | - Jiyue Zhu
- Department of C & M Physiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA Department of Pharmaceutical Sciences, Washington State University College of Pharmacy, Spokane, Washington, USA
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17
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Shin HY, You MK, Jeung JU, Shin JS. OsMPK3 is a TEY-type rice MAPK in Group C and phosphorylates OsbHLH65, a transcription factor binding to the E-box element. Plant Cell Rep 2014; 33:1343-53. [PMID: 24777821 DOI: 10.1007/s00299-014-1620-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 04/01/2014] [Accepted: 04/09/2014] [Indexed: 05/27/2023]
Abstract
OsMPK3 is a TEY-type rice MAPK belonging to Group C and directly phosphorylates OsbHLH65 in the nucleus. OsMPK3 and OsbHLH65 are induced by biotic stress and defense-related hormones. Mitogen-activated protein kinases (MAPKs) are involved in the majority of signaling pathways that regulate plant development and stress tolerance via the phosphorylation of target molecules. Plant MAPKs are classified into two subtypes, TEY and TDY, according to the TxY (x = E or D) motif in their activation loop, and the TDY motif is unique to plant MAPKs. In rice, 17 MAPKs have been classified into six groups. To date, the functions of many TDY-type rice MAPKs have been characterized, but little is known of the TEY-type MAPKs in Group C and their possible target substrates. In the study reported here, we determined that a TEY-type rice MAPK belonging to subgroup C, named OsMPK3, phosphorylates its substrate OsbHLH65 in the nucleus. Our electrophoresis mobility shift assay results revealed that OsbHLH65 specifically binds to the E-box cis-element, but not to the G-box. Both OsMPK3 and OsbHLH65 were induced by treatments with rice blast (Magnaporthe grisea), brown planthopper (Nilaparvata lugens), and defense-related hormones, such as methyl jasmonic acid and salicylic acid. Our results suggest the possibility that OsMPK3 contributes to the defense signal transduction by phosphorylating the basic helix-loop-helix transcription factor.
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Affiliation(s)
- Hyun-Young Shin
- Division of Life Sciences, Korea University, Seoul, 136-701, Korea
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18
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Toyoda S, Yoshimura T, Mizuta J, Miyazaki JI. Auto-regulation of the Sohlh1 gene by the SOHLH2/SOHLH1/SP1 complex: implications for early spermatogenesis and oogenesis. PLoS One 2014; 9:e101681. [PMID: 25003626 PMCID: PMC4086951 DOI: 10.1371/journal.pone.0101681] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Accepted: 06/11/2014] [Indexed: 11/18/2022] Open
Abstract
Tissue-specific basic helix-loop-helix (bHLH) transcription factor proteins often play essential roles in cellular differentiation. The bHLH proteins SOHLH2 and SOHLH1 are expressed specifically in spermatogonia and oocytes and are required for early spermatogonial and oocyte differentiation. We previously reported that knocking out Sohlh2 causes defects in spermatogenesis and oogenesis similar to those in Sohlh1-null mice, and that Sohlh1 is downregulated in the gonads of Sohlh2-null mice. We also demonstrated that SOHLH2 and SOHLH1 can form a heterodimer. These observations led us to hypothesize that the SOHLH2/SOHLH1 heterodimer regulates the Sohlh1 promoter. Here, we show that SOHLH2 and SOHLH1 synergistically upregulate the Sohlh1 gene through E-boxes upstream of the Sohlh1 promoter. Interestingly, we identified an SP1-binding sequence, called a GC-box, adjacent to these E-boxes, and found that SOHLH1 could bind to SP1. Furthermore, chromatin-immunoprecipitation analysis using testes from mice on postnatal day 8 showed that SOHLH1 and SP1 bind to the Sohlh1 promoter region in vivo. Our findings suggest that an SOHLH2/SOHLH1/SP1 ternary complex autonomously and cooperatively regulates Sohlh1 gene transcription through juxtaposed E- and GC-boxes during early spermatogenesis and oogenesis.
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Affiliation(s)
- Shuichi Toyoda
- Division of Stem Cell Regulation Research, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Takuji Yoshimura
- Division of Stem Cell Regulation Research, Osaka University Graduate School of Medicine, Osaka, Japan
- Laboratory of Reproductive Engineering, the Institute of Experimental Animal Sciences, Osaka University Medical School, Osaka, Japan
| | - Junya Mizuta
- Division of Stem Cell Regulation Research, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Jun-ichi Miyazaki
- Division of Stem Cell Regulation Research, Osaka University Graduate School of Medicine, Osaka, Japan
- * E-mail:
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19
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Oh-oka K, Kono H, Ishimaru K, Miyake K, Kubota T, Ogawa H, Okumura K, Shibata S, Nakao A. Expressions of tight junction proteins Occludin and Claudin-1 are under the circadian control in the mouse large intestine: implications in intestinal permeability and susceptibility to colitis. PLoS One 2014; 9:e98016. [PMID: 24845399 PMCID: PMC4028230 DOI: 10.1371/journal.pone.0098016] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2013] [Accepted: 04/27/2014] [Indexed: 12/23/2022] Open
Abstract
Background & Aims The circadian clock drives daily rhythms in behavior and physiology. A recent study suggests that intestinal permeability is also under control of the circadian clock. However, the precise mechanisms remain largely unknown. Because intestinal permeability depends on tight junction (TJ) that regulates the epithelial paracellular pathway, this study investigated whether the circadian clock regulates the expression levels of TJ proteins in the intestine. Methods The expression levels of TJ proteins in the large intestinal epithelium and colonic permeability were analyzed every 4, 6, or 12 hours between wild-type mice and mice with a mutation of a key clock gene Period2 (Per2; mPer2m/m). In addition, the susceptibility to dextran sodium sulfate (DSS)-induced colitis was compared between wild-type mice and mPer2m/m mice. Results The mRNA and protein expression levels of Occludin and Claudin-1 exhibited daily variations in the colonic epithelium in wild-type mice, whereas they were constitutively high in mPer2m/m mice. Colonic permeability in wild-type mice exhibited daily variations, which was inversely associated with the expression levels of Occludin and Claudin-1 proteins, whereas it was constitutively low in mPer2m/m mice. mPer2m/m mice were more resistant to the colonic injury induced by DSS than wild-type mice. Conclusions Occludin and Claudin-1 expressions in the large intestine are under the circadian control, which is associated with temporal regulation of colonic permeability and also susceptibility to colitis.
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Affiliation(s)
- Kyoko Oh-oka
- Department of Immunology, University of Yamanashi Faculty of Medicine, Yamanashi, Japan
| | - Hiroshi Kono
- The First Department of Surgery, University of Yamanashi Faculty of Medicine, Yamanashi, Japan
| | - Kayoko Ishimaru
- Department of Immunology, University of Yamanashi Faculty of Medicine, Yamanashi, Japan
| | - Kunio Miyake
- Department of Epigenetic Medicine, University of Yamanashi Faculty of Medicine, Yamanashi, Japan
| | - Takeo Kubota
- Department of Epigenetic Medicine, University of Yamanashi Faculty of Medicine, Yamanashi, Japan
| | - Hideoki Ogawa
- Atopy Research Center, Juntendo University School of Medicine, Tokyo, Japan
| | - Ko Okumura
- Atopy Research Center, Juntendo University School of Medicine, Tokyo, Japan
| | - Shigenobu Shibata
- Department of Physiology and Pharmacology, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan
| | - Atsuhito Nakao
- Department of Immunology, University of Yamanashi Faculty of Medicine, Yamanashi, Japan
- Atopy Research Center, Juntendo University School of Medicine, Tokyo, Japan
- * E-mail:
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20
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Abstract
Gastrin and its precursors act as growth factors for the normal and neoplastic gastrointestinal mucosa. As the hypoxia mimetic cobalt chloride upregulates the gastrin gene, the effect of other metal ions on gastrin promoter activity was investigated. Gastrin mRNA was measured by real-time PCR, gastrin peptides by RIA, and gastrin promoter activity by dual-luciferase reporter assay. Exposure to Zn(2)(+) ions increased gastrin mRNA concentrations in the human gastric adenocarcinoma cell line AGS in a dose-dependent manner, with a maximum stimulation of 55 ± 14-fold at 100 μM (P<0.05). Significant stimulation was also observed with Cd(2)(+) and Cu(2)(+), but not with Ca(2)(+), Mg(2)(+), Ni(2)(+), or Fe(3)(+) ions. Activation of MAPK and phosphatidylinositol 3-kinase pathways is necessary but not sufficient for gastrin induction by Zn(2)(+). Deletional mutation of the gastrin promoter identified an 11 bp DNA sequence, which contained an E-box motif, as necessary for Zn(2)(+)-dependent gastrin induction. The fact that E-box binding transcription factors play a crucial role in the epithelial-mesenchymal transition (EMT), together with our observation that Zn(2)(+) ions upregulate the gastrin gene in AGS cells by an E-box-dependent mechanism, suggests that Zn(2)(+) ions may induce an EMT, and that gastrin may be involved in the transition.
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Affiliation(s)
- Lin Xiao
- Department of Surgery, Austin Health, The University of Melbourne, Studley Road, Heidelberg, Victoria 3084, Australia
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21
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Guo J, Li T, Schipper J, Nilson KA, Fordjour FK, Cooper JJ, Gordân R, Price DH. Sequence specificity incompletely defines the genome-wide occupancy of Myc. Genome Biol 2014; 15:482. [PMID: 25287278 PMCID: PMC4242493 DOI: 10.1186/s13059-014-0482-3] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Accepted: 09/22/2014] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND The Myc-Max heterodimer is a transcription factor that regulates expression of a large number of genes. Genome occupancy of Myc-Max is thought to be driven by Enhancer box (E-box) DNA elements, CACGTG or variants, to which the heterodimer binds in vitro. RESULTS By analyzing ChIP-Seq datasets, we demonstrate that the positions occupied by Myc-Max across the human genome correlate with the RNA polymerase II, Pol II, transcription machinery significantly better than with E-boxes. Metagene analyses show that in promoter regions, Myc is uniformly positioned about 100 bp upstream of essentially all promoter proximal paused polymerases with Max about 15 bp upstream of Myc. We re-evaluate the DNA binding properties of full length Myc-Max proteins. Electrophoretic mobility shift assay results demonstrate Myc-Max heterodimers display significant sequence preference, but have high affinity for any DNA. Quantification of the relative affinities of Myc-Max for all possible 8-mers using universal protein-binding microarray assays shows that sequences surrounding core 6-mers significantly affect binding. Compared to the in vitro sequence preferences,Myc-Max genomic occupancy measured by ChIP-Seq is largely, although not completely, independent of sequence specificity. CONCLUSIONS We quantified the affinity of Myc-Max to all possible 8-mers and compared this with the sites of Myc binding across the human genome. Our results indicate that the genomic occupancy of Myc cannot be explained by its intrinsic DNA specificity and suggest that the transcription machinery and associated promoter accessibility play a predominant role in Myc recruitment.
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Affiliation(s)
- Jiannan Guo
- />Department of Biochemistry, University of Iowa, Iowa City, IA 52242 USA
| | - Tiandao Li
- />Department of Biochemistry, University of Iowa, Iowa City, IA 52242 USA
- />The Genome Institute, Washington University in St. Louis, St. Louis, MO 63108 USA
| | - Joshua Schipper
- />Institute for Genome Sciences and Policy, Duke University, Durham, NC 27708 USA
| | - Kyle A Nilson
- />Molecular and Cellular Biology Program, University of Iowa, Iowa City, IA 52242 USA
| | - Francis K Fordjour
- />Department of Biochemistry, University of Iowa, Iowa City, IA 52242 USA
| | - Jeffrey J Cooper
- />Department of Biochemistry, University of Iowa, Iowa City, IA 52242 USA
| | - Raluca Gordân
- />Institute for Genome Sciences and Policy, Duke University, Durham, NC 27708 USA
| | - David H Price
- />Department of Biochemistry, University of Iowa, Iowa City, IA 52242 USA
- />Molecular and Cellular Biology Program, University of Iowa, Iowa City, IA 52242 USA
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22
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Ju SY, Chiou SH, Su Y. Maintenance of the stemness in CD44(+) HCT-15 and HCT-116 human colon cancer cells requires miR-203 suppression. Stem Cell Res 2013; 12:86-100. [PMID: 24145190 DOI: 10.1016/j.scr.2013.09.011] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2013] [Revised: 08/21/2013] [Accepted: 09/23/2013] [Indexed: 12/14/2022] Open
Abstract
The purpose of this study was to isolate cancer stem cells (CSCs, also called tumor-initiating cells, TICs) from established human colorectal carcinoma (CRC) cell lines, characterize them extensively and dissect the mechanism for their stemness. Freshly isolated CD44(+) and CD44(-) cells from the HCT-15 human colon cancer cell line were subjected to various analyses. Interestingly, CD44(+) cells exhibited higher soft agar colony-forming ability and in vivo tumorigenicity than CD44(-) cells. In addition, the significant upregulation of the protein Snail and the downregulation of miR-203, a stemness inhibitor, in CD44(+) cells suggested that this population possessed higher invasion/metastasis and differentiation potential than CD44(-) cells. By manipulating the expression of CD44 in HCT-15 and HCT-116 cells, we found that the levels of several EMT activators and miR-203 were positively and negatively correlated with those of CD44, respectively. Further analyses revealed that miR-203 levels were repressed by Snail, which was shown to bind to specific E-box(es) present in the miR-203 promoter. In agreement, silencing miR-203 expression in wild-type HCT-116 human colon cancer cells also resulted in an increase of their stemness. Finally, we discovered that c-Src kinase activity was required for the downregulation of miR-203 in HCT-15 cells, which was stimulated by the interaction between hyaluronan (HA) and CD44. Taken together, CD44 is a critical molecule for modulating stemness in CSCs. More importantly, we show for the first time that the downregulation of miR-203 by HA/CD44 signaling is the main reason for stemness-maintenance in colon cancer cells.
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Affiliation(s)
- Sy-Yeuan Ju
- Institute of Biopharmaceutical Sciences, National Yang-Ming University, Taiwan
| | - Shih-Hwa Chiou
- Institute of Pharmacology, National Yang-Ming University, Taiwan; Department of Medical Research and Education, Taipei Veterans General Hospital, Taipei, Taiwan.
| | - Yeu Su
- Institute of Biopharmaceutical Sciences, National Yang-Ming University, Taiwan.
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23
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Cheon S, Park N, Cho S, Kim K. Glucocorticoid-mediated Period2 induction delays the phase of circadian rhythm. Nucleic Acids Res 2013; 41:6161-74. [PMID: 23620290 PMCID: PMC3695510 DOI: 10.1093/nar/gkt307] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Revised: 04/02/2013] [Accepted: 04/03/2013] [Indexed: 11/21/2022] Open
Abstract
Glucocorticoid (GC) signaling synchronizes the circadian rhythm of individual peripheral cells and induces the expression of circadian genes, including Period1 (Per1) and Period2 (Per2). However, no GC response element (GRE) has been reported in the Per2 promoter region. Here we report the molecular mechanisms of Per2 induction by GC signaling and its relevance to the regulation of circadian timing. We found that GC prominently induced Per2 expression and delayed the circadian phase. The overlapping GRE and E-box (GE2) region in the proximal Per2 promoter was responsible for GC-mediated Per2 induction. The GRE in the Per2 promoter was unique in that brain and muscle ARNT-like protein-1 (BMAL1) was essential for GC-induced Per2 expression, whereas other GRE-containing promoters, such as Per1 and mouse mammary tumor virus, responded to dexamethasone in the absence of BMAL1. This specialized regulatory mechanism was mediated by BMAL1-dependent binding of the GC receptor to GRE in Per2 promoter. When Per2 induction was abrogated by the mutation of the GRE or E-box, the circadian oscillation phase failed to be delayed compared with that of the wild-type. Therefore, the current study demonstrates that the rapid Per2 induction mediated by GC is crucial for delaying the circadian rhythm.
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Affiliation(s)
- Solmi Cheon
- Interdisciplinary Program in Neuroscience, Seoul National University, Seoul 151-742, Korea, Brain Research Center for the 21st Century Frontier R&D Program in Neuroscience, Seoul 151-742, Korea, Department of Biological Sciences, Seoul National University, Seoul 151-742, Korea and Department of Physiology, Neurodegeneration Control Research Center, Kyung Hee University School of Medicine, Seoul 130-701, Korea
| | - Noheon Park
- Interdisciplinary Program in Neuroscience, Seoul National University, Seoul 151-742, Korea, Brain Research Center for the 21st Century Frontier R&D Program in Neuroscience, Seoul 151-742, Korea, Department of Biological Sciences, Seoul National University, Seoul 151-742, Korea and Department of Physiology, Neurodegeneration Control Research Center, Kyung Hee University School of Medicine, Seoul 130-701, Korea
| | - Sehyung Cho
- Interdisciplinary Program in Neuroscience, Seoul National University, Seoul 151-742, Korea, Brain Research Center for the 21st Century Frontier R&D Program in Neuroscience, Seoul 151-742, Korea, Department of Biological Sciences, Seoul National University, Seoul 151-742, Korea and Department of Physiology, Neurodegeneration Control Research Center, Kyung Hee University School of Medicine, Seoul 130-701, Korea
| | - Kyungjin Kim
- Interdisciplinary Program in Neuroscience, Seoul National University, Seoul 151-742, Korea, Brain Research Center for the 21st Century Frontier R&D Program in Neuroscience, Seoul 151-742, Korea, Department of Biological Sciences, Seoul National University, Seoul 151-742, Korea and Department of Physiology, Neurodegeneration Control Research Center, Kyung Hee University School of Medicine, Seoul 130-701, Korea
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24
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Shende VR, Neuendorff N, Earnest DJ. Role of miR-142-3p in the post-transcriptional regulation of the clock gene Bmal1 in the mouse SCN. PLoS One 2013; 8:e65300. [PMID: 23755214 PMCID: PMC3673942 DOI: 10.1371/journal.pone.0065300] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 04/24/2013] [Indexed: 11/30/2022] Open
Abstract
MicroRNAs (miRNAs) are small non-coding RNAs that function as post-transcriptional modulators by regulating stability or translation of target mRNAs. Recent studies have implicated miRNAs in the regulation of mammalian circadian rhythms. To explore the role of miRNAs in the post-transcriptional modulation of core clock genes in the master circadian pacemaker, we examined miR-142-3p for evidence of circadian expression in the suprachiasmatic nuclei (SCN), regulation of its putative clock gene target Bmal1 via specific binding sites in the 3' UTR and overexpression-induced changes in the circadian rhythm of BMAL1 protein levels in SCN cells. In mice exposed to constant darkness (DD), miR-142-3p levels in the SCN were characterized by circadian rhythmicity with peak expression during early subjective day at CT 3. Mutagenesis studies indicate that two independent miRNA recognition elements located at nucleotides 1-7 and 335-357 contribute equally to miR-142-3p-induced repression of luciferase-reported Bmal1 3' UTR activity. Importantly, overexpression of miR-142-3p in immortalized SCN cells abolished circadian variation in endogenous BMAL1 protein levels in vitro. Collectively, our results suggest that miR-142-3p may play a role in the post-transcriptional modulation of Bmal1 and its oscillatory regulation in molecular feedback loops mediating SCN circadian function.
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Affiliation(s)
- Vikram R. Shende
- Department of Biology, Texas A&M University, College Station, Texas, United States of America
- Center for Biological Clocks Research, Texas A&M University, College Station, Texas, United States of America
| | - Nichole Neuendorff
- Department of Neuroscience and Experimental Therapeutics, Texas A&M Health Science Center, College of Medicine, Bryan, Texas, United States of America
| | - David J. Earnest
- Department of Biology, Texas A&M University, College Station, Texas, United States of America
- Center for Biological Clocks Research, Texas A&M University, College Station, Texas, United States of America
- Department of Neuroscience and Experimental Therapeutics, Texas A&M Health Science Center, College of Medicine, Bryan, Texas, United States of America
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25
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Huang XS, Wang W, Zhang Q, Liu JH. A basic helix-loop-helix transcription factor, PtrbHLH, of Poncirus trifoliata confers cold tolerance and modulates peroxidase-mediated scavenging of hydrogen peroxide. Plant Physiol 2013; 162:1178-94. [PMID: 23624854 PMCID: PMC3668048 DOI: 10.1104/pp.112.210740] [Citation(s) in RCA: 160] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Accepted: 04/24/2013] [Indexed: 05/18/2023]
Abstract
The basic helix-loop-helix (bHLH) transcription factors are involved in a variety of physiological processes. However, plant bHLHs functioning in cold tolerance and the underlying mechanisms remain poorly understood. Here, we report the identification and functional characterization of PtrbHLH isolated from trifoliate orange (Poncirus trifoliata). The transcript levels of PtrbHLH were up-regulated under various abiotic stresses, particularly cold. PtrbHLH was localized in the nucleus with transactivation activity. Overexpression of PtrbHLH in tobacco (Nicotiana tabacum) or lemon (Citrus limon) conferred enhanced tolerance to cold under chilling or freezing temperatures, whereas down-regulation of PtrbHLH in trifoliate orange by RNA interference (RNAi) resulted in elevated cold sensitivity. A range of stress-responsive genes was up-regulated or down-regulated in the transgenic lemon. Of special note, several peroxidase (POD) genes were induced after cold treatment. Compared with the wild type, POD activity was increased in the overexpression plants but decreased in the RNAi plants, which was inversely correlated with the hydrogen peroxide (H2O2) levels in the tested lines. Treatment of the transgenic tobacco plants with POD inhibitors elevated the H2O2 levels and greatly compromised their cold tolerance, while exogenous replenishment of POD enhanced cold tolerance of the RNAi line. In addition, transgenic tobacco and lemon plants were more tolerant to oxidative stresses. Yeast one-hybrid assay and transient expression analysis demonstrated that PtrbHLH could bind to the E-box elements in the promoter region of a POD gene. Taken together, these results demonstrate that PtrbHLH plays an important role in cold tolerance, at least in part, by positively regulating POD-mediated reactive oxygen species removal.
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Affiliation(s)
- Xiao-San Huang
- Key Laboratory of Horticultural Plant Biology of the Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, China
| | - Wei Wang
- Key Laboratory of Horticultural Plant Biology of the Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, China
| | - Qian Zhang
- Key Laboratory of Horticultural Plant Biology of the Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, China
| | - Ji-Hong Liu
- Key Laboratory of Horticultural Plant Biology of the Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, China
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Prokop JW, Liu Y, Milsted A, Peng H, Rauscher FJ. A method for in silico identification of SNAIL/SLUG DNA binding potentials to the E-box sequence using molecular dynamics and evolutionary conserved amino acids. J Mol Model 2013; 19:3463-9. [PMID: 23708613 DOI: 10.1007/s00894-013-1876-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 04/30/2013] [Indexed: 11/25/2022]
Abstract
Binding of transcription factors to DNA is a dynamic process allowing for spatial- and sequence-specificity. Many methods for determination of DNA-protein structures do not allow for identification of dynamics of the search process, but provide only a single snapshot of the most stable binding. In order to better understand the dynamics of DNA binding as a protein encounters its cognate site, we have created a computer-based DNA scanning array macro that sequentially inserts a high affinity DNA consensus binding site at all possible locations in a predicted protein-DNA interface. We show, using short molecular dynamic simulations at each location in the interface, that energy minimized states and decreased movement of evolutionary conserved amino acids can be readily observed and used to predict the consensus binding site. The macro was applied to SNAIL class C2H2 zinc finger family proteins. The analysis suggests that (1) SNAIL binds to the E-box in multiple states during its encounter with its cognate site; (2) several different amino acids contribute to the E-box binding in each state; (3) the linear array of zinc fingers contributes differentially to overall folding and base-pair recognition; and (4) each finger may be specialized for stability and sequence specificity. Moreover, the macromolecular movement observed using this dynamic approach may allow the NH2-terminal finger to bind without sequence specificity yet result in higher binding energy. This macro and overall approach could be applicable to many evolutionary conserved transcription factor families and should help to better elucidate the varied mechanisms used for DNA sequence-specific binding.
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Affiliation(s)
- Jeremy W Prokop
- Program of Integrated Bioscience, The University of Akron, Akron, OH 44325, USA.
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27
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França MM, Ferraz-de-Souza B, Santos MG, Lerario AM, Fragoso MCBV, Latronico AC, Kuick RD, Hammer GD, Lotfi CF. POD-1 binding to the E-box sequence inhibits SF-1 and StAR expression in human adrenocortical tumor cells. Mol Cell Endocrinol 2013; 371:140-7. [PMID: 23313103 PMCID: PMC5749231 DOI: 10.1016/j.mce.2012.12.029] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Revised: 12/21/2012] [Accepted: 12/28/2012] [Indexed: 11/29/2022]
Abstract
Pod-1/Tcf21 is expressed at epithelial-mesenchymal interaction sites during development of many organs. Different approaches have demonstrated that Pod-1 transcriptionally inhibits Sf-1/NR5A1 during gonadal development. Disruption of Sf-1 can lead to disorders of adrenal development, while increased dosage of SF-1 has been related to increased adrenal cell proliferation and tumorigenesis. In this study, we analyzed whether POD-1 overexpression inhibits the endogenous Sf-1 expression in human and mouse adrenocortical tumor cells. Cells were transiently transfected with luciferase reporter gene under the control of Sf-1 promoter and with an expression vector encoding Pod-1. Pod-1 construct inhibited the transcription of the Sf1/Luc reporter gene in a dose-dependent manner in mouse Y-1 adrenocortical carcinoma (ACC) cells, and inhibited endogenous SF-1 expression in the human H295R and ACC-T36 adrenocortical carcinoma cells. These results were validated by chromatin immunoprecipitation assay with POD-1-transfected H295R cells using primers specific to E-box sequence in SF-1 promoter region, indicating that POD-1 binds to the SF-1 E-box promoter. Moreover, POD-1 over-expression resulted in a decrease in expression of the SF-1 target gene, StAR (Steroidogenic Acute Regulatory Protein). Lastly, while the induced expression of POD-1 did not affect the cell viability of H295R/POD-1 or ACC-T36/POD-1 cells, the most significantly enriched KEGG pathways for genes negatively correlated to POD-1/TCF21 in 33 human ACCs were those associated with cell cycle genes.
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Affiliation(s)
- Monica Malheiros França
- Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, SP, Brazil
| | - Bruno Ferraz-de-Souza
- Laboratory of Carbohydrates and Radioimmunoassays (LIM-18), School of Medicine, University of São Paulo, São Paulo 01246-903, SP, Brazil
| | - Mariza Gerdulo Santos
- Laboratory of Hormones and Molecular Genetics (LIM-42), Division of Endocrinology, School of Medicine, University of São Paulo, São Paulo 01246-903, SP, Brazil
| | - Antonio Marcondes Lerario
- Laboratory of Hormones and Molecular Genetics (LIM-42), Division of Endocrinology, School of Medicine, University of São Paulo, São Paulo 01246-903, SP, Brazil
| | - Maria Candida Barisson Villares Fragoso
- Laboratory of Hormones and Molecular Genetics (LIM-42), Division of Endocrinology, School of Medicine, University of São Paulo, São Paulo 01246-903, SP, Brazil
| | - Ana Claudia Latronico
- Laboratory of Hormones and Molecular Genetics (LIM-42), Division of Endocrinology, School of Medicine, University of São Paulo, São Paulo 01246-903, SP, Brazil
| | - Rork D. Kuick
- Biostatistics Core of the Comprehensive Cancer Center, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Gary D. Hammer
- Department of Internal Medicine, Metabolism, Endocrinology and Diabetes, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Claudimara F.P. Lotfi
- Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, SP, Brazil
- Corresponding author. Tel.: +55 11 3091 7492; fax: +55 11 3091 7366. (C.F.P. Lotfi)
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Itoh TQ, Matsumoto A, Tanimura T. C-terminal binding protein (CtBP) activates the expression of E-box clock genes with CLOCK/CYCLE in Drosophila. PLoS One 2013; 8:e63113. [PMID: 23646183 PMCID: PMC3640014 DOI: 10.1371/journal.pone.0063113] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Accepted: 04/02/2013] [Indexed: 12/21/2022] Open
Abstract
In Drosophila, CLOCK/CYCLE heterodimer (CLK/CYC) is the primary activator of circadian clock genes that contain the E-box sequence in their promoter regions (hereafter referred to as "E-box clock genes"). Although extensive studies have investigated the feedback regulation of clock genes, little is known regarding other factors acting with CLK/CYC. Here we show that Drosophila C-terminal binding protein (dCtBP), a transcriptional co-factor, is involved in the regulation of the E-box clock genes. In vivo overexpression of dCtBP in clock cells lengthened or abolished circadian locomotor rhythm with up-regulation of a subset of the E-box clock genes, period (per), vrille (vri), and PAR domain protein 1ε (Pdp1ε). Co-expression of dCtBP with CLK in vitro also increased the promoter activity of per, vri, Pdp1ε and cwo depending on the amount of dCtBP expression, whereas no effect was observed without CLK. The activation of these clock genes in vitro was not observed when we used mutated dCtBP which carries amino acid substitutions in NAD+ domain. These results suggest that dCtBP generally acts as a putative co-activator of CLK/CYC through the E-box sequence.
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Affiliation(s)
- Taichi Q. Itoh
- Graduate School of Systems Life Sciences, Kyushu University, Hakozaki, Fukuoka, Japan
| | - Akira Matsumoto
- Department of Biology, Juntendo University School of Medicine, Inba-gun, Chiba, Japan
| | - Teiichi Tanimura
- Graduate School of Systems Life Sciences, Kyushu University, Hakozaki, Fukuoka, Japan
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29
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Shimomura K, Kumar V, Koike N, Kim TK, Chong J, Buhr ED, Whiteley AR, Low SS, Omura C, Fenner D, Owens JR, Richards M, Yoo SH, Hong HK, Vitaterna MH, Bass J, Pletcher MT, Wiltshire T, Hogenesch J, Lowrey PL, Takahashi JS. Usf1, a suppressor of the circadian Clock mutant, reveals the nature of the DNA-binding of the CLOCK:BMAL1 complex in mice. eLife 2013; 2:e00426. [PMID: 23580255 PMCID: PMC3622178 DOI: 10.7554/elife.00426] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Accepted: 02/12/2013] [Indexed: 11/13/2022] Open
Abstract
Genetic and molecular approaches have been critical for elucidating the mechanism of the mammalian circadian clock. Here, we demonstrate that the ClockΔ19 mutant behavioral phenotype is significantly modified by mouse strain genetic background. We map a suppressor of the ClockΔ19 mutation to a ∼900 kb interval on mouse chromosome 1 and identify the transcription factor, Usf1, as the responsible gene. A SNP in the promoter of Usf1 causes elevation of its transcript and protein in strains that suppress the Clock mutant phenotype. USF1 competes with the CLOCK:BMAL1 complex for binding to E-box sites in target genes. Saturation binding experiments demonstrate reduced affinity of the CLOCKΔ19:BMAL1 complex for E-box sites, thereby permitting increased USF1 occupancy on a genome-wide basis. We propose that USF1 is an important modulator of molecular and behavioral circadian rhythms in mammals. DOI:http://dx.doi.org/10.7554/eLife.00426.001.
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Affiliation(s)
- Kazuhiro Shimomura
- Center for Functional Genomics, Department of Neurobiology, Center for Sleep and Circadian Biology, Northwestern University, Evanston, United States
| | - Vivek Kumar
- Department of Neuroscience, Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, United States
| | - Nobuya Koike
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, United States
| | - Tae-Kyung Kim
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, United States
| | - Jason Chong
- Department of Neurobiology, Northwestern University, Evanston, United States
| | - Ethan D Buhr
- Department of Neurobiology, Northwestern University, Evanston, United States
| | - Andrew R Whiteley
- Department of Neurobiology, Northwestern University, Evanston, United States
| | - Sharon S Low
- Department of Neurobiology, Northwestern University, Evanston, United States
| | - Chiaki Omura
- Department of Neurobiology, Center for Functional Genomics, Northwestern University, Evanston, United States
| | - Deborah Fenner
- Department of Neurobiology, Center for Functional Genomics, Northwestern University, Evanston, United States
| | - Joseph R Owens
- Department of Neurobiology, Center for Sleep and Circadian Biology, Northwestern University, Evanston, United States
| | - Marc Richards
- Department of Neurobiology, Northwestern University, Evanston, United States
| | - Seung-Hee Yoo
- Department of Neuroscience, Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, United States
| | - Hee-Kyung Hong
- Department of Neurobiology, Center for Functional Genomics, Northwestern University, Evanston, United States
| | - Martha H Vitaterna
- Center for Functional Genomics, Department of Neurobiology, Center for Sleep and Circadian Biology, Northwestern University, Evanston, United States
| | - Joseph Bass
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, United States
| | - Mathew T Pletcher
- Department of Genomics, Genomics Institute of the Novartis Research Foundation, San Diego, United States
| | - Tim Wiltshire
- Department of Genomics, Genomics Institute of the Novartis Research Foundation, San Diego, United States
| | - John Hogenesch
- Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States
| | - Phillip L Lowrey
- Department of Neurobiology, Northwestern University, Evanston, United States
| | - Joseph S Takahashi
- Department of Neuroscience, Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, United States
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Kawasaki H, Doi R, Ito K, Shimoda M, Ishida N. The circadian binding of CLOCK protein to the promoter of C/ebpα gene in mouse cells. PLoS One 2013; 8:e58221. [PMID: 23505471 PMCID: PMC3594305 DOI: 10.1371/journal.pone.0058221] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Accepted: 02/01/2013] [Indexed: 11/30/2022] Open
Abstract
C/EBPα plays important roles in metabolism as well as in the maintenance of energy homeostasis. Here we describe loss of the circadian oscillation of C/ebpα expression in liver of Clock mutant mice. Reporter assays indicate Clock and Bmal significantly induced C/ebpα gene expression whereas Cry suppressed. Real time reporter assays showed that two mutated E-boxes disrupted C/ebpα promoter dependent-oscillation. Chromatin immunoprecipitation suggests Clock can bind to two E-boxes in the C/ebpα promoter with a circadian manner in vivo. Thus, C/ebpα gene transcription is under circadian control of a core clock component, Clock. The data suggests that circadian disturbances may affect metabolic abnormalities through the C/ebpα pathway in liver.
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Affiliation(s)
- Haruhisa Kawasaki
- Ishida Group of Clock Gene, Biomedical Research Institute, National Institute of Advanced Science and Technology (AIST) 6-5 Central, Tsukuba, Ibaraki, Japan
| | - Ryosuke Doi
- Ishida Group of Clock Gene, Biomedical Research Institute, National Institute of Advanced Science and Technology (AIST) 6-5 Central, Tsukuba, Ibaraki, Japan
- Graduate School of Life and Environmental Sciences, Tsukuba University, Tsukuba, Ibaraki, Japan
- Division of Cell Physiology, Department of Physiology and Cell Biology, Graduate School of Medicine, Kobe University, Kobe, Hyogo, Japan
| | - Kumpei Ito
- Ishida Group of Clock Gene, Biomedical Research Institute, National Institute of Advanced Science and Technology (AIST) 6-5 Central, Tsukuba, Ibaraki, Japan
- Graduate School of Life and Environmental Sciences, Tsukuba University, Tsukuba, Ibaraki, Japan
| | - Masami Shimoda
- Division of Insect Sciences, National Institute of Agrobiological Science, Tsukuba, Ibaraki, Japan
| | - Norio Ishida
- Ishida Group of Clock Gene, Biomedical Research Institute, National Institute of Advanced Science and Technology (AIST) 6-5 Central, Tsukuba, Ibaraki, Japan
- Graduate School of Life and Environmental Sciences, Tsukuba University, Tsukuba, Ibaraki, Japan
- * E-mail:
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31
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Chen Y, Li F, Ma Y, Chong K, Xu Y. Overexpression of OrbHLH001, a putative helix-loop-helix transcription factor, causes increased expression of AKT1 and maintains ionic balance under salt stress in rice. J Plant Physiol 2013; 170:93-100. [PMID: 23083684 DOI: 10.1016/j.jplph.2012.08.019] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2012] [Revised: 08/24/2012] [Accepted: 08/29/2012] [Indexed: 05/02/2023]
Abstract
The basic helix-loop-helix family of proteins, which function as transcription factors, have been intensively studied in plants and animals. However, the molecular mechanism of these factors contributing to stress tolerance is unknown. Here, we report on the overexpression of OrbHLH001 from Dongxiang wild rice (Oryza rufipogon) conferring salt tolerance in transgenic rice plants. The expression of OrbHLH001 was tissue specific, mainly in phloem tissues throughout the plant. Ion assay with the scanning ion-selective electrode technique showed that NaCl stress has a greater influence on Na(+) efflux and K(+) influx in OrbHLH001-overexpressed plants than the wild type. OrbHLH001 protein can induce the expression of OsAKT1 to regulate the Na(+)/K(+) ratio in OrbHLH001-overexpressed plants by specifically binding to an E-box motif in the promoter region of OsAKT1. The mechanism may have potential use in rice molecular breeding.
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Affiliation(s)
- Yuan Chen
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
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32
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Abstract
Low density lipoprotein receptor (LDLR) plays an important role in the cholesterol homeostasis. We examined the possible circadian regulation of LDLR and mechanism(s) underlying it. In mice, blood glucose and plasma triglyceride, total and high density lipoprotein cholesterol varied distinctively throughout a day. In addition, LDLR mRNA oscillated in the liver in a functional clock-dependent manner. Accordingly, analysis of human LDLR promoter sequence revealed three putative E-boxes, raising the possible regulation of LDLR expression by E-box-binding transcription factors. To test this possibility, human LDLR promoter reporter constructs were transfected into HepG2 cells and the effects of CLOCK/BMAL1, Hes1, and Hes6 expression were analyzed. It was found that positive circadian transcription factor complex CLOCK/BMAL1 upregulated human LDLR promoter activity in a serum-independent manner, while Hes family members Hes1 and Hes6 downregulated it only under serum-depleted conditions. Both effects were mapped to proximal promoter region of human LDLR, where mutation or deletion of well-known sterol regulatory element (SRE) abolished only the repressive effect of Hes1. Interestingly, hes6 and hes1 mRNA oscillated in an anti-phasic manner in the wild-type but not in the per1-/-per2 -/- mouse. Comparative analysis of mouse, rat and human hes6 genes revealed that three E-boxes are conserved among three species. Transfection and site-directed mutagenesis studies with hes6 reporter constructs confirmed that the third E-box in the exon IV is functionally induced by CLOCK/BMAL1. Taken together, these results suggest that LDLR expression is under circadian control involving CLOCK/BMAL1 and Hes family members Hes1 and Hes6.
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Affiliation(s)
- Yeon Ju Lee
- Department of Neuroscience and Neurodegeneration Control Research Center, Kyung Hee University, Seoul 130-701, Korea
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33
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Korenčič A, Bordyugov G, Košir R, Rozman D, Goličnik M, Herzel H. The interplay of cis-regulatory elements rules circadian rhythms in mouse liver. PLoS One 2012; 7:e46835. [PMID: 23144788 PMCID: PMC3489864 DOI: 10.1371/journal.pone.0046835] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Accepted: 09/05/2012] [Indexed: 01/08/2023] Open
Abstract
The mammalian circadian clock is driven by cell-autonomous transcriptional feedback loops that involve E-boxes, D-boxes, and ROR-elements. In peripheral organs, circadian rhythms are additionally affected by systemic factors. We show that intrinsic combinatorial gene regulation governs the liver clock. With a temporal resolution of 2 h, we measured the expression of 21 clock genes in mouse liver under constant darkness and equinoctial light-dark cycles. Based on these data and known transcription factor binding sites, we develop a six-variable gene regulatory network. The transcriptional feedback loops are represented by equations with time-delayed variables, which substantially simplifies modelling of intermediate protein dynamics. Our model accurately reproduces measured phases, amplitudes, and waveforms of clock genes. Analysis of the network reveals properties of the clock: overcritical delays generate oscillations; synergy of inhibition and activation enhances amplitudes; and combinatorial modulation of transcription controls the phases. The agreement of measurements and simulations suggests that the intrinsic gene regulatory network primarily determines the circadian clock in liver, whereas systemic cues such as light-dark cycles serve to fine-tune the rhythms.
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Affiliation(s)
- Anja Korenčič
- Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Grigory Bordyugov
- Institute for Theoretical Biology, Humboldt University, Berlin, Germany
| | - Rok Košir
- Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
- Center for Functional Genomics and Bio-Chips, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Damjana Rozman
- Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
- Center for Functional Genomics and Bio-Chips, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Marko Goličnik
- Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Hanspeter Herzel
- Institute for Theoretical Biology, Humboldt University, Berlin, Germany
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Swarnalatha M, Singh AK, Kumar V. The epigenetic control of E-box and Myc-dependent chromatin modifications regulate the licensing of lamin B2 origin during cell cycle. Nucleic Acids Res 2012; 40:9021-35. [PMID: 22772991 PMCID: PMC3467044 DOI: 10.1093/nar/gks617] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Revised: 05/11/2012] [Accepted: 05/31/2012] [Indexed: 12/27/2022] Open
Abstract
Recent genome-wide mapping of the mammalian replication origins has suggested the role of transcriptional regulatory elements in origin activation. However, the nature of chromatin modifications associated with such trans-factors or epigenetic marks imprinted on cis-elements during the spatio-temporal regulation of replication initiation remains enigmatic. To unveil the molecular underpinnings, we studied the human lamin B2 origin that spatially overlaps with TIMM 13 promoter. We observed an early G(1)-specific occupancy of c-Myc that facilitated the loading of mini chromosome maintenance protein (MCM) complex during subsequent mid-G(1) phase rather stimulating TIMM 13 gene expression. Investigations on the Myc-induced downstream events suggested a direct interaction between c-Myc and histone methyltransferase mixed-lineage leukemia 1 that imparted histone H3K4me3 mark essential for both recruitment of acetylase complex HBO1 and hyperacetylation of histone H4. Contemporaneously, the nucleosome remodeling promoted the loading of MCM proteins at the origin. These chromatin modifications were under the tight control of active demethylation of E-box as evident from methylation profiling. The active demethylation was mediated by the Ten-eleven translocation (TET)-thymine DNA glycosylase-base excision repair (BER) pathway, which facilitated spatio-temporal occupancy of Myc. Intriguingly, the genome-wide 43% occurrence of E-box among the human origins could support our hypothesis that epigenetic control of E-box could be a molecular switch for the licensing of early replicating origins.
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Affiliation(s)
| | | | - Vijay Kumar
- Virology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067, India
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Köberle M, Göppel D, Grandl T, Gaentzsch P, Manncke B, Berchtold S, Müller S, Lüscher B, Asselin-Labat ML, Pallardy M, Sorg I, Langer S, Barth H, Zumbihl R, Autenrieth IB, Bohn E. Yersinia enterocolitica YopT and Clostridium difficile toxin B induce expression of GILZ in epithelial cells. PLoS One 2012; 7:e40730. [PMID: 22792400 PMCID: PMC3392236 DOI: 10.1371/journal.pone.0040730] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Accepted: 06/14/2012] [Indexed: 12/14/2022] Open
Abstract
Glucocorticoid induced-leucine zipper (GILZ) has been shown to be induced in cells by different stimuli such as glucocorticoids, IL-10 or deprivation of IL-2. GILZ has anti-inflammatory properties and may be involved in signalling modulating apoptosis. Herein we demonstrate that wildtype Yersinia enterocolitica which carry the pYV plasmid upregulated GILZ mRNA levels and protein expression in epithelial cells. Infection of HeLa cells with different Yersinia mutant strains revealed that the protease activity of YopT, which cleaves the membrane-bound form of Rho GTPases was sufficient to induce GILZ expression. Similarly, Clostridium difficile toxin B, another bacterial inhibitor of Rho GTPases induced GILZ expression. YopT and toxin B both increased transcriptional activity of the GILZ promoter in HeLa cells. GILZ expression could not be linked to the inactivation of an individual Rho GTPase by these toxins. However, forced expression of RhoA and RhoB decreased basal GILZ promoter activity. Furthermore, MAPK activation proved necessary for profound GILZ induction by toxin B. Promoter studies and gel shift analyses defined binding of upstream stimulatory factor (USF) 1 and 2 to a canonical c-Myc binding site (E-box) in the GILZ promoter as a crucial step of its trans-activation. In addition we could show that USF-1 and USF-2 are essential for basal as well as toxin B induced GILZ expression. These findings define a novel way of GILZ promoter trans-activation mediated by bacterial toxins and differentiate it from those mediated by dexamethasone or deprivation of IL-2.
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Affiliation(s)
- Martin Köberle
- Interfaculty Institute of Microbiology and Infection Medicine, Eberhard Karls University of Tübingen, Tübingen, Germany
- Dermatology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - David Göppel
- Interfaculty Institute of Microbiology and Infection Medicine, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Tanja Grandl
- Interfaculty Institute of Microbiology and Infection Medicine, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Peer Gaentzsch
- Interfaculty Institute of Microbiology and Infection Medicine, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Birgit Manncke
- Interfaculty Institute of Microbiology and Infection Medicine, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Susanne Berchtold
- Interfaculty Institute of Microbiology and Infection Medicine, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Steffen Müller
- Interfaculty Institute of Microbiology and Infection Medicine, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Bernhard Lüscher
- Institut für Biochemie und Molekularbiologie, Universitätsklinikum RWTH Aachen, Aachen, Germany
| | - Marie-Liesse Asselin-Labat
- Universud, NSERM UMR-S 996, Faculte de Pharmacie Paris-Sud, Chatenay-Malabry, France
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, Australia
| | - Marc Pallardy
- Universud, NSERM UMR-S 996, Faculte de Pharmacie Paris-Sud, Chatenay-Malabry, France
| | - Isabel Sorg
- Biozentrum der Universität Basel, Basel, Switzerland
| | - Simon Langer
- Institute of Pharmacology and Toxicology, University of Ulm Medical Center, Ulm, Germany
| | - Holger Barth
- Institute of Pharmacology and Toxicology, University of Ulm Medical Center, Ulm, Germany
| | - Robert Zumbihl
- INRA, UMR1333, Laboratoire Diversité, Génomes et Interactions Microorganismes Insectes, Montpellier, France
- Université de Montpellier 2, Montpellier, France
| | - Ingo B. Autenrieth
- Interfaculty Institute of Microbiology and Infection Medicine, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Erwin Bohn
- Interfaculty Institute of Microbiology and Infection Medicine, Eberhard Karls University of Tübingen, Tübingen, Germany
- * E-mail:
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Zhao H, Zhu L, Jin Y, Ji H, Yan X, Zhu X. miR-375 is highly expressed and possibly transactivated by achaete-scute complex homolog 1 in small-cell lung cancer cells. Acta Biochim Biophys Sin (Shanghai) 2012; 44:177-82. [PMID: 22172490 DOI: 10.1093/abbs/gmr110] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
In this study, we identified five miRNAs highly expressed in the small-cell lung cancer (SCLC) cell line NCI-H209. Among them, the expression levels of miR-375 were dramatically elevated in all SCLC cell lines examined, coincident with the expression of the transcription factor achaete-scute complex homolog 1 (ASCL1). Moreover, miR-375 was upregulated and correlated with ASCL1 in the cell lines generated from mouse SCLC-like tumors as well. Dual-luciferase assays further showed that ASCL1 activated the expression of miR-375 by binding to the three E-box elements in the miR-375 promoter. These results imply a role of ASCL1 in SCLC via the upregulation of miR-375.
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Affiliation(s)
- Huijie Zhao
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, China
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Kanamoto N, Tagami T, Ueda-Sakane Y, Sone M, Miura M, Yasoda A, Tamura N, Arai H, Nakao K. Forkhead box A1 (FOXA1) and A2 (FOXA2) oppositely regulate human type 1 iodothyronine deiodinase gene in liver. Endocrinology 2012; 153:492-500. [PMID: 22067325 DOI: 10.1210/en.2011-1310] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Type 1 iodothyronine deiodinase (D1), a selenoenzyme that catalyzes the bioactivation of thyroid hormone, is expressed mainly in the liver. Its expression and activity are modulated by several factors, but the precise mechanism of its transcriptional regulation remains unclear. In the present study, we have analyzed the promoter of human D1 gene (hDIO1) to identify factors that prevalently increase D1 activity in the human liver. Deletion and mutation analyses demonstrated that a forkhead box (FOX)A binding site and an E-box site within the region between nucleotides -187 and -132 are important for hDIO1 promoter activity in the liver. EMSA demonstrated that FOXA1 and FOXA2 specifically bind to the FOXA binding site and that upstream stimulatory factor (USF) specifically binds to the E-box element. Overexpression of FOXA2 decreased hDIO1 promoter activity, and short interfering RNA-mediated knockdown of FOXA2 increased the expression of hDIO1 mRNA. In contrast, overexpression of USF1/2 increased hDIO1 promoter activity. Short interfering RNA-mediated knockdown of FOXA1 decreased the expression of hDIO1 mRNA, but knockdown of both FOXA1 and FOXA2 restored it. The response of the hDIO1 promoter to USF was greatly attenuated in the absence of FOXA1. Taken together, these results indicate that a balance of FOXA1 and FOXA2 expression modulates hDIO1 expression in the liver.
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Affiliation(s)
- Naotetsu Kanamoto
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan.
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Shima Y, Miyabayashi K, Baba T, Otake H, Katsura Y, Oka S, Zubair M, Morohashi KI. Identification of an enhancer in the Ad4BP/SF-1 gene specific for fetal Leydig cells. Endocrinology 2012; 153:417-25. [PMID: 22128023 DOI: 10.1210/en.2011-1407] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Adrenal 4 binding protein/steroidogenic factor 1 (Ad4BP/SF-1) (Nr5a1) is a nuclear receptor essential for reproductive tissue development and endocrine regulation. This factor is expressed in steroidogenic tissues (e.g. adrenal glands and gonads), and expression of this factor is tightly regulated in a tissue and cell type-specific manner. Our previous studies have identified tissue and cell type-specific enhancers in the introns of the Ad4BP/SF-1 gene in fetal adrenal glands, ventromedial hypothalamus, and pituitary gonadotrope. Characterization of the enhancers had provided new insights into tissue and cell development. However, these studies have failed to identify any gonad-specific enhancer. Here, we identified a fetal Leydig cell-specific enhancer in the upstream region of the mouse Ad4BP/SF-1 gene using transgenic mouse assays. Alignment of the upstream regions among vertebrate animal species demonstrated that the enhancer consisted of three conserved regions, whereby the most highly conserved region contained an Ad4BP/SF-1 binding sequence and an E-box. Mutation of each sequence abolished the enhancer activity and led to a loss of reporter gene expression. These results suggested that Ad4BP/SF-1 gene expression in the fetal Leydig cell is regulated by a yet unidentified E-box binding protein(s) and by an autoregulatory loop formed by Ad4BP/SF-1. Although fetal Leydig cells have been thought to play crucial roles for masculinization of various fetal tissues through androgen production, other functions have remained elusive. Our identification of a fetal Leydig cell-specific enhancer in the Ad4BP/SF-1 gene would be a powerful tool to address these gaps in the knowledge base.
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Affiliation(s)
- Yuichi Shima
- Department of Molecular Biology, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Fukuoka 812-8582, Japan
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39
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Groszmann M, Paicu T, Alvarez JP, Swain SM, Smyth DR. SPATULA and ALCATRAZ, are partially redundant, functionally diverging bHLH genes required for Arabidopsis gynoecium and fruit development. Plant J 2011; 68:816-29. [PMID: 21801252 DOI: 10.1111/j.1365-313x.2011.04732.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The Arabidopsis gynoecium is a complex organ that facilitates fertilization, later developing into a dehiscent silique that protects seeds until their dispersal. Identifying genes important for development is often hampered by functional redundancy. We report unequal redundancy between two closely related genes, SPATULA (SPT) and ALCATRAZ (ALC), revealing previously unknown developmental roles for each. SPT is known to support septum, style and stigma development in the flower, whereas ALC is involved in dehiscence zone development in the fruit. ALC diverged from a SPT-like ancestor following gene duplication coinciding with the At-β polyploidy event. Here we show that ALC is also involved in early gynoecium development, and SPT in later valve margin generation in the silique. Evidence includes the increased severity of early gynoecium disruption, and of later valve margin defects, in spt-alc double mutants. In addition, a repressive version of SPT (35S:SPT-SRDX) disrupts both structures. Consistent with redundancy, ALC and SPT expression patterns overlap in these tissues, and the ALC promoter carries two atypical E-box elements identical to one in SPT required for valve margin expression. Further, SPT can heterodimerize with ALC, and 35S:SPT can fully complement dehiscence defects in alc mutants, although 35S:ALC can only partly complement spt gynoecium disruptions, perhaps associated with its sequence simplification. Interactions with FRUITFULL and SHATTERPROOF genes differ somewhat between SPT and ALC, reflecting their different specializations. These two genes are apparently undergoing subfunctionalization, with SPT essential for earlier carpel margin tissues, and ALC specializing in later dehiscence zone development.
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MESH Headings
- Amino Acid Sequence
- Arabidopsis/genetics
- Arabidopsis/growth & development
- Arabidopsis/metabolism
- Arabidopsis Proteins/genetics
- Arabidopsis Proteins/metabolism
- Basic Helix-Loop-Helix Transcription Factors/genetics
- Basic Helix-Loop-Helix Transcription Factors/metabolism
- Chromosomes, Plant
- Conserved Sequence
- E-Box Elements
- Flowers/genetics
- Flowers/growth & development
- Flowers/ultrastructure
- Fruit/genetics
- Fruit/growth & development
- Gene Duplication
- Gene Expression Regulation, Plant
- Genes, Plant
- Genes, Reporter
- Genetic Complementation Test
- Microscopy, Electron, Scanning
- Molecular Sequence Data
- Plants, Genetically Modified/genetics
- Plants, Genetically Modified/growth & development
- Plants, Genetically Modified/metabolism
- Promoter Regions, Genetic
- Sequence Alignment
- Two-Hybrid System Techniques
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Affiliation(s)
- Michael Groszmann
- School of Biological Sciences, Monash University, Melbourne, Vic. 3800, Australia
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40
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Wankhade UD, Good DJ. Melanocortin 4 receptor is a transcriptional target of nescient helix-loop-helix-2. Mol Cell Endocrinol 2011; 341:39-47. [PMID: 21664420 PMCID: PMC3143283 DOI: 10.1016/j.mce.2011.05.022] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Revised: 04/27/2011] [Accepted: 05/09/2011] [Indexed: 11/19/2022]
Abstract
Melanocortin 4 receptor (Mc4r/MC4R) is a G-Protein coupled receptor that is expressed in the hypothalamus and implicated in body weight control. Mutations in MC4R are the most frequent cause of monogenetic forms of human obesity. Despite its importance, the MC4R signaling pathways and transcriptional regulation underlying the melanocortin pathway are far from being fully understood. The transcription factor nescient helix-loop-helix 2 (Nhlh2) influences the melanocortin pathway through transcriptional regulation of prohormone convertase I, which influences the production of melanocortin peptides. In the present study, Nhlh2's role as a transcriptional regulator of Mc4r has been demonstrated. Nhlh2 knockout mice have reduced hypothalamic expression of Mc4r mRNA, suggesting that it could be a direct or indirect transcriptional regulator of the Mc4r promoter. To demonstrate direct transcriptional regulation, chromatin immunoprecipitation and electrophoretic gel shift assays show that Nhlh2 binds to the E-Boxes located at -551, -366 and +54 on the Mc4r promoter. Leptin-induced transactivation of the Mc4r promoter is significantly higher in the presence of exogenously added Nhlh2. siRNA knockdown of Nhlh2 leads to significantly reduced endogenous Mc4r mRNA expression levels in N29/2 cell line. Transactivation using promoters with mutations in each of the E-Boxes results in significantly reduced transactivation efficiency compared to the WT Mc4r promoter, suggesting that Nhlh2 regulates Mc4r transcription through these sites. Findings from these studies, combined with previous work implicating Nhlh2 as a transcriptional regulator of both the Mc4r gene and the melanocortin pathway, suggest that Nhlh2's transcriptional activity directly influences the human and rodent body weight control pathways.
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Affiliation(s)
- Umesh D. Wankhade
- Department of Human Nutrition, Foods and Exercise, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061
| | - Deborah J. Good
- Department of Human Nutrition, Foods and Exercise, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061
- Corresponding Author: Dr. Deborah J. Good, Department of Human Nutrition Foods and Exercise, Corporate Research Center, Research Building 23 (0913), Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, Tel: 540-231-0430; Fax: 540-231-5522,
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41
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Kuzin A, Kundu M, Brody T, Odenwald WF. Functional analysis of conserved sequences within a temporally restricted neural precursor cell enhancer. Mech Dev 2011; 128:165-77. [PMID: 21315151 DOI: 10.1016/j.mod.2011.02.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2010] [Revised: 01/28/2011] [Accepted: 02/02/2011] [Indexed: 11/18/2022]
Abstract
Many of the key regulators of Drosophila CNS neural identity are expressed in defined temporal orders during neuroblast (NB) lineage development. To begin to understand the structural and functional complexity of enhancers that regulate ordered NB gene expression programs, we have undertaken the mutational analysis of the temporally restricted nerfin-1 NB enhancer. Our previous studies have localized the enhancer to a region just proximal to the nerfin-1 transcription start site. Analysis of this enhancer, using the phylogenetic footprint program EvoPrinter, reveals the presence of multiple sequence blocks that are conserved among drosophilids. cis-Decoder alignments of these conserved sequence blocks (CSBs) has identified shorter elements that are conserved in other Drosophila NB enhancers. Mutagenesis of the enhancer reveals that although each CSB is required for wild-type expression, neither position nor orientation of the CSBs within the enhancer is crucial for enhancer function; removal of less-conserved or non-conserved sequences flanking CSB clusters also does not significantly alter enhancer activity. While all three conserved E-box transcription factor (TF) binding sites (CAGCTG) are required for full function, adding an additional site at different locations within non-conserved sequences interferes with enhancer activity. Of particular note, none of the mutations resulted in ectopic reporter expression outside of the early NB expression window, suggesting that the temporally restricted pattern is defined by transcriptional activators and not by direct DNA binding repressors. Our work also points to an unexpectedly large number of TFs required for optimal enhancer function - mutant TF analysis has identified at least four that are required for full enhancer regulation.
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Affiliation(s)
- Alexander Kuzin
- Neural Cell-Fate Determinants Section, NINDS, NIH Bethesda, MD, USA.
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42
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Hu CH, Hong B, Xu WH. Identification of an E-box DNA binding protein, activated protein 4, and its function in regulating the expression of the gene encoding diapause hormone and pheromone biosynthesis-activating neuropeptide in Helicoverpa armigera. Insect Mol Biol 2010; 19:243-252. [PMID: 20088871 DOI: 10.1111/j.1365-2583.2009.00983.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Activated protein 4 (AP-4), an E-box DNA-binding protein, was cloned from the cotton bollworm, Helicoverpa armigera (Har). The expression of Har-AP-4 mRNA and the protein that it encodes are significantly higher in nondiapause pupae than in diapause pupae. In vitro-translated Har-AP-4 can bind specifically to the E-box motif on the promoter of the diapause hormone and pheromone biosynthesis-activating neuropeptide (DH-PBAN). Har-AP-4, fused with the green fluorescent protein (GFP), is localized to the nucleus, and overexpression of Har-AP-4 can significantly activate the promoter of the DH-PBAN gene that is involved in nondiapause pupal development in H. armigera. These results suggest that Har-AP-4, which binds to the promoter of DH-PBAN, may play a role in regulating pupal development in H. armigera.
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Affiliation(s)
- C-H Hu
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen (Zhongshan) University, Guangzhou, China
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43
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Balakumaran BS, Porrello A, Hsu DS, Glover W, Foye A, Leung JY, Sullivan BA, Hahn WC, Loda M, Febbo PG. MYC activity mitigates response to rapamycin in prostate cancer through eukaryotic initiation factor 4E-binding protein 1-mediated inhibition of autophagy. Cancer Res 2009; 69:7803-10. [PMID: 19773438 PMCID: PMC2756305 DOI: 10.1158/0008-5472.can-09-0910] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Loss of PTEN and activation of phosphoinositide 3-kinase are commonly observed in advanced prostate cancer. Inhibition of mammalian target of rapamycin (mTOR), a downstream target of phosphoinositide 3-kinase signaling, results in cell cycle arrest and apoptosis in multiple in vitro and in vivo models of prostate cancer. However, single-agent use of mTOR inhibition has limited clinical success, and the identification of molecular events mitigating tumor response to mTOR inhibition remains a critical question. Here, using genetically engineered human prostate epithelial cells (PrEC), we show that MYC, a frequent target of genetic gain in prostate cancers, abrogates sensitivity to rapamycin by decreasing rapamycin-induced cytostasis and autophagy. Analysis of MYC and the mTOR pathway in human prostate tumors and PrEC showed selective increased expression of eukaryotic initiation factor 4E-binding protein 1 (4EBP1) with gain in MYC copy number or forced MYC expression, respectively. We have also found that MYC binds to regulatory regions of the 4EBP1 gene. Suppression of 4EBP1 expression resulted in resensitization of MYC-expressing PrEC to rapamycin and increased autophagy. Taken together, our findings suggest that MYC expression abrogates sensitivity to rapamycin through increased expression of 4EBP1 and reduced autophagy.
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Affiliation(s)
| | | | - David S. Hsu
- Duke Institute for Genome Sciences & Policy, Duke University, Durham, NC
- Division of Medical Oncology, Department of Medicine, Duke University Medical Center, Durham, NC
| | - Wayne Glover
- Duke Institute for Genome Sciences & Policy, Duke University, Durham, NC
| | - Adam Foye
- Duke Institute for Genome Sciences & Policy, Duke University, Durham, NC
| | - Janet Y. Leung
- Duke Institute for Genome Sciences & Policy, Duke University, Durham, NC
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham NC
| | - Beth A. Sullivan
- Duke Institute for Genome Sciences & Policy, Duke University, Durham, NC
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham NC
| | - William C. Hahn
- Department of Medical Oncology, Dana Farber Cancer Institute, Boston MA
- Broad Institute of Harvard and MIT, Cambridge, MA
| | - Massimo Loda
- Department of Pathology, Dana Farber Cancer Institute, Boston MA
| | - Phillip G. Febbo
- Duke Institute for Genome Sciences & Policy, Duke University, Durham, NC
- Division of Medical Oncology, Department of Medicine, Duke University Medical Center, Durham, NC
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham NC
- Duke Comprehensive Cancer Center, Duke University, Durham, NC
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44
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Matsuoka Y, Uehara N, Tsubura A. hnRNP U interacts with the c-Myc-Max complex on the E-box promoter region inducing the ornithine decarboxylase gene. Oncol Rep 2009; 22:249-255. [PMID: 19578763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023] Open
Abstract
The promoter of the ornithine decarboxylase (ODC) gene contains two E-boxes, which are critical sites for transcriptional activation by the binding of c-Myc-Max heterodimers. We have identified heterogeneous nuclear ribonuclear protein U (hnRNP U) as a component of the complex formed on the E-box-containing promoter region of the ODC gene by using DNA-affinity chromatography, immunoprecipitation and chromatin immunoprecipitation assays. The N-terminal domain of hnRNP U was responsible for the association with c-Myc-Max complex. Down-regulation of hnRNP U with RNA interference blocked the induction of the ODC gene and cell growth by serum stimulation, suggesting that hnRNP U is a coactivator of the c-Myc-Max complex and essential for cell proliferation. Electrophoretic mobility-shift assays revealed that the segment between the two E-boxes in the promoter is the primary binding site of hnRNP U. The putative binding sequence was narrowed-down to a 13-nucleotide segment by comparing the sequence between the E-boxes with the binding sites of hnRNP U, which were recently identified in the promoter of Bmal1, a core component of the circadian molecular oscillator. These findings increase our knowledge of how the c-Myc-Max complex exerts its transcriptional regulatory role and suggest that hnRNP U may be a coactivator of this transcriptional activator complex.
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Affiliation(s)
- Yoichiro Matsuoka
- Second Department of Pathology, Kansai Medical University, Osaka 570-8506, Japan.
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45
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Yoshitane H, Takao T, Satomi Y, Du NH, Okano T, Fukada Y. Roles of CLOCK phosphorylation in suppression of E-box-dependent transcription. Mol Cell Biol 2009; 29:3675-86. [PMID: 19414601 PMCID: PMC2698759 DOI: 10.1128/mcb.01864-08] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2008] [Revised: 01/21/2009] [Accepted: 04/15/2009] [Indexed: 12/29/2022] Open
Abstract
In mammalian circadian clockwork, the CLOCK-BMAL1 heterodimer activates E-box-dependent transcription, while its activity is suppressed by circadian binding with negative regulators, such as CRYs. Here, we found that the CLOCK protein is kept mostly in the phosphorylated form throughout the day and is partly hyperphosphorylated in the suppression phase of E-box-dependent transcription in the mouse liver and NIH 3T3 cells. Coexpression of CRY2 in NIH 3T3 cells inhibited the phosphorylation of CLOCK, whereas CIPC coexpression markedly stimulated phosphorylation, indicating that CLOCK phosphorylation is regulated by a combination of the negative regulators in the suppression phase. CLOCK-BMAL1 purified from the mouse liver was subjected to tandem mass spectrometry analysis, which identified Ser38, Ser42, and Ser427 as in vivo phosphorylation sites of CLOCK. Ser38Asp and Ser42Asp mutations of CLOCK additively and markedly weakened the transactivation activity of CLOCK-BMAL1, with downregulation of the nuclear amount of CLOCK and the DNA-binding activity. On the other hand, CLOCK Delta 19, lacking the CIPC-binding domain, was far less phosphorylated and much more stabilized than wild-type CLOCK in vivo. Calyculin A treatment of cultured NIH 3T3 cells promoted CLOCK phosphorylation and facilitated its proteasomal degradation. Together, these results show that CLOCK phosphorylation contributes to the suppression of CLOCK-BMAL1-mediated transactivation through dual regulation: inhibition of CLOCK activity and promotion of its degradation.
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Affiliation(s)
- Hikari Yoshitane
- Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan
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Abstract
Max-E47 is a designed hybrid protein comprising the Max DNA-binding basic region and E47 HLH dimerization subdomain. In the yeast one-hybrid system (Y1H), Max-E47 shows strong transcriptional activation from the E-box site, 5'-CACGTG, targeted by the Myc/Max/Mad network of transcription factors; two mutants, Max-E47Y and Max-E47YF, activate more weakly from the E-box in the Y1H. Quantitative fluorescence anisotropy titrations to gain free energies of protein:DNA binding gave low nanomolar K(d) values for the native MaxbHLHZ, Max-E47, and the Y and YF mutants binding to the E-box site (14, 15, 9, and 6 nM, respectively), with no detectable binding to a nonspecific control duplex. Because these minimalist, E-box-binding hybrids have no activation domain and no interactions with the c-MycbHLHZ, as shown by the yeast two-hybrid assay, they can potentially serve as dominant-negative inhibitors that suppress activation of E-box-responsive genes targeted by transcription factors including the c-Myc/Max complex. As proof-of-principle, we used our modified Y1H, which allows direct competition between two proteins vying for a DNA target, to show that Max-E47 effectively outcompetes the native MaxbHLHZ for the E-box; weaker competition is observed from the two mutants, consistent with Y1H results. These hybrids provide a minimalist scaffold for further exploration of the relationship between protein structure and DNA-binding function and may have applications as protein therapeutics or biochemical probes capable of targeting the E-box site.
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Affiliation(s)
- Jing Xu
- Department of Chemistry, University of Toronto, Mississauga, Ontario L5L 1C6, Canada
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47
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Han W, Wu Z, Zhao Y, Meng Y, Si Y, Yang J, Fu X, Yu L. FHL2 interacts with and acts as a functional repressor of Id2 in human neuroblastoma cells. Nucleic Acids Res 2009; 37:3996-4009. [PMID: 19417068 PMCID: PMC2709579 DOI: 10.1093/nar/gkp332] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Inhibitor of differentiation 2 (Id2) is a natural inhibitor of the basic helix–loop–helix transcription factors. Although Id2 is well known to prevent differentiation and promote cell-cycle progression and tumorigenesis, the molecular events that regulate Id2 activity remain to be investigated. Here, we identified that Four-and-a-half LIM-only protein 2 (FHL2) is a novel functional repressor of Id2. Moreover, we demonstrated that FHL2 can directly interact with all members of the Id family (Id1–4) via an N-terminal loop–helix structure conserved in Id proteins. FHL2 antagonizes the inhibitory effect of Id proteins on basic helix–loop–helix protein E47-mediated transcription, which was abrogated by the deletion mutation of Ids that disrupted their interaction with FHL2. We also showed a competitive nature between FHL2 and E47 for binding Id2, whereby FHL2 prevents the formation of the Id2–E47 heterodimer, thus releasing E47 to DNA and restoring its transcriptional activity. FHL2 expression was remarkably up-regulated during retinoic acid-induced differentiation of neuroblastoma cells, during which the expression of Id2 was opposite to that. Ectopic FHL2 expression in neuroblastoma cells markedly reduces the transcriptional and cell-cycle promoting functions of Id2. Altogether, these results indicate that FHL2 is an important repressor of the oncogenic activity of Id2 in neuroblastoma cells.
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Affiliation(s)
- Weidong Han
- Department of Molecular Biology, Chinese PLA General Hospital, Beijing 100853, China.
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48
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Sun Y, Ishibashi M, Seimon T, Lee M, Sharma SM, Fitzgerald KA, Samokhin AO, Wang Y, Sayers S, Aikawa M, Jerome WG, Ostrowski MC, Bromme D, Libby P, Tabas IA, Welch CL, Tall AR. Free cholesterol accumulation in macrophage membranes activates Toll-like receptors and p38 mitogen-activated protein kinase and induces cathepsin K. Circ Res 2009; 104:455-65. [PMID: 19122179 DOI: 10.1161/circresaha.108.182568] [Citation(s) in RCA: 126] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The molecular events linking lipid accumulation in atherosclerotic plaques to complications such as aneurysm formation and plaque disruption are poorly understood. BALB/c-Apoe(-/-) mice bearing a null mutation in the Npc1 gene display prominent medial erosion and atherothrombosis, whereas their macrophages accumulate free cholesterol in late endosomes and show increased cathepsin K (Ctsk) expression. We now show increased cathepsin K immunostaining and increased cysteinyl proteinase activity using near infrared fluorescence imaging over proximal aortas of Apoe(-/-), Npc1(-/-) mice. In mechanistic studies, cholesterol loading of macrophage plasma membranes (cyclodextrin-cholesterol) or endosomal system (AcLDL+U18666A or Npc1 null mutation) activated Toll-like receptor (TLR) signaling, leading to sustained phosphorylation of p38 mitogen-activated protein kinase and induction of p38 targets, including Ctsk, S100a8, Mmp8, and Mmp14. Studies in macrophages from knockout mice showed major roles for TLR4, following plasma membrane cholesterol loading, and for TLR3, after late endosomal loading. TLR signaling via p38 led to phosphorylation and activation of the transcription factor Microphthalmia transcription factor, acting at E-box elements in the Ctsk promoter. These studies suggest that free cholesterol enrichment of either plasma or endosomal membranes in macrophages leads to activation of signaling via various TLRs, prolonged p38 mitogen-activated protein kinase activation, and induction of Mmps, Ctsk, and S100a8, potentially contributing to plaque complications.
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Affiliation(s)
- Yu Sun
- Department of Medicine, Columbia University, New York, NY 10032, USA.
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Samarakoon R, Higgins PJ. Integration of non-SMAD and SMAD signaling in TGF-beta1-induced plasminogen activator inhibitor type-1 gene expression in vascular smooth muscle cells. Thromb Haemost 2008; 100:976-83. [PMID: 19132220 PMCID: PMC2963177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Overexpression of plasminogen activator inhibitor-1 (SERPINE1, PAI-1), the major physiological inhibitor of pericellular plasmin generation, is a significant causative factor in the progression of vascular disorders (e.g. arteriosclerosis, thrombosis, perivascular fibrosis) as well as a biomarker and a predictor of cardiovascular-disease associated mortality. PAI-1 is a temporal/spatial regulator of pericellular proteolysis and ECM accumulation impacting, thereby, vascular remodeling, smooth muscle cell migration, proliferation and apoptosis. Within the specific context of TGF-beta1-initiated vascular fibrosis and neointima formation, PAI-1 is a member of the most prominently expressed subset of TGF-beta1-induced transcripts. Recent findings implicate EGFR/pp60c-src-->MEK/ERK1/2 and Rho/ROCK-->SMAD2/3 signaling in TGF-beta1-stimulated PAI-1 expression in vascular smooth muscle cells. The EGFR is a direct upstream regulator of MEK/ERK1/2 while Rho/ROCK modulate both the duration of SMAD2/3 phosphorylation and nuclear accumulation. E-box motifs (CACGTG) in the PE1/PE2 promoter regions of the human PAI-1 gene, moreover, are platforms for a MAP kinase-directed USF subtype switch (USF-1-->USF-2) in response to growth factor addition suggesting that the EGFR-->MEK/ERK axis impacts PAI-1 expression, at least partly, through USF-dependent transcriptional controls. This paper reviews recent data suggesting the essential cooperativity among the EGFR-->MAP kinase cascade, the Rho/ROCK pathway and SMADs in TGF-beta1-initiated PAI-1 expression. The continued clarification of mechanistic controls on PAI-1 transcription may lead to new targeted therapies and clinically-relevant options for the treatment of vascular diseases in which PAI-1 dysregulation is a major underlying pathogenic feature.
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Affiliation(s)
- Rohan Samarakoon
- Center for Cell Biology & Cancer Research, Albany Medical College, 47 New Scotland Avenue, Albany, New York 12208, USA
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50
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Teye K, Okamoto K, Tanaka Y, Umata T, Ohnuma M, Moroi M, Kimura H, Tsuneoka M. Expression of the TAF4b gene is induced by MYC through a non-canonical, but not canonical, E-box which contributes to its specific response to MYC. Int J Oncol 2008; 33:1271-1280. [PMID: 19020761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023] Open
Abstract
Transcription factor binding sites are short DNA sequences that interact with transcription factors and the proper control of gene expression appears to require the mechanisms including the regulation through the genome context around the transcription factor binding sites. The MYC proteins are central regulators of cell growth. Many genes have been reported to be regulated by MYC through E-box sites. However, the characters of E-box that Myc selects to function are not clear and identification of additional genes controlled by MYC will provide information to completely understand the functions of MYC. Here we report that MYC directly induces TAF4b expression. We mapped the transcription start site and characterized functional promoter elements for MYC response in the TAF4b promoter. There are several E-box sequences near the transcription start site, including canonical (CACGTG) and non-canonical (CGCGTG) ones. We found that c-MYC induces TAF4b expression through one of the non-canonical E-box sites, which is in a highly conserved region of TAF4b promoters in mammals, suggesting the importance of the genome context around the target E-box. When the non-canonical E-box in the TAF4b promoter was mutated to a canonical one, MYC functioned on both E-boxes, while another E-box-binding transcription factor, USF, did so on only the canonical E-box. These results suggest that in addition to the context where the target E-box exists, a sequence within an E-box is involved in the mechanisms by which specific E-box sites are selected by Myc.
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Affiliation(s)
- Kwesi Teye
- Faculty of Pharmacy, Takasaki University of Health and Welfare, Takasaki 370-0033 Japan
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