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Lederbauer J, Das S, Piton A, Lessel D, Kreienkamp HJ. The role of DEAD- and DExH-box RNA helicases in neurodevelopmental disorders. Front Mol Neurosci 2024; 17:1414949. [PMID: 39149612 PMCID: PMC11324592 DOI: 10.3389/fnmol.2024.1414949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2024] [Accepted: 07/22/2024] [Indexed: 08/17/2024] Open
Abstract
Neurodevelopmental disorders (NDDs) represent a large group of disorders with an onset in the neonatal or early childhood period; NDDs include intellectual disability (ID), autism spectrum disorders (ASD), attention deficit hyperactivity disorders (ADHD), seizures, various motor disabilities and abnormal muscle tone. Among the many underlying Mendelian genetic causes for these conditions, genes coding for proteins involved in all aspects of the gene expression pathway, ranging from transcription, splicing, translation to the eventual RNA decay, feature rather prominently. Here we focus on two large families of RNA helicases (DEAD- and DExH-box helicases). Genetic variants in the coding genes for several helicases have recently been shown to be associated with NDD. We address genetic constraints for helicases, types of pathological variants which have been discovered and discuss the biological pathways in which the affected helicase proteins are involved.
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Affiliation(s)
- Johannes Lederbauer
- Institute of Human Genetics, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Sarada Das
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Amelie Piton
- Department of Translational Medicine and Neurogenetics, Institute of Genetics and Molecular and Cellular Biology, Strasbourg University, CNRS UMR7104, INSERM U1258, Illkirch, France
| | - Davor Lessel
- Institute of Human Genetics, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Hans-Jürgen Kreienkamp
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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2
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Zheng B, Chen X, Ling Q, Cheng Q, Ye S. Role and therapeutic potential of DEAD-box RNA helicase family in colorectal cancer. Front Oncol 2023; 13:1278282. [PMID: 38023215 PMCID: PMC10654640 DOI: 10.3389/fonc.2023.1278282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 10/12/2023] [Indexed: 12/01/2023] Open
Abstract
Colorectal cancer (CRC) is the third most commonly diagnosed and the second cancer-related death worldwide, leading to more than 0.9 million deaths every year. Unfortunately, this disease is changing rapidly to a younger age, and in a more advanced stage when diagnosed. The DEAD-box RNA helicase proteins are the largest family of RNA helicases so far. They regulate almost every aspect of RNA physiological processes, including RNA transcription, editing, splicing and transport. Aberrant expression and critical roles of the DEAD-box RNA helicase proteins have been found in CRC. In this review, we first summarize the protein structure, cellular distribution, and diverse biological functions of DEAD-box RNA helicases. Then, we discuss the distinct roles of DEAD-box RNA helicase family in CRC and describe the cellular mechanism of actions based on recent studies, with an aim to provide future strategies for the treatment of CRC.
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Affiliation(s)
- Bichun Zheng
- Department of Anorectal Surgery, The Affiliated People’s Hospital of Ningbo University, Ningbo, China
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3
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Bohnsack KE, Yi S, Venus S, Jankowsky E, Bohnsack MT. Cellular functions of eukaryotic RNA helicases and their links to human diseases. Nat Rev Mol Cell Biol 2023; 24:749-769. [PMID: 37474727 DOI: 10.1038/s41580-023-00628-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/13/2023] [Indexed: 07/22/2023]
Abstract
RNA helicases are highly conserved proteins that use nucleoside triphosphates to bind or remodel RNA, RNA-protein complexes or both. RNA helicases are classified into the DEAD-box, DEAH/RHA, Ski2-like, Upf1-like and RIG-I families, and are the largest class of enzymes active in eukaryotic RNA metabolism - virtually all aspects of gene expression and its regulation involve RNA helicases. Mutation and dysregulation of these enzymes have been linked to a multitude of diseases, including cancer and neurological disorders. In this Review, we discuss the regulation and functional mechanisms of RNA helicases and their roles in eukaryotic RNA metabolism, including in transcription regulation, pre-mRNA splicing, ribosome assembly, translation and RNA decay. We highlight intriguing models that link helicase structure, mechanisms of function (such as local strand unwinding, translocation, winching, RNA clamping and displacing RNA-binding proteins) and biological roles, including emerging connections between RNA helicases and cellular condensates formed through liquid-liquid phase separation. We also discuss associations of RNA helicases with human diseases and recent efforts towards the design of small-molecule inhibitors of these pivotal regulators of eukaryotic gene expression.
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Affiliation(s)
- Katherine E Bohnsack
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany.
| | - Soon Yi
- Center for RNA Science and Therapeutics, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
- Department of Biochemistry, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Sarah Venus
- Center for RNA Science and Therapeutics, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
- Department of Biochemistry, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Eckhard Jankowsky
- Center for RNA Science and Therapeutics, School of Medicine, Case Western Reserve University, Cleveland, OH, USA.
- Department of Biochemistry, School of Medicine, Case Western Reserve University, Cleveland, OH, USA.
- Case Comprehensive Cancer Center, School of Medicine, Case Western Reserve University, Cleveland, OH, USA.
- Moderna, Cambridge, MA, USA.
| | - Markus T Bohnsack
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany.
- Göttingen Centre for Molecular Biosciences, University of Göttingen, Göttingen, Germany.
- Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.
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4
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Saavedra-Peña RDM, Taylor N, Flannery C, Rodeheffer MS. Estradiol cycling drives female obesogenic adipocyte hyperplasia. Cell Rep 2023; 42:112390. [PMID: 37053070 PMCID: PMC10567995 DOI: 10.1016/j.celrep.2023.112390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 12/21/2022] [Accepted: 03/29/2023] [Indexed: 04/14/2023] Open
Abstract
White adipose tissue (WAT) distribution is sex dependent. Adipocyte hyperplasia contributes to WAT distribution in mice driven by cues in the tissue microenvironment, with females displaying hyperplasia in subcutaneous and visceral WAT, while males and ovariectomized females have visceral WAT (VWAT)-specific hyperplasia. However, the mechanism underlying sex-specific hyperplasia remains elusive. Here, transcriptome analysis in female mice shows that high-fat diet (HFD) induces estrogen signaling in adipocyte precursor cells (APCs). Analysis of APCs throughout the estrous cycle demonstrates increased proliferation only when proestrus (high estrogen) coincides with the onset of HFD feeding. We further show that estrogen receptor α (ERα) is required for this proliferation and that estradiol treatment at the onset of HFD feeding is sufficient to drive it. This estrous influence on APC proliferation leads to increased obesity driven by adipocyte hyperplasia. These data indicate that estrogen drives ERα-dependent obesogenic adipocyte hyperplasia in females, exacerbating obesity and contributing to the differential fat distribution between the sexes.
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Affiliation(s)
- Rocío Del M Saavedra-Peña
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520, USA
| | - Natalia Taylor
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520, USA
| | - Clare Flannery
- Department of Obstetrics, Gynecology and Reproductive Sciences, Yale University, New Haven, CT 06520, USA; Section of Endocrinology and Metabolism, Yale University, New Haven, CT 06520, USA
| | - Matthew S Rodeheffer
- Department of Comparative Medicine, Yale University, New Haven, CT 06520, USA; Department of Cellular and Molecular Physiology, Yale University, New Haven, CT 06520, USA; Yale Center for Molecular and Systems Metabolism, Yale University, New Haven, CT 06520, USA; Yale Stem Cell Center, Yale University School of Medicine, New Haven, CT 06520, USA.
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5
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Yu Y, Wang JL, Meng LL, Hu CT, Yan ZW, He ZP, Shi XQ, Fu GH, Zu LD. DDX54 Plays a Cancerous Role Through Activating P65 and AKT Signaling Pathway in Colorectal Cancer. Front Oncol 2021; 11:650360. [PMID: 33968751 PMCID: PMC8097168 DOI: 10.3389/fonc.2021.650360] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 03/17/2021] [Indexed: 12/15/2022] Open
Abstract
Colorectal cancer (CRC) is one of the most malignant cancers, and its incidence is still steadily increasing. The DDX RNA helicase family members have been found to play a role in various cancers; however, the role of DDX54 in colorectal cancer is still unclear and needed to be defined. Here, we found DDX54 was overexpressed in CRC tissues by the label-free mass spectrum, which was also verified in tissue microarray of colon cancer, as well as the CRC cell lines and TCGA database. High DDX54 level was correlated with tumor stage and distant metastasis, which always indicated a poor prognosis to the CRC patients. DDX54 could promote the proliferation and mobility of CRC cells through increasing the phosphorylation level p65 and AKT leading to the tumorigenesis. Here, we have preliminarily studied the function of DDX54 in CRC, which would improve our understanding of the underlying biology of CRC and provide the new insight that could be translated into novel therapeutic approaches.
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Affiliation(s)
- Yi Yu
- Pathology Center, Shanghai General Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Jing-Long Wang
- Department of Pathology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Li-Li Meng
- Department of Pathology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Chun-Ting Hu
- Department of Pathology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zhao-Wen Yan
- Department of Pathology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zhi-Ping He
- Department of Pathology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiao-Qin Shi
- Pathology Center, Shanghai General Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Guo-Hui Fu
- Pathology Center, Shanghai General Hospital, Shanghai Jiao Tong University, Shanghai, China
- Department of Pathology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Li-Dong Zu
- Department of Pathology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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6
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Xu Y, Wang Y, Yuan C, Sheng X, Sha R, Dai H, Zhang S, Wang Y, Lin Y, Zhou L, Xu S, Zhang J, Yin W, Lu J. Predictive and prognostic value of EPIC1 in patients with breast cancer receiving neoadjuvant chemotherapy. Ther Adv Med Oncol 2020; 12:1758835920940886. [PMID: 32782487 PMCID: PMC7383657 DOI: 10.1177/1758835920940886] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 06/15/2020] [Indexed: 12/19/2022] Open
Abstract
Background: EPIC1 is an oncogenic long non-coding ribonucleic acid (RNA) that promotes cell growth and cell-cycle progression and inhibits apoptosis in several cancer cell lines. However, clinical studies on EPIC1 in breast cancer, specifically in the neoadjuvant setting, are relatively few. Methods: Patients treated with weekly paclitaxel–cisplatin-based neoadjuvant chemotherapy after core-needle biopsy were included in the study. Real-time quantitative polymerase chain reaction assays were performed to detect EPIC1 expression. Results: Among all patients included in this study (n = 111), higher EPIC1 expression was associated with estrogen receptor negativity, human epidermal growth factor receptor 2 positivity, higher Ki67 index, and higher histologic grade. Multivariate analysis suggested that EPIC1 expression was an independent predictive factor for pathological complete response, with a significant interaction between EPIC1 expression and age. The Kaplan–Meier Plotter dataset suggested that the EPIC1 high-expression group showed a worse 10-year distant metastasis-free survival and post-progression survival when compared with the EPIC1 low-expression group. The Cancer Genome Atlas dataset suggested that the overall survival in the EPIC1 high-expression group was inferior to that in the EPIC1 low-expression group, specifically in hormone receptor (HorR)-positive patients and patients aged <50 years. Pathway analysis revealed the top pathways that indicated the potential mechanisms of EPIC1 in chemoresistance, including the daunorubicin and doxorubicin metabolic processes. Conclusions: Our study suggests that EPIC1 may be a promising biomarker for both neoadjuvant chemosensitivity and long-term clinical outcomes in breast cancer, specifically in the HorR-positive premenopausal subgroup. It may also help identify candidate responders and determine treatment strategies.
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Affiliation(s)
- Yaqian Xu
- Department of Breast Surgery, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, People's Republic of China
| | - Yan Wang
- Department of Breast Surgery, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, People's Republic of China
| | - Chenwei Yuan
- Department of Breast Surgery, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, People's Republic of China
| | - Xiaonan Sheng
- Department of Breast Surgery, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, People's Republic of China
| | - Rui Sha
- Department of Breast Surgery, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, People's Republic of China
| | - Huijuan Dai
- Department of Breast Surgery, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, People's Republic of China
| | - Shan Zhang
- Department of Breast Surgery, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, People's Republic of China
| | - Yaohui Wang
- Department of Breast Surgery, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, People's Republic of China
| | - Yanping Lin
- Department of Breast Surgery, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, People's Republic of China
| | - Liheng Zhou
- Department of Breast Surgery, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, People's Republic of China
| | - Shuguang Xu
- Department of Breast Surgery, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, People's Republic of China
| | - Jie Zhang
- Department of Breast Surgery, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, People's Republic of China
| | - Wenjin Yin
- Department of Breast Surgery, Renji Hospital, School of Medicine, Shanghai Jiaotong University, No. 160 Pujian Road, Shanghai 200127, People's Republic of China
| | - Jinsong Lu
- Department of Breast Surgery, Renji Hospital, School of Medicine, Shanghai Jiaotong University, No. 160 Pujian Road, Shanghai 200127, People's Republic of China
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7
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Paine I, Posey JE, Grochowski CM, Jhangiani SN, Rosenheck S, Kleyner R, Marmorale T, Yoon M, Wang K, Robison R, Cappuccio G, Pinelli M, Magli A, Coban Akdemir Z, Hui J, Yeung WL, Wong BKY, Ortega L, Bekheirnia MR, Bierhals T, Hempel M, Johannsen J, Santer R, Aktas D, Alikasifoglu M, Bozdogan S, Aydin H, Karaca E, Bayram Y, Ityel H, Dorschner M, White JJ, Wilichowski E, Wortmann SB, Casella EB, Kitajima JP, Kok F, Monteiro F, Muzny DM, Bamshad M, Gibbs RA, Sutton VR, Van Esch H, Brunetti-Pierri N, Hildebrandt F, Brautbar A, Van den Veyver IB, Glass I, Lessel D, Lyon GJ, Lupski JR. Paralog Studies Augment Gene Discovery: DDX and DHX Genes. Am J Hum Genet 2019; 105:302-316. [PMID: 31256877 PMCID: PMC6698803 DOI: 10.1016/j.ajhg.2019.06.001] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 05/31/2019] [Indexed: 12/24/2022] Open
Abstract
Members of a paralogous gene family in which variation in one gene is known to cause disease are eight times more likely to also be associated with human disease. Recent studies have elucidated DHX30 and DDX3X as genes for which pathogenic variant alleles are involved in neurodevelopmental disorders. We hypothesized that variants in paralogous genes encoding members of the DExD/H-box RNA helicase superfamily might also underlie developmental delay and/or intellectual disability (DD and/or ID) disease phenotypes. Here we describe 15 unrelated individuals who have DD and/or ID, central nervous system (CNS) dysfunction, vertebral anomalies, and dysmorphic features and were found to have probably damaging variants in DExD/H-box RNA helicase genes. In addition, these individuals exhibit a variety of other tissue and organ system involvement including ocular, outer ear, hearing, cardiac, and kidney tissues. Five individuals with homozygous (one), compound-heterozygous (two), or de novo (two) missense variants in DHX37 were identified by exome sequencing. We identified ten total individuals with missense variants in three other DDX/DHX paralogs: DHX16 (four individuals), DDX54 (three individuals), and DHX34 (three individuals). Most identified variants are rare, predicted to be damaging, and occur at conserved amino acid residues. Taken together, these 15 individuals implicate the DExD/H-box helicases in both dominantly and recessively inherited neurodevelopmental phenotypes and highlight the potential for more than one disease mechanism underlying these disorders.
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Affiliation(s)
- Ingrid Paine
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Jennifer E Posey
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | | | - Shalini N Jhangiani
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Sarah Rosenheck
- Stanley Institute for Cognitive Genomics, Cold Spring Harbor Laboratory, NY 11724, USA
| | - Robert Kleyner
- Stanley Institute for Cognitive Genomics, Cold Spring Harbor Laboratory, NY 11724, USA
| | - Taylor Marmorale
- Stanley Institute for Cognitive Genomics, Cold Spring Harbor Laboratory, NY 11724, USA
| | - Margaret Yoon
- Stanley Institute for Cognitive Genomics, Cold Spring Harbor Laboratory, NY 11724, USA
| | - Kai Wang
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Reid Robison
- Utah Foundation for Biomedical Research, Salt Lake City, UT 84107, USA
| | - Gerarda Cappuccio
- Department of Translational Medicine, University of Naples "Federico II," 80131 Napoli, Italy; Telethon Institute of Genetics and Medicine, 80078 Pozzuoli, Italy
| | - Michele Pinelli
- Department of Translational Medicine, University of Naples "Federico II," 80131 Napoli, Italy; Telethon Institute of Genetics and Medicine, 80078 Pozzuoli, Italy
| | - Adriano Magli
- Department of Pediatric Ophthalmology, University of Salerno, 84081 Baronissi SA, Italy
| | - Zeynep Coban Akdemir
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Joannie Hui
- Department of Pediatrics, Prince of Wales Hospital, the Chinese University of Hong Kong, Hong Kong SAR, China
| | - Wai Lan Yeung
- Department of Pediatrics and Adolescent Medicine, Alice Ho Miu Ling Nethersole Hospital, Hong Kong SAR, China
| | - Bibiana K Y Wong
- Department of Obstetrics and Gynecology, Baylor College of Medicine, Houston, TX 77030, USA; The Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Lucia Ortega
- Medical Genetics Department, Cook Children's Hospital, Fort Worth, TX 76104, USA
| | - Mir Reza Bekheirnia
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Department of Pediatrics, Section of Pediatric Renal, Baylor College of Medicine, Houston, TX 77030, USA; Department of Genetics, Texas Children's Hospital, Houston, TX 76104, USA
| | - Tatjana Bierhals
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Maja Hempel
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Jessika Johannsen
- Department of Pediatrics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - René Santer
- Department of Pediatrics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Dilek Aktas
- DAMAGEN Genetic Diagnostic Center, 06690 Ankara, Turkey
| | | | - Sevcan Bozdogan
- Department of Medical Genetics, Cukurova University Faculty of Medicine, 01330 Adana, Turkey
| | - Hatip Aydin
- Department of Medical Genetics, Medical Faculty of Namik Kemal University, Tekirdag 59100, Turkey
| | - Ender Karaca
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Yavuz Bayram
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York City, NY 10029, USA
| | - Hadas Ityel
- Division of Nephrology, Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
| | - Michael Dorschner
- Center for Precision Diagnostics, University of Washington, Seattle, WA 98195, USA
| | - Janson J White
- Department of Pediatrics, University of Washington, Seattle, WA 98195, USA
| | - Ekkehard Wilichowski
- Department of Pediatrics and Pediatric Neurology, Georg-August-Universität Göttingen, 37075 Göttingen, Germany
| | - Saskia B Wortmann
- Institute of Human Genetics, Technical University München, 81675 Munich, Germany; Institute of Human Genetics, Helmholtz Zentrum Munchen, 85764 Neuherberg, Germany; University Children's Hospital, Paracelsus Medical University, 5020 Salsburg, Austria
| | - Erasmo B Casella
- Children's Institute, Hospital das Clinicas, University of Sao Paulo, 05405-000 Sao Paulo, Brazil
| | | | - Fernando Kok
- Mendelics Genomic Analysis, 04013-000 Sao Paulo, Brazil; Department of Neurology, University of Sao Paulo School of Medicine, 01246-903 Sao Paulo, Brazil
| | | | - Donna M Muzny
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Michael Bamshad
- Department of Pediatrics, University of Washington, Seattle, WA 98195, USA; Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA; Division of Genetic Medicine, University of Washington, Seattle, WA 98195, USA
| | - Richard A Gibbs
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - V Reid Sutton
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Hilde Van Esch
- Center for Human Genetics, University Hospitals Leuven, 3000 Leuven, Belgium
| | - Nicola Brunetti-Pierri
- Department of Translational Medicine, University of Naples "Federico II," 80131 Napoli, Italy; Telethon Institute of Genetics and Medicine, 80078 Pozzuoli, Italy
| | - Friedhelm Hildebrandt
- Division of Nephrology, Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
| | - Ariel Brautbar
- Medical Genetics Department, Cook Children's Hospital, Fort Worth, TX 76104, USA
| | - Ignatia B Van den Veyver
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Department of Obstetrics and Gynecology, Baylor College of Medicine, Houston, TX 77030, USA; The Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Ian Glass
- Division of Genetic Medicine, University of Washington, Seattle, WA 98195, USA
| | - Davor Lessel
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Gholson J Lyon
- Stanley Institute for Cognitive Genomics, Cold Spring Harbor Laboratory, NY 11724, USA; Utah Foundation for Biomedical Research, Salt Lake City, UT 84107, USA; Institute for Basic Research in Developmental Disabilities, Staten Island, NY 10314, USA
| | - James R Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA; Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA; Texas Children's Hospital, Houston, TX 77030, USA.
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8
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Tang J, Cui Q, Zhang D, Liao X, Zhu J, Wu G. An estrogen receptor (ER)-related signature in predicting prognosis of ER-positive breast cancer following endocrine treatment. J Cell Mol Med 2019; 23:4980-4990. [PMID: 31124293 PMCID: PMC6652714 DOI: 10.1111/jcmm.14338] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 02/26/2019] [Accepted: 04/04/2019] [Indexed: 12/26/2022] Open
Abstract
Quite a few estrogen receptor (ER)‐positive breast cancer patients receiving endocrine therapy are at risk of disease recurrence and death. ER‐related genes are involved in the progression and chemoresistance of breast cancer. In this study, we identified an ER‐related gene signature that can predict the prognosis of ER‐positive breast cancer patient receiving endocrine therapy. We collected RNA expression profiling from Gene Expression Omnibus database. An ER‐related signature was developed to separate patients into high‐risk and low‐risk groups. Patients in the low‐risk group had significantly better survival than those in the high‐risk group. ROC analysis indicated that this signature exhibited good diagnostic efficiency for the 1‐, 3‐ and 5‐year disease‐relapse events. Moreover, multivariate Cox regression analysis demonstrated that the ER‐related signature was an independent risk factor when adjusting for several clinical signatures. The prognostic value of this signature was validated in the validation sets. In addition, a nomogram was built and the calibration plots analysis indicated the good performance of this nomogram. In conclusion, combining with ER status, our results demonstrated that the ER‐related prognostic signature is a promising method for predicting the prognosis of ER‐positive breast cancer patients receiving endocrine therapy.
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Affiliation(s)
- Jianing Tang
- Department of Thyroid and Breast Surgery, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Qiuxia Cui
- Department of Thyroid and Breast Surgery, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Dan Zhang
- Department of Thyroid and Breast Surgery, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, China
| | - Xing Liao
- Department of Thyroid and Breast Surgery, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Jian Zhu
- Department of Thyroid and Breast Surgery, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Gaosong Wu
- Department of Thyroid and Breast Surgery, Zhongnan Hospital of Wuhan University, Wuhan, China
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9
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Milek M, Imami K, Mukherjee N, Bortoli FD, Zinnall U, Hazapis O, Trahan C, Oeffinger M, Heyd F, Ohler U, Selbach M, Landthaler M. DDX54 regulates transcriptome dynamics during DNA damage response. Genome Res 2017; 27:1344-1359. [PMID: 28596291 PMCID: PMC5538551 DOI: 10.1101/gr.218438.116] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 06/05/2017] [Indexed: 12/12/2022]
Abstract
The cellular response to genotoxic stress is mediated by a well-characterized network of DNA surveillance pathways. The contribution of post-transcriptional gene regulatory networks to the DNA damage response (DDR) has not been extensively studied. Here, we systematically identified RNA-binding proteins differentially interacting with polyadenylated transcripts upon exposure of human breast carcinoma cells to ionizing radiation (IR). Interestingly, more than 260 proteins, including many nucleolar proteins, showed increased binding to poly(A)+ RNA in IR-exposed cells. The functional analysis of DDX54, a candidate genotoxic stress responsive RNA helicase, revealed that this protein is an immediate-to-early DDR regulator required for the splicing efficacy of its target IR-induced pre-mRNAs. Upon IR exposure, DDX54 acts by increased interaction with a well-defined class of pre-mRNAs that harbor introns with weak acceptor splice sites, as well as by protein-protein contacts within components of U2 snRNP and spliceosomal B complex, resulting in lower intron retention and higher processing rates of its target transcripts. Because DDX54 promotes survival after exposure to IR, its expression and/or mutation rate may impact DDR-related pathologies. Our work indicates the relevance of many uncharacterized RBPs potentially involved in the DDR.
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Affiliation(s)
- Miha Milek
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin Institute for Medical Systems Biology, 13125 Berlin, Germany
| | - Koshi Imami
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin Institute for Medical Systems Biology, 13125 Berlin, Germany
| | - Neelanjan Mukherjee
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin Institute for Medical Systems Biology, 13125 Berlin, Germany
| | - Francesca De Bortoli
- Department of Biology, Chemistry, Pharmacy, Freie Universität Berlin, Institute of Chemistry and Biochemistry, Laboratory of RNA Biochemistry, 14195 Berlin, Germany
| | - Ulrike Zinnall
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin Institute for Medical Systems Biology, 13125 Berlin, Germany
| | - Orsalia Hazapis
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin Institute for Medical Systems Biology, 13125 Berlin, Germany
| | - Christian Trahan
- Institut de Recherches Cliniques de Montréal, H2W 1R7 Montréal, Quebec, Canada
- Département de Biochimie, Faculté de Médecine, Université de Montréal, H3A 1A3 Montréal, Quebec, Canada
| | - Marlene Oeffinger
- Institut de Recherches Cliniques de Montréal, H2W 1R7 Montréal, Quebec, Canada
- Département de Biochimie, Faculté de Médecine, Université de Montréal, H3A 1A3 Montréal, Quebec, Canada
- Faculty of Medicine, Division of Experimental Medicine, McGill University, H3T 1J4 Montréal, Quebec, Canada
| | - Florian Heyd
- Department of Biology, Chemistry, Pharmacy, Freie Universität Berlin, Institute of Chemistry and Biochemistry, Laboratory of RNA Biochemistry, 14195 Berlin, Germany
| | - Uwe Ohler
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin Institute for Medical Systems Biology, 13125 Berlin, Germany
- Institute of Biology, Humboldt-Universität zu Berlin, 10115 Berlin, Germany
- Department of Computer Science, Humboldt-Universität zu Berlin, 10099 Berlin, Germany
| | - Matthias Selbach
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin Institute for Medical Systems Biology, 13125 Berlin, Germany
- Charite-Universitätsmedizin Berlin, 10115 Berlin, Germany
| | - Markus Landthaler
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin Institute for Medical Systems Biology, 13125 Berlin, Germany
- IRI Life Sciences, Institute of Biology, Humboldt-Universität zu Berlin, 10115 Berlin, Germany
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10
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Inouye Y. [Structure and Function of the Nuclear Receptor Constitutive Androstane Receptor]. YAKUGAKU ZASSHI 2016; 136:297-308. [PMID: 26831808 DOI: 10.1248/yakushi.15-00215] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Animal defense mechanisms against both endogenous and exogenous toxic compounds function mainly through receptor-type transcription factors, including the constitutive androstane receptor (CAR). Following xenobiotic stimulation, CAR translocates into the nucleus and transactivates its target genes including oxygenic and conjugative enzymes and transporters in hepatocytes. We identified subcellular localization signals in the rat CAR: two nuclear localization signals (NLS1 and 2); two nuclear export signals (NES1 and 2); and a cytoplasmic retention region. The nuclear import of CAR is regulated by the importin-Ran system and microtubule network. Five splice variants (SV1-5) were identified in rat liver in addition to wild-type CAR. When expressed in immortalized cells, their artificial transcripts were inactive as transcription factors. A CAR mutant with three consecutive alanine residues inserted into the ligand-binding domain of CAR showed ligand-dependent activation of target genes in immortalized cells, which is in marked contrast to the constitutive transactivating nature of wild-type CAR. Using this assay system, androstenol and clotrimazole, both of which are inverse agonists of CAR, were classified as an antagonist and weak agonist, respectively. A member of the DEAD box DNA/RNA helicase family (DP97) and protein arginine methyltransferase 5 (PRMT5) were found to be gene (or promotor)-specific coactivators of CAR. The expression of the CAR gene might be under the control of clock genes mediated by the nuclear receptor Rev-erb-α.
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11
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Gee JMW, Nicholson RI, Barrow D, Dutkowski CM, Goddard L, Jordan NJ, McClelland RA, Knowlden JM, Francies HE, Hiscox SE, Hutcheson IR. Antihormone induced compensatory signalling in breast cancer: an adverse event in the development of endocrine resistance. Horm Mol Biol Clin Investig 2015; 5:67-77. [PMID: 25961242 DOI: 10.1515/hmbci.2011.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Accepted: 01/21/2011] [Indexed: 12/16/2022]
Abstract
Using MCF7 breast cancer cells, it has been shown that antihormones promote expression/activity of oestrogen-repressed tyrosine kinases, notably EGFR, HER2 and Src. These inductive events confer responsiveness to targeted inhibitors (e.g., gefitinib, trastuzumab, saracatinib). We observed that these antihormone-induced phenomena are common to ER+HER2- and ER+HER2+ breast cancer models in vitro, where targeting of EGFR, HER2 or Src alongside antihormone improves antitumour response and delays/prevents endocrine resistance. Such targeted inhibitors also subvert acquired endocrine resistant cells which retain increased EGFR, HER2 and Src (e.g., TAMR and FASR models derived after 6-12 months of tamoxifen or Faslodex treatment). Thus, antihormone-induced tyrosine kinases comprise "compensatory signalling" crucial in limiting maximal initial antihormone response and subsequently driving acquired resistance in vitro. However, despite such convincing preclinical findings from our group and others, clinical trials examining equivalent antigrowth factor strategies have proved relatively disappointing. Our new studies deciphering underlying causes reveal that further antihormone-promoted events could be pivotal in vivo. Firstly, Faslodex induces HER3 and HER4 which sensitise ER+ cells to heregulin, a paracrine growth factor that overcomes endocrine response and diminishes antitumour effect of agents targeting EGFR, HER2 or Src alongside antihormone. Secondly, extended antihormone exposure (experienced by ER+ cells prior to adjuvant clinical relapse) can "reprogramme" the compensatory kinase profile in vitro, hindering candidate antigrowth factor targeting of endocrine resistance. Faslodex resistant cells maintained with this antihormone for 3 years in vitro lose EGFR/HER2 dependency, gaining alternative mitogenic/invasion kinases. Deciphering these previously unrecognised antihormone-induced events could provide superior treatments to control endocrine relapse in the clinic.
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12
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Identification of telomere-associated molecules by engineered DNA-binding molecule-mediated chromatin immunoprecipitation (enChIP). Sci Rep 2013; 3:3171. [PMID: 24201379 PMCID: PMC3821016 DOI: 10.1038/srep03171] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Accepted: 10/24/2013] [Indexed: 11/09/2022] Open
Abstract
Biochemical analysis of molecular interactions in specific genomic regions requires their isolation while retaining molecular interactions in vivo. Here, we report isolation of telomeres by engineered DNA-binding molecule-mediated chromatin immunoprecipitation (enChIP) using a transcription activator-like (TAL) protein recognizing telomere repeats. Telomeres recognized by the tagged TAL protein were immunoprecipitated with an antibody against the tag and subjected to identification of telomere-binding molecules. enChIP-mass spectrometry (enChIP-MS) targeting telomeres identified known and novel telomere-binding proteins. The data have been deposited to the ProteomeXchange with identifier PXD000461. In addition, we showed that RNA associated with telomeres could be isolated by enChIP. Identified telomere-binding molecules may play important roles in telomere biology. enChIP using TAL proteins would be a useful tool for biochemical analysis of specific genomic regions of interest.
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13
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Robert F, Pelletier J. Perturbations of RNA helicases in cancer. WILEY INTERDISCIPLINARY REVIEWS-RNA 2013; 4:333-49. [PMID: 23658027 DOI: 10.1002/wrna.1163] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Helicases are implicated in most stages of the gene expression pathway, ranging from DNA replication, RNA transcription, splicing, RNA transport, ribosome biogenesis, mRNA translation, RNA storage and decay. These enzymes utilize energy derived from nucleotide triphosphate hydrolysis to remodel ribonucleoprotein complexes, RNA, or DNA and in this manner affect the information content or output of RNA. Several RNA helicases have been implicated in the oncogenic process--either through altered expression levels, mutations, or due to their role in pathways required for tumor initiation, progression, maintenance, or chemosensitivity. The purpose of this review is to highlight those RNA helicases for which there is significant evidence implicating them in cancer biology.
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Affiliation(s)
- Francis Robert
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada
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14
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Biarc J, Chalkley RJ, Burlingame AL, Bradshaw RA. Dissecting the roles of tyrosines 490 and 785 of TrkA protein in the induction of downstream protein phosphorylation using chimeric receptors. J Biol Chem 2013; 288:16606-16618. [PMID: 23589303 DOI: 10.1074/jbc.m113.475285] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Receptor tyrosine kinases generally act by forming phosphotyrosine-docking sites on their own endodomains that propagate signals through cascades of post-translational modifications driven by the binding of adaptor/effector proteins. The pathways that are stimulated in any given receptor tyrosine kinase are a function of the initial docking sites that are activated and the availability of downstream participants. In the case of the Trk receptors, which are activated by nerve growth factor, there are only two established phosphotyrosine-docking sites (Tyr-490 and Tyr-785 on TrkA) that are known to be directly involved in signal transduction. Taking advantage of this limited repertoire of docking sites and the availability of PC12 cell lines stably transfected with chimeric receptors composed of the extracellular domain of the PDGF receptor and the transmembrane and intracellular domains of TrkA, the downstream TrkA-induced phosphoproteome was assessed for the "native" receptor and mutants lacking Tyr-490 or both Tyr-490 and Tyr-785. Basal phosphorylation levels were compared with those formed after 20 min of stimulation with PDGF. Several thousand phosphopeptides were identified after TiO2 enrichment, and many were up- or down-regulated by receptor activation. The modified proteins in the native sample contained many of the well established participants in TrkA signaling. The results from the mutant receptors allowed grouping of these downstream targets by their dependence on the two characterized docking site(s). A clear subset that was not dependent on either Tyr-490 or Tyr-785 emerged, providing direct evidence that there are other sites on TrkA that are involved in downstream signaling.
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Affiliation(s)
- Jordane Biarc
- Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94158
| | - Robert J Chalkley
- Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94158.
| | - A L Burlingame
- Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94158
| | - Ralph A Bradshaw
- Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94158; Department of Physiology and Biophysics, University of California, Irvine, California 92697
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15
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Zhan R, Yamamoto M, Ueki T, Yoshioka N, Tanaka K, Morisaki H, Seiwa C, Yamamoto Y, Kawano H, Tsuruo Y, Watanabe K, Asou H, Aiso S. A DEAD-box RNA helicase Ddx54 protein in oligodendrocytes is indispensable for myelination in the central nervous system. J Neurosci Res 2012; 91:335-48. [PMID: 23239230 DOI: 10.1002/jnr.23162] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2012] [Revised: 09/22/2012] [Accepted: 10/02/2012] [Indexed: 02/05/2023]
Abstract
We recently reported that a new monoclonal antibody, 4F2, which labels oligodendroglial lineage cells, recognizes a DEAD-box RNA helicase Ddx54 and that Ddx54 binds to myelin basic protein (MBP) in brain and cultured oligodendrocytes. To elucidate the biological function of Ddx54, we generated a recombinant adenovirus, Ad-shRNA:Ddx54, expressing a short hairpin RNA to silence endogenous Ddx54 protein. The virus was intraventricularly injected into the brains of mice on postnatal day (PD) 2. The brains at PD 9 were then analyzed by immunohistochemistry. In untreated normal brain sections, as well as control brains that had been injected with Ad-β-Gal, myelination of axons occurred in the corpus callosum with filamentous patterns of immunosignals of myelin-associated glycoprotein (MAG) and MBP. In Ad-shRNA:Ddx54-injected brain, substantial amounts of MAG and MBP immunosignals were present, but MBP immunosignals accumulated in the subplate layer and did not intrude into the emerging white matter. Immunoblot analysis revealed that Ddx54 knockdown caused a significant decrease in the level of 21.5 kDa MBP isoform and Ddx54, but the amount of Olig2; 2',3'-cyclic nucleotide 3' phosphodiesterase; MAG; three MBP isoforms (14, 17.5, and 18 kDa); and QKI-5, QKI-6, and QKI-7 proteins remained unchanged. Transfection of the Ddx54 expression vector into luciferase reporter-introduced neuroepithelial cells resulted in upregulated MBP promoter activity. Immunoprecipitation of Ddx54 protein in MBP-transfected HEK293 cells indicated that Ddx54 may directly interact with MBP mRNA. These results suggest that Ddx54 protein play an important role in central nervous system myelination, presumably in myelin sheath formation after the differentiation of oligodendrocytes.
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Affiliation(s)
- Rui Zhan
- Center for Kampo Medicine, Keio University School of Medicine, Tokyo, Japan
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16
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Kanno Y, Serikawa T, Inajima J, Inouye Y. DP97, a DEAD box DNA/RNA helicase, is a target gene-selective co-regulator of the constitutive androstane receptor. Biochem Biophys Res Commun 2012; 426:38-42. [PMID: 22910411 DOI: 10.1016/j.bbrc.2012.08.027] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Accepted: 08/07/2012] [Indexed: 01/09/2023]
Abstract
The constitutive androstane receptor (CAR) plays a key role in the expression of xenobiotic/steroid and drug metabolizing enzymes and their transporters. In this study, we demonstrated that DP97, a member of the DEAD box DNA/RNA helicase protein family, is a novel CAR-interacting protein. Using HepG2 cells expressing human CAR in the presence of tetracycline, we showed that knockdown of DP97 with small interfering RNAs suppressed tetracycline-inducible mRNA expression of CYP2B6 and UGT1A1 but not CYP3A4. Thus, DP97 was found to be a gene (or promoter)-selective co-activator for hCAR. DP97-mediated CAR transactivation was synergistically enhanced by the co-expression of SRC-1 or PGC1α, therefore it might act as mediator between hCAR and appropriate co-activators.
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Affiliation(s)
- Yuichiro Kanno
- Faculty of Pharmaceutical Sciences, Toho University, Chiba, Japan.
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17
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Ivanova M, Abner S, Pierce W, Klinge C. Ligand-dependent differences in estrogen receptor beta-interacting proteins identified in lung adenocarcinoma cells corresponds to estrogenic responses. Proteome Sci 2011; 9:60. [PMID: 21951318 PMCID: PMC3192725 DOI: 10.1186/1477-5956-9-60] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Accepted: 09/27/2011] [Indexed: 12/13/2022] Open
Abstract
Background A recent epidemiological study demonstrated a reduced risk of lung cancer mortality in breast cancer patients using antiestrogens. These and other data implicate a role for estrogens in lung cancer, particularly nonsmall cell lung cancer (NSCLC). Approximately 61% of human NSCLC tumors express nuclear estrogen receptor β (ERβ); however, the role of ERβ and estrogens in NSCLC is likely to be multifactorial. Here we tested the hypothesis that proteins interacting with ERβ in human lung adenocarcinoma cells that respond proliferatively to estradiol (E2) are distinct from those in non-E2-responsive cells. Methods FLAG affinity purification of FLAG-ERβ-interacting proteins was used to isolate ERβ-interacting proteins in whole cell extracts from E2 proliferative H1793 and non-E2-proliferative A549 lung adenocarcinoma cell lines. Following trypsin digestion, proteins were identified using liquid chromatography electrospray ionization tandem mass spectrometry (LC-MS/MS). Proteomic data were analyzed using Ingenuity Pathway Analysis. Select results were confirmed by coimmunoprecipitation. Results LC-MS/MS identified 27 non-redundant ERβ-interacting proteins. ERβ-interacting proteins included hsp70, hsp60, vimentin, histones and calmodulin. Ingenuity Pathway Analysis of the ERβ-interacting proteins revealed differences in molecular and functional networks between H1793 and A549 lung adenocarcinoma cells. Coimmunoprecipitation experiments in these and other lung adenocarcinoma cells confirmed that ERβ and EGFR interact in a gender-dependent manner and in response to E2 or EGF. BRCA1 interacted with ERβ in A549 cell lines and in human lung adenocarcinoma tumors, but not normal lung tissue. Conclusion Our results identify specific differences in ERβ-interacting proteins in lung adenocarcinoma cells corresponding to ligand-dependent differences in estrogenic responses.
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Affiliation(s)
- Mm Ivanova
- Department of Biochemistry & Molecular Biology, Center for Genetics and Molecular Medicine, University of Louisville School of Medicine, Louisville, KY, 40292 USA.
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18
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Ueki T, Tsuruo Y, Yamamoto Y, Yoshimura K, Takanaga H, Seiwa C, Motojima K, Asou H, Yamamoto M. A new monoclonal antibody, 4F2, specific for the oligodendroglial cell lineage, recognizes ATP-dependent RNA helicase Ddx54: possible association with myelin basic protein. J Neurosci Res 2011; 90:48-59. [PMID: 21932369 DOI: 10.1002/jnr.22736] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Revised: 06/07/2011] [Accepted: 06/10/2011] [Indexed: 11/07/2022]
Abstract
Recent research in neural development has highlighted the importance of markers to discriminate phenotypic alterations of neural cells at various developmental stages. We isolated a new monoclonal antibody, 4F2, which was shown to be specific for an oligodendrocyte lineage. In primary cultures of oligodendroglial and mixed neural cells, the 4F2 antibody labeled a large proportion of Sox2(+) , Sox10(+) , A2B5(+) , NG2(+) , Olig2(+) , O4(+) , and myelin basic protein (MBP)(+) cells but did not label any GFAP(+) or NeuN(+) cells. In immunohistochemisty of rat embryos, the 4F2 antibody labeled a portion of neuroepithelial cells of the neural tube at embryonic day 9. The 4F2-positive cells were located initially in the ventricular zone as Musashi1(+) Tuj1(-) populations and distributed throughout the striatum; thereafter, they populated the whole brain and spinal cord. These cells showed ramified processes during embryonal development. The 4F2 antigen was associated with all four isoforms of MBP in coimmunoprecipitation experiments using brain homogenates or cell lysates of cultured oligodendrocytes. Immunoscreening of a brain cDNA library identified the antigen as DEAD (Asp-Glu-Ala-Asp) box polypeptide 54 (Ddx54), a member of the DEAD box family of RNA helicases involved in RNA metabolism, transcription, and translation. Cotransfection of the Ddx54 gene with MBP isoform genes increased the nuclear localization of the 21.5-kDa MBP isoform, which has been reported to function as a nuclear signal transduction molecule. These data indicate that Ddx54 might be not only a useful marker for investigating the ontogeny of oligodendrocytes but also an important factor in oligodendrocyte differentiation and myelination.
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Affiliation(s)
- Toshiyuki Ueki
- Department of Neuro-Glia Cell Biology, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
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19
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Stender JD, Stossi F, Funk CC, Charn TH, Barnett DH, Katzenellenbogen BS. The estrogen-regulated transcription factor PITX1 coordinates gene-specific regulation by estrogen receptor-alpha in breast cancer cells. Mol Endocrinol 2011; 25:1699-709. [PMID: 21868451 DOI: 10.1210/me.2011-0102] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The estrogen receptor α (ERα) is a master regulator of gene expression and works along with cooperating transcription factors in mediating the actions of the hormone estradiol (E2) in ER-positive tissues and breast tumors. Here, we report that expression of paired-like homeodomain transcription factor (PITX1), a tumor suppressor and member of the homeobox family of transcription factors, is robustly up-regulated by E2 in several ERα-positive breast cancer cell lines via ERα-dependent interaction between the proximal promoter and an enhancer region 5' upstream of the PITX1 gene. Overexpression of PITX1 selectively inhibited the transcriptional activity of ERα and ERβ, while enhancing the activities of the glucocorticoid receptor and progesterone receptor. Reduction of PITX1 by small interfering RNA enhanced ERα-dependent transcriptional regulation of a subset of ERα target genes. The consensus PITX1 binding motif was found to be present in 28% of genome-wide ERα binding sites and was in close proximity to estrogen response elements in a subset of ERα binding sites, and E2 treatment enhanced PITX1 as well as ERα recruitment to these binding sites. These studies identify PITX1 as a new ERα transcriptional target that acts as a repressor to coordinate and fine tune target-specific, ERα-mediated transcriptional activity in human breast cancer cells.
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Affiliation(s)
- Joshua D Stender
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801-3704, USA
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20
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Tarallo R, Bamundo A, Nassa G, Nola E, Paris O, Ambrosino C, Facchiano A, Baumann M, Nyman TA, Weisz A. Identification of proteins associated with ligand-activated estrogen receptor α in human breast cancer cell nuclei by tandem affinity purification and nano LC-MS/MS. Proteomics 2010; 11:172-9. [PMID: 21182205 DOI: 10.1002/pmic.201000217] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2010] [Revised: 08/03/2010] [Accepted: 10/04/2010] [Indexed: 01/14/2023]
Abstract
Estrogen receptor α (ER-α) is a key mediator of estrogen actions in breast cancer (BC) cells. Understanding the effects of ligand-activated ER-α in target cells requires identification of the molecular partners acting in concert with this nuclear receptor to transduce the hormonal signal. We applied tandem affinity purification (TAP), glycerol gradient centrifugation and MS analysis to isolate and identify proteins interacting with ligand-activated ER-α in MCF-7 cell nuclei. This led to the identification of 264 ER-associated proteins, whose functions highlight the hinge role of ER-α in the coordination of multiple hormone-regulated nuclear processes in BC cells.
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Affiliation(s)
- Roberta Tarallo
- Department of General Pathology, Second University of Naples, Napoli, Italy
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21
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Genome-wide analysis of estrogen receptor alpha DNA binding and tethering mechanisms identifies Runx1 as a novel tethering factor in receptor-mediated transcriptional activation. Mol Cell Biol 2010; 30:3943-55. [PMID: 20547749 DOI: 10.1128/mcb.00118-10] [Citation(s) in RCA: 163] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Nuclear receptor estrogen receptor alpha (ER alpha) controls the expression of hundreds of genes responsible for target cell phenotypic properties, but the relative importance of direct versus tethering mechanisms of DNA binding has not been established. In this first report, we examine the genome-wide chromatin localization of an altered-specificity mutant ER with a DNA binding domain deficient in binding to estrogen response element (ERE)-containing DNA (DBDmut ER) versus wild-type ER alpha. Using high-throughput sequencing of ER chromatin immunoprecipitations (ChIP-Seq) and mRNA transcriptional profiling, we show that direct ERE binding is required for most of (75%) estrogen-dependent gene regulation and 90% of hormone-dependent recruitment of ER to genomic binding sites. De novo motif analysis of the chromatin binding regions in MDA-MB-231 human breast cancer cells defined unique transcription factor profiles responsible for genes regulated through tethering versus direct ERE binding, with Runx motifs enriched in ER-tethered sites. We confirmed a role for Runx1 in mediating ER alpha genomic recruitment and regulation of tethering genes. Our findings delineate the contributions of direct receptor ERE binding versus binding through response elements for other transcription factors in chromatin localization and ER-dependent gene regulation, paradigms likely to underlie the gene regulatory actions of other nuclear receptors as well.
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22
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Botlagunta M, Vesuna F, Mironchik Y, Raman A, Lisok A, Winnard P, Mukadam S, Van Diest P, Chen JH, Farabaugh P, Patel AH, Raman V. Oncogenic role of DDX3 in breast cancer biogenesis. Oncogene 2008; 27:3912-22. [PMID: 18264132 DOI: 10.1038/onc.2008.33] [Citation(s) in RCA: 163] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Benzo[a]pyrene diol epoxide (BPDE), the active metabolite of benzo[a]pyrene present in tobacco smoke, is a major cancer-causing compound. To evaluate the effects of BPDE on human breast epithelial cells, we exposed an immortalized human breast cell line, MCF 10A, to BPDE and characterized the gene expression pattern. Of the differential genes expressed, we found consistent activation of DDX3, a member of the DEAD box RNA helicase family. Overexpression of DDX3 in MCF 10A cells induced an epithelial-mesenchymal-like transformation, exhibited increased motility and invasive properties, and formed colonies in soft-agar assays. Besides the altered phenotype, MCF 10A-DDX3 cells repressed E-cadherin expression as demonstrated by both immunoblots and by E-cadherin promoter-reporter assays. In addition, an in vivo association of DDX3 and the E-cadherin promoter was demonstrated by chromatin immunoprecipitation assays. Collectively, these results demonstrate that the activation of DDX3 by BPDE, can promote growth, proliferation and neoplastic transformation of breast epithelial cells.
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Affiliation(s)
- M Botlagunta
- Department of Radiology and Radiological Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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Shin S, Janknecht R. Concerted activation of the Mdm2 promoter by p72 RNA helicase and the coactivators p300 and P/CAF. J Cell Biochem 2007; 101:1252-65. [PMID: 17226766 DOI: 10.1002/jcb.21250] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A scarcely studied and under-recognized feature of RNA helicases is their ability to regulate gene transcription. In particular, very little is known about the role of p72 RNA helicase in gene regulation. Here, we have analyzed how this helicase may enhance promoter activity. We demonstrate that p72 RNA helicase forms complexes with the homologous coactivators p300 and CBP in vitro and in vivo, especially leading to an enhancement of the transactivation potential of their C-termini. In addition, we show that the p300/CBP-associated protein (P/CAF) also interacts with p72 RNA helicase, and both this interaction and the binding to p300/CBP are mediated by the N-terminal 63 amino acids of p72 RNA helicase. p300, P/CAF and p72 RNA helicase synergize to stimulate selected promoters, including the Mdm2 one. Notably, downregulation of p72 RNA helicase leads to reduced Mdm2 transcription. Furthermore, our data suggest that p72 RNA helicase activates the Mdm2 promoter in a p53 dependent and independent manner. Collectively, our results have unraveled a mechanism of how p72 RNA helicase can regulate gene transcription, namely by cooperating with p300/CBP and P/CAF. Thereby, p72 RNA helicase may not only be involved in the p53-Mdm2 regulatory loop, but also profoundly impact on the transcriptome through various CBP/p300 and P/CAF interacting proteins.
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Affiliation(s)
- Sook Shin
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA
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24
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Heldring N, Pike A, Andersson S, Matthews J, Cheng G, Hartman J, Tujague M, Ström A, Treuter E, Warner M, Gustafsson JA. Estrogen receptors: how do they signal and what are their targets. Physiol Rev 2007; 87:905-31. [PMID: 17615392 DOI: 10.1152/physrev.00026.2006] [Citation(s) in RCA: 1245] [Impact Index Per Article: 73.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
During the past decade there has been a substantial advance in our understanding of estrogen signaling both from a clinical as well as a preclinical perspective. Estrogen signaling is a balance between two opposing forces in the form of two distinct receptors (ER alpha and ER beta) and their splice variants. The prospect that these two pathways can be selectively stimulated or inhibited with subtype-selective drugs constitutes new and promising therapeutic opportunities in clinical areas as diverse as hormone replacement, autoimmune diseases, prostate and breast cancer, and depression. Molecular biological, biochemical, and structural studies have generated information which is invaluable for the development of more selective and effective ER ligands. We have also become aware that ERs do not function by themselves but require a number of coregulatory proteins whose cell-specific expression explains some of the distinct cellular actions of estrogen. Estrogen is an important morphogen, and many of its proliferative effects on the epithelial compartment of glands are mediated by growth factors secreted from the stromal compartment. Thus understanding the cross-talk between growth factor and estrogen signaling is essential for understanding both normal and malignant growth. In this review we focus on several of the interesting recent discoveries concerning estrogen receptors, on estrogen as a morphogen, and on the molecular mechanisms of anti-estrogen signaling.
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Affiliation(s)
- Nina Heldring
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
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25
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Abstract
RNA interference (RNAi) is a naturally occurring cellular defense mechanism against viral infections and transposon invasion. Short double-stranded RNA molecules, so-called small-interfering (si)RNAs, bind their complementary mRNA leading to the mRNA's degradation. During the past few years, RNAi has become a valuable tool for transient as well as stable repression of gene expression rendering the time-consuming production of knockout animals superfluous. In this chapter the usability of the RNAi technology in cancer research will be described, focusing on the application of large-scale screens for identification of new components in cancer-relevant signal pathways (e.g., p53, RAS). The screens are especially helpful in the detection of potential anticancer drug targets or siRNAs with therapeutic potential.
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Affiliation(s)
- Uta Fuchs
- Dr. von Haunersches Kinderspital, Ludwig Maximilians Universität München, München, Germany
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26
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Linder P. Dead-box proteins: a family affair--active and passive players in RNP-remodeling. Nucleic Acids Res 2006; 34:4168-80. [PMID: 16936318 PMCID: PMC1616962 DOI: 10.1093/nar/gkl468] [Citation(s) in RCA: 347] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2006] [Revised: 06/19/2006] [Accepted: 06/20/2006] [Indexed: 11/23/2022] Open
Abstract
DEAD-box proteins are characterized by nine conserved motifs. According to these criteria, several hundreds of these proteins can be identified in databases. Many different DEAD-box proteins can be found in eukaryotes, whereas prokaryotes have small numbers of different DEAD-box proteins. DEAD-box proteins play important roles in RNA metabolism, and they are very specific and cannot mutually be replaced. In vitro, many DEAD-box proteins have been shown to have RNA-dependent ATPase and ATP-dependent RNA helicase activities. From the genetic and biochemical data obtained mainly in yeast, it has become clear that these proteins play important roles in remodeling RNP complexes in a temporally controlled fashion. Here, I shall give a general overview of the DEAD-box protein family.
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Affiliation(s)
- Patrick Linder
- Department of Microbiology and Molecular Medicine, CMU 1, rue Michel Servet, CH-1211 Genève 4, Switzerland.
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27
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Fuller-Pace FV. DExD/H box RNA helicases: multifunctional proteins with important roles in transcriptional regulation. Nucleic Acids Res 2006; 34:4206-15. [PMID: 16935882 PMCID: PMC1616952 DOI: 10.1093/nar/gkl460] [Citation(s) in RCA: 338] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The DExD/H box family of proteins includes a large number of proteins that play important roles in RNA metabolism. Members of this family have been shown to act as RNA helicases or unwindases, using the energy from ATP hydrolysis to unwind RNA structures or dissociate RNA–protein complexes in cellular processes that require modulation of RNA structures. However, it is clear that several members of this family are multifunctional and, in addition to acting as RNA helicases in processes such as pre-mRNA processing, play important roles in transcriptional regulation. In this review I shall concentrate on RNA helicase A (Dhx9), DP103 (Ddx20), p68 (Ddx5) and p72 (Ddx17), proteins for which there is a strong body of evidence showing that they play important roles in transcription, often as coactivators or corepressors through their interaction with key components of the transcriptional machinery, such as CREB-binding protein, p300, RNA polymerase II and histone deacetylases.
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Affiliation(s)
- Frances V Fuller-Pace
- Cancer Biology Group, Division of Pathology and Neuroscience, University of Dundee, Ninewells Hospital and Medical School, Dundee DD1 9SY, UK.
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28
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Ascenzi P, Bocedi A, Marino M. Structure-function relationship of estrogen receptor alpha and beta: impact on human health. Mol Aspects Med 2006; 27:299-402. [PMID: 16914190 DOI: 10.1016/j.mam.2006.07.001] [Citation(s) in RCA: 361] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
17Beta-estradiol (E2) controls many aspects of human physiology, including development, reproduction and homeostasis, through regulation of the transcriptional activity of its cognate receptors (ERs). The crystal structures of ERs with agonists and antagonists and the use of transgenic animals have revealed much about how hormone binding influences ER conformation(s) and how this conformation(s), in turn, influences the interaction of ERs with co-activators or co-repressors and hence determines ER binding to DNA and cellular outcomes. This information has helped to shed light on the connection between E2 and the development or progression of numerous diseases. Current therapeutic strategy in the treatment of E2-related pathologies relies on the modulation of ER trancriptional activity by anti-estrogens; however, data accumulated during the last five years reveal that ER activities are not only restricted to the nucleus. ERs are very mobile proteins continuously shuttling between protein targets located within various cellular compartments (e.g., membrane, nucleus). This allows E2 to generate different and synergic signal transduction pathways (i.e., non-genomic and genomic) which provide plasticity for cell response to E2. Understanding the structural basis and the molecular mechanisms by which ER transduce E2 signals in target cells will allow to create new pharmacologic therapies aimed at the treatment of a variety of human diseases affecting the cardiovascular system, the reproductive system, the skeletal system, the nervous system, the mammary gland, and many others.
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Affiliation(s)
- Paolo Ascenzi
- Department of Biology, University Roma Tre, Viale Guglielmo Marconi 446, I-00146 Roma, Italy
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29
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Soyal S, Krempler F, Oberkofler H, Patsch W. PGC-1alpha: a potent transcriptional cofactor involved in the pathogenesis of type 2 diabetes. Diabetologia 2006; 49:1477-88. [PMID: 16752166 DOI: 10.1007/s00125-006-0268-6] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2005] [Accepted: 02/03/2006] [Indexed: 12/24/2022]
Abstract
Data derived from several recent studies implicate peroxisome proliferator-activated receptor-gamma coactivator-1alpha (PGC-1alpha) in the pathogenesis of type 2 diabetes. Lacking DNA binding activity itself, PGC-1alpha is a potent, versatile regulator of gene expression that co-ordinates the activation and repression of transcription via protein-protein interactions with specific, as well as more general, factors contained within the basal transcriptional machinery. PGC-1alpha is suggested to play a pivotal role in the control of genetic pathways that result in homeostatic glucose utilisation in liver and muscle, beta cell insulin secretion and mitochondrial biogenesis. This review focuses on the role of PGC-1alpha in glucose metabolism and considers how PGC-1alpha links cellular glucose metabolism, insulin sensitivity and mitochondrial function, and why defects in PGC-1alpha expression and regulation may contribute to the pathophysiology of type 2 diabetes in humans.
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Affiliation(s)
- S Soyal
- Department of Internal Medicine, Krankenhaus Hallein, 5400, Hallein, Austria
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30
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Ding X, Saxena NK, Lin S, Gupta NA, Gupta N, Anania FA. Exendin-4, a glucagon-like protein-1 (GLP-1) receptor agonist, reverses hepatic steatosis in ob/ob mice. Hepatology 2006; 43:173-81. [PMID: 16374859 PMCID: PMC2925424 DOI: 10.1002/hep.21006] [Citation(s) in RCA: 430] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Nonalcoholic fatty liver disease (NAFLD) represents a burgeoning problem in hepatology, and is associated with insulin resistance. Exendin-4 is a peptide agonist of the glucagon-like peptide (GLP) receptor that promotes insulin secretion. The aim of this study was to determine whether administration of Exendin-4 would reverse hepatic steatosis in ob/ob mice. Ob/ob mice, or their lean littermates, were treated with Exendin-4 [10 microg/kg or 20 microg/kg] for 60 days. Serum was collected for measurement of insulin, adiponectin, fasting glucose, lipids, and aminotransferase concentrations. Liver tissue was procured for histological examination, real-time RT-PCR analysis and assay for oxidative stress. Rat hepatocytes were isolated and treated with GLP-1. Ob/ob mice sustained a reduction in the net weight gained during Exendin-4 treatment. Serum glucose and hepatic steatosis was significantly reduced in Exendin-4 treated ob/ob mice. Exendin-4 improved insulin sensitivity in ob/ob mice, as calculated by the homeostasis model assessment. The measurement of thiobarbituric reactive substances as a marker of oxidative stress was significantly reduced in ob/ob-treated mice with Exendin-4. Finally, GLP-1-treated hepatocytes resulted in a significant increase in cAMP production as well as reduction in mRNA expression of stearoyl-CoA desaturase 1 and genes associated with fatty acid synthesis; the converse was true for genes associated with fatty acid oxidation. In conclusion, Exendin-4 appears to effectively reverse hepatic steatosis in ob/ob mice by improving insulin sensitivity. Our data suggest that GLP-1 proteins in liver have a novel direct effect on hepatocyte fat metabolism.
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Affiliation(s)
- Xiaokun Ding
- Division of Digestive Diseases, Emory University School of Medicine, Atlanta, GA 30322, USA
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31
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Satoh JI, Nanri Y, Yamamura T. Rapid identification of 14-3-3-binding proteins by protein microarray analysis. J Neurosci Methods 2005; 152:278-88. [PMID: 16260042 DOI: 10.1016/j.jneumeth.2005.09.015] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2005] [Revised: 09/19/2005] [Accepted: 09/26/2005] [Indexed: 12/22/2022]
Abstract
The 14-3-3 protein family consists of acidic 30-kDa proteins composed of seven isoforms in mammalian cells, expressed abundantly in neurons and glial cells of the central nervous system (CNS). The 14-3-3 isoforms form a dimer that acts as a molecular adaptor interacting with key signaling components involved in cell proliferation, transformation, and apoptosis. Until present, more than 300 proteins have been identified as 14-3-3-binding partners, although most of previous studies focused on a limited range of 14-3-3-interacting proteins. Here, we studied a comprehensive profile of 14-3-3-binding proteins by analyzing a high-density protein microarray using recombinant human 14-3-3 epsilon protein as a probe. Among 1752 proteins immobilized on the microarray, 20 were identified as 14-3-3 interactors, most of which were previously unreported 14-3-3-binding partners. However, 11 known 14-3-3-binding proteins, including keratin 18 (KRT18) and mitogen-activated protein kinase-activated protein kinase 2 (MAPKAPK2), were not identified as a 14-3-3-binding protein. The specific binding to 14-3-3 of EAP30 subunit of ELL complex (EAP30), dead box polypeptide 54 (DDX54), and src homology three (SH3) and cysteine rich domain (STAC) was verified by immunoprecipitation analysis of the recombinant proteins expressed in HEK293 cells. These results suggest that protein microarray is a powerful tool for rapid and comprehensive profiling of 14-3-3-binding proteins.
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Affiliation(s)
- Jun-ichi Satoh
- Department of Immunology, National Institute of Neuroscience, NCNP, 4-1-1 Ogawahigashi, Kodaira, Tokyo 187-8502, Japan.
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32
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Auboeuf D, Dowhan DH, Dutertre M, Martin N, Berget SM, O'Malley BW. A subset of nuclear receptor coregulators act as coupling proteins during synthesis and maturation of RNA transcripts. Mol Cell Biol 2005; 25:5307-16. [PMID: 15964789 PMCID: PMC1156981 DOI: 10.1128/mcb.25.13.5307-5316.2005] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Affiliation(s)
- Didier Auboeuf
- INSERM U685/AVENIR, Centre G. Hayem, Hôpital Saint Louis, Paris, France.
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33
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Zubairy S, Oesterreich S. Estrogen-repressed genes -- key mediators of estrogen action? Breast Cancer Res 2005; 7:163-4. [PMID: 15987468 PMCID: PMC1175077 DOI: 10.1186/bcr1271] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Simeen Zubairy
- Department of Medicine and Molecular and Cellular Biology, Breast Center, Baylor College of Medicine, Houston, Texas, USA
| | - Steffi Oesterreich
- Department of Medicine and Molecular and Cellular Biology, Breast Center, Baylor College of Medicine, Houston, Texas, USA
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34
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Rai D, Frolova A, Frasor J, Carpenter AE, Katzenellenbogen BS. Distinctive actions of membrane-targeted versus nuclear localized estrogen receptors in breast cancer cells. Mol Endocrinol 2005; 19:1606-17. [PMID: 15831524 DOI: 10.1210/me.2004-0468] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Estrogens regulate multiple activities in breast cancer cells, including proliferation. Whereas these hormones are most commonly known to regulate gene transcription through direct interaction with estrogen receptors (ERs) and with specific DNA sequences of target genes, recent studies show that ER also activates a number of rapid signaling events that are initiated at the cell membrane. To study the membrane-initiated effects of estrogen and separate them from the activities initiated by the nuclear localized ER in human breast cancer cells, we generated MDA-MB-231 breast cancer cell lines that have stably integrated either the wild-type nuclear form of ER (WT-ER) or a modified, membrane-targeted ER (MT-ER) that lacks a nuclear localization sequence and is dually acylated with a myristoylation sequence at the N terminus and a palmitoylation sequence at the C terminus. We demonstrate that MT-ER is membrane localized in the absence of estradiol (E2), showing punctate membrane and cytoplasmic speckles after E2 exposure. In contrast to WT-ER, MT-ER was not down-regulated by E2 or by antiestrogen ICI 182,780 exposure, and MT-ER failed to regulate endogenous E2-responsive genes highly up-regulated by WT-ER. Cells expressing MT-ER showed a greater serum response element-mediated transcriptional response that was partially inhibited by antiestrogen ICI 182,780. The MT-ER and WT-ER differentially altered ERK1/2 and Akt activities and the proliferation of breast cancer cells in response to E2. Hence, this study reveals distinct actions of the MT-ER vs. the WT-ER in effecting estrogen actions in breast cancer cells.
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Affiliation(s)
- Deshanie Rai
- Department of Molecular and Integrative Physiology, University of Illinois and College of Medicine, 524 Burrill Hall, 407 South Goodwin Avenue, Urbana, Illinois 61801-3704, USA
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35
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Lee MB, Lebedeva LA, Suzawa M, Wadekar SA, Desclozeaux M, Ingraham HA. The DEAD-box protein DP103 (Ddx20 or Gemin-3) represses orphan nuclear receptor activity via SUMO modification. Mol Cell Biol 2005; 25:1879-90. [PMID: 15713642 PMCID: PMC549377 DOI: 10.1128/mcb.25.5.1879-1890.2005] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Structural analysis of nuclear receptor subfamily V orphan nuclear receptors suggests that ligand-independent mechanisms must regulate this subclass of receptors. Here, we report that steroidogenic factor 1 (SF-1) and liver receptor homolog 1 are repressed via posttranslational SUMO modification at conserved lysines within the hinge domain. Indeed, mutating these lysines or adding the SUMO isopeptidase SENP1 dramatically increased both native and Gal4-chimera receptor activities. The mechanism by which SUMO conjugation attenuates SF-1 activity was found to be largely histone deacetylase independent and was unaffected by the AF2 corepressor Dax1. Instead, our data suggest that SUMO-mediated repression involves direct interaction of the DEAD-box protein DP103 with sumoylated SF-1. Of potential E3-SUMO ligase candidates, PIASy and PIASxalpha strongly promoted SF-1 sumoylation, and addition of DP103 enhanced both PIAS-dependent receptor sumoylation and SF-1 relocalization to discrete nuclear bodies. Taken together, we propose that DEAD-box RNA helicases are directly coupled to transcriptional repression by protein sumoylation.
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Affiliation(s)
- Martin B Lee
- Department of Physiology, Biomedical Sciences Graduate Program, Graduate Program in Biological Sciences, Mission Bay Campus, University of California, San Francisco, Box 0444, San Francisco, CA 94143-2611, USA
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36
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Park SE, Xu J, Frolova A, Liao L, O'Malley BW, Katzenellenbogen BS. Genetic deletion of the repressor of estrogen receptor activity (REA) enhances the response to estrogen in target tissues in vivo. Mol Cell Biol 2005; 25:1989-99. [PMID: 15713652 PMCID: PMC549370 DOI: 10.1128/mcb.25.5.1989-1999.2005] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
We previously identified a coregulator, repressor of estrogen receptor activity (REA), that directly interacts with estrogen receptor (ER) and represses ER transcriptional activity. Decreasing the intracellular level of REA by using small interfering RNA knockdown or antisense RNA approaches in cells in culture resulted in a significant increase in the level of up-regulation of estrogen-stimulated genes. To elucidate the functional activities of REA in vivo, we have used targeted disruption to delete the REA gene in mice. The targeting vector eliminated, by homologous recombination, the REA exon sequences encoding amino acids 12 to 201, which are required for REA repressive activity and for interaction with ER. The viability of heterozygous animals was similar to that of the wild type, whereas homozygous animals did not develop, suggesting a crucial role for REA in early development. Female, but not male, heterozygous animals had an increased body weight relative to age-matched wild-type animals beginning after puberty. REA mRNA and protein levels in uteri of heterozygous animals were half that of the wild type, and studies with heterozygous animals revealed a greater uterine weight gain and epithelial hyperproliferation in response to estradiol (E2) and a substantially greater stimulation by E2 of a number of estrogen up-regulated genes in the uterus. Even more dramatic in REA heterozygous animals was the loss of down regulation by E2 of genes in the uterus that are normally repressed by estrogen in wild-type animals. Mouse embryo fibroblasts derived from heterozygous embryos also displayed a greater transcriptional response to E2. These studies demonstrate that REA is a significant modulator of estrogen responsiveness in vivo: it normally restrains estrogen actions, moderating ER stimulation and enhancing ER repression of E2-regulated genes.
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Affiliation(s)
- Seong-Eun Park
- University of Illinois, Department of Molecular and Integrative Physiology, 524 Burrill Hall, 407 South Goodwin Ave., Urbana, IL 61801-3704, USA
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37
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Nandan MO, Yoon HS, Zhao W, Ouko LA, Chanchevalap S, Yang VW. Krüppel-like factor 5 mediates the transforming activity of oncogenic H-Ras. Oncogene 2004; 23:3404-13. [PMID: 15077182 PMCID: PMC1351030 DOI: 10.1038/sj.onc.1207397] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Previous studies indicate that Krüppel-like factor 5 (KLF5), also known as intestinal-enriched Krüppel-like factor (IKLF), is a positive regulator of cell proliferation and gives rise to a transformed phenotype when overexpressed. Here we demonstrate that levels of KLF5 transcript and protein are significantly elevated in oncogenic H-Ras-transformed NIH3T3 cells. These cells display an accelerated rate of proliferation in both serum-containing and serum-deprived media and form anchorage-independent colonies in soft agar assays. H-Ras-transformed cells also contain elevated mitogen-activated protein kinase (MAPK) activity. When treated with inhibitors of MEK (MAPK kinase), H-Ras-transformed cells lose their growth advantage and no longer form colonies. Significantly, levels of KLF5 transcript and protein are substantially reduced in H-Ras-transformed cells treated with MEK inhibitors. Moreover, inhibition of KLF5 expression in H-Ras-transformed cells with KLF5-specific small interfering RNA (siRNA) leads to a decreased rate of proliferation and a significant reduction in colony formation. H-Ras-transformed cells also contain elevated levels of Egr1 that are diminished by MEK inhibitors. Inhibition of Egr1 by siRNA results in a reduced level of KLF5, indicating that Egr1 mediates the inductive action of MAPK on KLF5. Lastly, KLF5 activates expression of cyclin D1. These findings indicate that the increased expression of KLF5 in H-Ras-transformed cells is secondary to increased MAPK activity from H-Ras overexpression and that the elevated level of KLF5 is in part responsible for the proproliferative and transforming activities of oncogenic H-Ras.
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Affiliation(s)
- Mandayam O Nandan
- Department of Medicine, Division of Digestive Diseases, Emory University School of Medicine, Atlanta, GA, USA
| | - Hong S Yoon
- Department of Medicine, Division of Digestive Diseases, Emory University School of Medicine, Atlanta, GA, USA
| | - Weidong Zhao
- Department of Medicine, Division of Digestive Diseases, Emory University School of Medicine, Atlanta, GA, USA
| | - Lillian A Ouko
- Department of Medicine, Division of Digestive Diseases, Emory University School of Medicine, Atlanta, GA, USA
| | - Sengthong Chanchevalap
- Department of Medicine, Division of Digestive Diseases, Emory University School of Medicine, Atlanta, GA, USA
| | - Vincent W Yang
- Department of Medicine, Division of Digestive Diseases, Emory University School of Medicine, Atlanta, GA, USA
- Department of Hematology and Oncology, Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA, USA
- *Correspondence: VW Yang, Department of Medicine, Division of Digestive Diseases, Emory University School of Medicine, 201 Whitehead Research Building, 615 Michael Street, Atlanta, GA 30322, USA; E-mail:
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Heldring N, Nilsson M, Buehrer B, Treuter E, Gustafsson JA. Identification of tamoxifen-induced coregulator interaction surfaces within the ligand-binding domain of estrogen receptors. Mol Cell Biol 2004; 24:3445-59. [PMID: 15060164 PMCID: PMC381632 DOI: 10.1128/mcb.24.8.3445-3459.2004] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Tamoxifen is a selective estrogen receptor (ER) modulator that is clinically used as an antagonist to treat estrogen-dependent breast cancers but displays unwanted agonistic effects in other tissues. Previous studies on ERalpha have delineated a role of the N-terminal activation function AF-1 in mediating the agonistic effects of tamoxifen, while the mechanisms for how ERbeta mediates tamoxifen action remain to be elucidated. As peptides can be used to detect distinct receptor conformations and binding surfaces for coactivators and corepressors, we attempted in this study to identify previously unrecognized peptides that interact specifically with ERs in the presence of tamoxifen. We identified two distinct peptides among others that are highly selective for tamoxifen-bound ERalpha or ERbeta. Domain mapping and mutation analysis suggest that these peptides recognize a novel tamoxifen-induced binding surface within the C-terminal ligand-binding domain that is distinct from the agonist-induced AF-2 surface. Peptide expression specifically inhibited transcriptional ER activity in response to tamoxifen, presumably by preventing the binding of endogenous coactivators. Moreover, tamoxifen-responsive and ER subtype-selective coactivators were engineered by replacing the LXXLL motifs in the coactivator TIF2 with either of the two peptides. Finally, our results indicate that related coactivators may act via the novel tamoxifen-induced binding surface, referred to as AF-T, allowing us to propose a revised model of tamoxifen agonism.
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Affiliation(s)
- Nina Heldring
- Department of Biosciences at Novum, Karolinska Institutet, S-14157 Huddinge, Sweden
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39
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Rocak S, Linder P. DEAD-box proteins: the driving forces behind RNA metabolism. Nat Rev Mol Cell Biol 2004; 5:232-41. [PMID: 14991003 DOI: 10.1038/nrm1335] [Citation(s) in RCA: 582] [Impact Index Per Article: 29.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Sanda Rocak
- Departement de Biochimie Médicale, Centre Médical Universitaire, 1 rue Michel Servet, CH-1211 Geneva 4, Switzerland
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40
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Tsai-Morris CH, Lei S, Jiang Q, Sheng Y, Dufau ML. Genomic organization and transcriptional analysis of gonadotropin-regulated testicular RNA helicase—GRTH/DDX25 gene. Gene 2004; 331:83-94. [PMID: 15094194 DOI: 10.1016/j.gene.2004.02.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2003] [Revised: 01/07/2004] [Accepted: 02/04/2004] [Indexed: 10/26/2022]
Abstract
The gonadotropin-regulated testicular RNA helicase (GRTH/DDX25) is a new member of the DEAD-box protein family. Phylogenetic analysis revealed that GRTH is distantly related to other members of the family. GRTH is transcriptionally up-regulated by gonadotropin, displays ATPase and RNA helicase activities, and participates in germ cell development. To understand the regulation of GRTH gene expression, we investigated its structural organization and aspects of basal transcriptional regulation at the promoter domain. The 20-kb mouse GRTH gene contains 12 coding exons and all but one of its conserved helicase motifs are contained within single exons. GRTH is a TATA-less gene with multiple transcriptional start sites (TSS), GC-rich sequences and a promoter located within -205/+63 bp of the gene. Sequences -852/-354 and -501/-354 bp caused 40-60% and >80% inhibition of transcription in expressing and non-expressing cells, respectively. Transcriptional activity was recovered only in expressing cells by the addition of upstream sequences (-1085/-852 bp). Sp1/Sp3 supported basal transcriptional activity in all cell types, while E-box was an activator-binding site only in non-expressing cells. These findings indicate that a differential pattern of transcriptional regulation may be involved in the control of GRTH gene expression in a cell-specific manner.
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Affiliation(s)
- Chon-Hwa Tsai-Morris
- Section on Molecular Endocrinology, ERRB, National Institute of Child Health and Human Development, National Institutes of Health, Building 49-6A36, 49 Convent Dr., Bethesda, MD 20892-4510, USA.
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41
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Gillian AL, Svaren J. The Ddx20/DP103 Dead Box Protein Represses Transcriptional Activation by Egr2/Krox-20. J Biol Chem 2004; 279:9056-63. [PMID: 14699164 DOI: 10.1074/jbc.m309308200] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The early growth response 2 (Egr2/Krox-20) transcription factor is essential for myelination of the peripheral nervous system and segmentation of the vertebrate hindbrain. To probe the mechanism by which Egr2 is regulated, we used a yeast two-hybrid assay and identified an RNA helicase, Ddx20 (DP103/Gemin3), as an Egr2-interacting protein. Mammalian two-hybrid assays indicated that Ddx20 can interact with Egr1, Egr3, and Egr4, in addition to Egr2, making it the only known cofactor that interacts with all four Egr family members. Using several Egr2 target promoters, we found that Ddx20 repressed Egr2-mediated transcriptional activation with significant promoter specificity. In addition, Ddx20 repressed Egr2-mediated activation of the endogenous insulin-like growth factor 2 (IGF2) gene. Interestingly, the C-terminal segment of Ddx20, which lacks the DEAD box helicase domain, was sufficient for its robust and specific repression. We also examined possible interactions between Ddx20 and Nab proteins, the only other known corepressors of the Egr family, and found that these two corepressors act independently. Finally, transcriptional repression assays performed in the presence of a histone deacetylase inhibitor (trichostatin A) indicate that although repression of certain promoters by Ddx20 requires histone deacetylase activity, another repression mechanism must also be involved. Because Egr2 is critical for hindbrain development and peripheral nerve myelination, modulation of Egr2 by Ddx20 may play an important role in maintaining the correct expression level of Egr2 target genes.
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Affiliation(s)
- Anne Lynn Gillian
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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Smith CL, O'Malley BW. Coregulator function: a key to understanding tissue specificity of selective receptor modulators. Endocr Rev 2004; 25:45-71. [PMID: 14769827 DOI: 10.1210/er.2003-0023] [Citation(s) in RCA: 640] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Ligands for the nuclear receptor superfamily control many aspects of biology, including development, reproduction, and homeostasis, through regulation of the transcriptional activity of their cognate receptors. Selective receptor modulators (SRMs) are receptor ligands that exhibit agonistic or antagonistic biocharacter in a cell- and tissue context-dependent manner. The prototypical SRM is tamoxifen, which as a selective estrogen receptor modulator, can activate or inhibit estrogen receptor action. SRM-induced alterations in the conformation of the ligand-binding domains of nuclear receptors influence their abilities to interact with other proteins, such as coactivators and corepressors. It has been postulated, therefore, that the relative balance of coactivator and corepressor expression within a given target cell determines the relative agonist vs. antagonist activity of SRMs. However, recent evidence reveals that the cellular environment also plays a critical role in determining SRM biocharacter. Cellular signaling influences the activity and subcellular localization of coactivators and corepressors as well as nuclear receptors, and this contributes to gene-, cell-, and tissue-specific responses to SRM ligands. Increased understanding of the effect of cellular environment on nuclear receptors and their coregulators has the potential to open the field of SRM discovery and research to many members of the nuclear receptor superfamily.
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Affiliation(s)
- Carolyn L Smith
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030, USA.
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43
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Abstract
Estrogens work along with genetic changes to promote the development and growth of breast cancers. Because estrogenic hormones act via the estrogen receptors (ERs), ER-alpha and ER-beta, and the ER is present in more than half of breast tumors, this receptor has been the most widely targeted protein in breast cancer therapy. The presence of the ER in breast tumors predicts improved disease-free survival and response to selective ER modulators (SERMs), such as tamoxifen, or other forms of endocrine therapy. Suppression of ER activity by SERMs has proven to be a great benefit in the treatment of breast cancers and also in the prevention of breast cancer in women at high risk for the disease. The Study of Tamoxifen and Raloxifene trial comparing tamoxifen versus raloxifene effectiveness in breast cancer prevention is currently under way. To understand the balance of beneficial and undesirable effects of SERMs and to optimize their effectiveness, current investigations seek to characterize the genes activated or suppressed by these agents. Elucidation of the gene networks and cell signaling pathways under estrogen and SERM regulation and a clearer definition of the respective roles of ER-alpha and ER-beta and their coregulators in the actions of selective ER ligands, should enable the identification of new gene targets for therapeutic intervention and the development of novel drugs for the optimal treatment and prevention of breast cancer.
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Affiliation(s)
- Benita S Katzenellenbogen
- Department of Molecular and Integrative Physiology, University of Illinois and College of Medicine, Urbana, IL, USA
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44
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White JH, Fernandes I, Mader S, Yang XJ. Corepressor Recruitment by Agonist-Bound Nuclear Receptors. NUCLEAR RECEPTOR COREGULATORS 2004; 68:123-43. [PMID: 15193453 DOI: 10.1016/s0083-6729(04)68004-6] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Members of the nuclear receptor superfamily are ligand-regulated transcription factors that are composed of a series of conserved domains. These receptors are targets of a wide range of lipophilic signaling molecules that modulate many aspects of physiology and metabolism. Binding of cognate ligands to receptors induces a conformational change in the ligand binding domain (LBD) that creates a pocket for recruitment of coregulatory proteins, which are essential for ligand-dependent regulation of transcription. Several coregulatory proteins that interact with hormone-bound receptors contain characteristic helical LXXLL motifs, known as nuclear receptor (NR) boxes. Generally, ligand binding to receptors is associated with activation of transcription, and most of the NR box-containing proteins characterized to date are coactivators. However, a full understanding of the function of hormone-bound receptors must also incorporate their recruitment of corepressors. The recent identification of ligand-dependent corepressor (LCoR) is a case in point. LCoR contains a single NR box that mediates its hormone-dependent interaction with several nuclear receptors. It functions as a molecular scaffold that recruits several proteins that function in transcriptional repression. Remarkably, although the two proteins share only very limited homology, LCoR and another NR box-containing corepressor RIP140 recruit similar cofactors implicated in transcriptional repression, suggesting many parallels in their mechanisms of action. Corepressors such as LCoR and RIP140 may function in negative feedback loops to attenuate hormone-induced transactivation, act more transiently as part of a cycle of cofactors recruited to target promoters by ligand-bound receptors, or function in hormone-induced target gene repression.
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Affiliation(s)
- John H White
- Department of Physiology, McGill University, McIntyre Medical Sciences Bldg, Montreal, Quebec H3G 1Y6, Canada
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White KA, Yore MM, Warburton SL, Vaseva AV, Rieder E, Freemantle SJ, Spinella MJ. Negative Feedback at the Level of Nuclear Receptor Coregulation. J Biol Chem 2003; 278:43889-92. [PMID: 14506269 DOI: 10.1074/jbc.c300374200] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Nuclear receptor-mediated gene expression is proposed to be regulated by the ordered recruitment of large protein complexes in which activity depends on mutual interactions and posttranslational modifications. In contrast, relatively little attention has been given to mechanisms regulating the expression of the coregulator proteins themselves. Previously we have shown that the ligand-dependent corepressor, RIP140, is a direct transcriptional target of all-trans retinoic acid (RA). Here we demonstrate that RA induction of RIP140 constitutes a rate-limiting step in the regulation of retinoic acid receptor signaling. Silencing of the RA induction of RIP140 dramatically enhances and accelerates retinoid receptor transactivation, endogenous expression of other RA target genes, and RA-induced neuronal differentiation and cell cycle arrest in human embryonal carcinoma cells. The data suggest that RA induction of RIP140 constitutes a functional negative feedback loop that limits activation of retinoid receptors in the continued presence of RA and that acutely regulated expression of coregulators may be a general regulatory mechanism in hormonal signaling.
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Affiliation(s)
- Kristina A White
- Department of Pharmacology and Toxicology, Dartmouth Medical School, Dartmouth Hitchcock Medical Center, Hanover, New Hampshire 03755, USA
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Oesterreich S. Scaffold attachment factors SAFB1 and SAFB2: Innocent bystanders or critical players in breast tumorigenesis? J Cell Biochem 2003; 90:653-61. [PMID: 14587024 DOI: 10.1002/jcb.10685] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Scaffold attachment factor B1 (SAFB1) and SAFB2 are large, multifunctional proteins that have been implicated in numerous cellular processes including chromatin organization, transcriptional regulation, RNA splicing, and stress response. While the two homologous proteins show high similarity, and functional domains are highly conserved, evidence suggests that they also have unique properties. For example, SAFB2 can be found in both the nucleus and cytoplasm, whereas SAFB1 seems to be mainly localized in the nucleus. In breast cancer cells, SAFBs function as estrogen receptor corepressors and growth inhibitors. SAFB protein expression is lost in approximately 20% of breast cancers. Interestingly, the two genes reside in close proximity, oriented head-to-head, on chromosome 19p13, a locus which is frequently lost in clinical breast cancer specimens. Furthermore, SAFB1 mutations have been identified in breast tumors that were not present in adjacent normal tissue. The possibility that SAFB1 and SAFB2 are novel breast tumor suppressor genes, and how they might function in this role, are discussed.
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Affiliation(s)
- Steffi Oesterreich
- Department of Medicine and Molecular and Cellular Biology, The Breast Center, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA.
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Lin VY, Resnick EM, Shupnik MA. Truncated estrogen receptor product-1 stimulates estrogen receptor alpha transcriptional activity by titration of repressor proteins. J Biol Chem 2003; 278:38125-31. [PMID: 12878603 DOI: 10.1074/jbc.m303882200] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The truncated estrogen receptor product-1 (TERP-1, or TERP) is a pituitary-specific isoform of estrogen receptor alpha (ERalpha), and its expression is regulated by estrogen. TERP modulates the transcriptional activity of ERalpha but has no independent effect on transcription of estrogen-response element-containing promoters. At low concentrations, TERP stimulates ERalpha transcriptional activity in transient transfection assays. At TERP concentrations equal to or greater than full-length ERalpha, TERP forms dimers with ERalpha and reduces both ligand-dependent and -independent transcription. A dimerization mutant of TERP, TERP L509R, stimulated ERalpha transcription at all concentrations. We hypothesized that TERP stimulates ERalpha transcriptional activity by titrating suppressors of ERalpha activity. We found that repressor of estrogen receptor activity (REA), originally isolated from human breast cancer cells, is present in mouse pituitary gonadotrope cell lines. Levels of REA vary slightly throughout the rat reproductive cycle, but TERP mRNA and protein vary much more dramatically. In transfection experiments, REA suppressed ERalpha transcriptional activity, and TERP L509R was able to alleviate transcriptional suppression by REA. In glutathione S-transferase pull-down assays, TERP bound to REA more efficiently than did ERalpha at equivalent concentrations, suggesting that REA will preferentially bind to TERP. Our findings suggest that the stimulation of pituitary ERalpha activity by low concentrations of TERP can occur by titration of corepressors such as REA.
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Affiliation(s)
- Vicky Y Lin
- Department of Pharmacology, Division of Endocrinology and Metabolism, University of Virginia, Charlottesville, Virginia 22908, USA
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48
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Abstract
RNA duplexes of 21 - 23 nucleotides (nts), with approximately 2 nt 3' overhangs (called small interfering RNAs or siRNAs), have recently been shown to mediate sequence-specific inhibition of gene expression in mammalian cells via a post-transcriptional gene silencing (PTGS) mechanism termed RNA interference (RNAi). RNAi has been rapidly adopted as a functional genomics tool in a wide range of species, has been adapted to allow for the transient or stable knockdown of gene expression generation in cell lines and animals, and has been developed for high-throughput analysis of gene function in Caenorhabditis elegans. With an increasing list of genes successfully knocked-down by RNAi in mammalian cells and improvements in the delivery of siRNAs to cells, including in vivo delivery to mice, attention is now turning to assessing the potential RNAi has as a gene therapy approach. RNAi is likely to have the greatest impact as a therapeutic tool in two key clinical areas, cancer and infectious disease, but it also has the potential as a therapy for other disorders including some dominant genetic diseases. This review will describe the status of the science behind this novel mechanism and will illustrate the therapeutic potential of RNAi-based technologies, using examples from these critical clinical research areas.
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Affiliation(s)
- Natasha J Caplen
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, 10 Center Drive, 10C103, Bethesda, MD 20892, USA.
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