1
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Mfarej MG, Hyland CA, Sanchez AC, Falk MM, Iovine MK, Skibbens RV. Cohesin: an emerging master regulator at the heart of cardiac development. Mol Biol Cell 2023; 34:rs2. [PMID: 36947206 PMCID: PMC10162415 DOI: 10.1091/mbc.e22-12-0557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 03/10/2023] [Accepted: 03/17/2023] [Indexed: 03/23/2023] Open
Abstract
Cohesins are ATPase complexes that play central roles in cellular processes such as chromosome division, DNA repair, and gene expression. Cohesinopathies arise from mutations in cohesin proteins or cohesin complex regulators and encompass a family of related developmental disorders that present with a range of severe birth defects, affect many different physiological systems, and often lead to embryonic fatality. Treatments for cohesinopathies are limited, in large part due to the lack of understanding of cohesin biology. Thus, characterizing the signaling networks that lie upstream and downstream of cohesin-dependent pathways remains clinically relevant. Here, we highlight alterations in cohesins and cohesin regulators that result in cohesinopathies, with a focus on cardiac defects. In addition, we suggest a novel and more unifying view regarding the mechanisms through which cohesinopathy-based heart defects may arise.
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Affiliation(s)
- Michael G. Mfarej
- Department of Biological Sciences, Lehigh University, Bethlehem, PA 18015
| | - Caitlin A. Hyland
- Department of Biological Sciences, Lehigh University, Bethlehem, PA 18015
| | - Annie C. Sanchez
- Department of Biological Sciences, Lehigh University, Bethlehem, PA 18015
| | - Matthias M. Falk
- Department of Biological Sciences, Lehigh University, Bethlehem, PA 18015
| | - M. Kathryn Iovine
- Department of Biological Sciences, Lehigh University, Bethlehem, PA 18015
| | - Robert V. Skibbens
- Department of Biological Sciences, Lehigh University, Bethlehem, PA 18015
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2
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Varshney A, Chahal G, Santos L, Stolper J, Hallab JC, Nim HT, Nikolov M, Yip A, Ramialison M. Human Cardiac Transcription Factor Networks. SYSTEMS MEDICINE 2021. [DOI: 10.1016/b978-0-12-801238-3.11597-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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3
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Conjugated activation of myocardial-specific transcription of Gja5 by a pair of Nkx2-5-Shox2 co-responsive elements. Dev Biol 2020; 465:79-87. [PMID: 32687896 DOI: 10.1016/j.ydbio.2020.07.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 07/06/2020] [Accepted: 07/07/2020] [Indexed: 02/08/2023]
Abstract
The sinoatrial node (SAN) is the primary pacemaker in the heart. During cardiogenesis, Shox2 and Nkx2-5 are co-expressed in the junction domain of the SAN and regulate pacemaker cell fate through a Shox2-Nkx2-5 antagonism. Cx40 is a marker of working myocardium and an Nkx2-5 transcriptional output antagonized by Shox2, but the underlying regulatory mechanisms remain elusive. Here we characterized a bona fide myocardial-specific Gja5 (coding gene of Cx40) distal enhancer consisting of a pair of Nkx2-5 and Shox2 co-bound elements in the regulatory region of Gja5. Transgenic reporter assays revealed that neither element alone, but the conjugation of both elements together, drives myocardial-specific transcription. Genetic analyses confirmed that the activation of this enhancer depends on Nkx2-5 but is inhibited by Shox2 in vivo, and its presence is essential for Gja5 expression in the myocardium but not the endothelial cells of the heart. Furthermore, chromatin conformation analysis showed an Nkx2-5-dependent loop formation between these two elements and the Gja5 promoter in vivo, indicating that Nkx2-5 bridges the conjugated activation of this enhancer by pairing the two elements to the Gja5 promoter.
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4
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Abstract
Various strategies have been applied to replace the loss of cardiomyocytes in order to restore reduced cardiac function and prevent the progression of heart disease. Intensive research efforts in the field of cellular reprogramming and cell transplantation may eventually lead to efficient in vivo applications for the treatment of cardiac injuries, representing a novel treatment strategy for regenerative medicine. Modulation of cardiac transcription factor (TF) networks by chemical entities represents another viable option for therapeutic interventions. Comprehensive screening projects have revealed a number of molecular entities acting on molecular pathways highly critical for cellular lineage commitment and differentiation, including compounds targeting Wnt- and transforming growth factor beta (TGFβ)-signaling. Furthermore, previous studies have demonstrated that GATA4 and NKX2-5 are essential TFs in gene regulation of cardiac development and hypertrophy. For example, both of these TFs are required to fully activate mechanical stretch-responsive genes such as atrial natriuretic peptide and brain natriuretic peptide (BNP). We have previously reported that the compound 3i-1000 efficiently inhibited the synergy of the GATA4-NKX2-5 interaction. Cellular effects of 3i-1000 have been further characterized in a number of confirmatory in vitro bioassays, including rat cardiac myocytes and animal models of ischemic injury and angiotensin II-induced pressure overload, suggesting the potential for small molecule-induced cardioprotection.
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Affiliation(s)
- Mika J. Välimäki
- Drug Research Program, Division of Pharmacology and Pharmacotherapy, Faculty of PharmacyUniversity of HelsinkiHelsinki, Finland
| | - Heikki J. Ruskoaho
- Drug Research Program, Division of Pharmacology and Pharmacotherapy, Faculty of PharmacyUniversity of HelsinkiHelsinki, Finland
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5
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Kerkhofs C, Stevens SJC, Faust SN, Rae W, Williams AP, Wurm P, Østern R, Fockens P, Würfel C, Laass M, Kokke F, Stegmann APA, Brunner HG. Mutations in RPSA and NKX2-3 link development of the spleen and intestinal vasculature. Hum Mutat 2019; 41:196-202. [PMID: 31498527 PMCID: PMC6972609 DOI: 10.1002/humu.23909] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 08/28/2019] [Accepted: 09/02/2019] [Indexed: 12/11/2022]
Abstract
Idiopathic intestinal varicosis is a developmental disorder defined by dilated and convoluted submucosal veins in the colon or small bowel. A limited number of families with idiopathic intestinal varices has been reported, but the genetic cause has not yet been identified. We performed whole‐exome and targeted Sanger sequencing of candidate genes in five intestinal varicosis families. In four families, mutations in the RPSA gene were found, a gene previously linked to congenital asplenia. Individuals in these pedigrees had intestinal varicose veins and angiodysplasia, often in combination with asplenia. In a further four‐generation pedigree that only showed intestinal varicosities, the RPSA gene was normal. Instead, a nonsense mutation in the homeobox gene NKX2‐3 was detected which cosegregated with the disease in this large family with a LOD (logarithm of the odds) score of 3.3. NKX2‐3 is a component of a molecular pathway underlying spleen and gut vasculature development in mice. Our results provide a molecular basis for familial idiopathic intestinal varices. We provide evidence for a relationship between the molecular pathways underlying the development of the spleen and intestinal mucosal vasculature that is conserved between humans and mice. We propose that clinical management of intestinal varices, should include assessment of a functional spleen.
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Affiliation(s)
- Chantal Kerkhofs
- Department of Clinical Genetics and GROW-School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Servi J C Stevens
- Department of Clinical Genetics and GROW-School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Saul N Faust
- NIHR Southampton Clinical Research Facility and NIHR Southampton Biomedical Research Centre, University of Southampton Faculty of Medicine and University Hospital Southampton, NHS Foundation Trust, Southampton, UK.,Departments of Immunology and Paediatric Immunology and Infectious Diseases, University Hospital Southampton, UK
| | - William Rae
- NIHR Southampton Clinical Research Facility and NIHR Southampton Biomedical Research Centre, University of Southampton Faculty of Medicine and University Hospital Southampton, NHS Foundation Trust, Southampton, UK.,Departments of Immunology and Paediatric Immunology and Infectious Diseases, University Hospital Southampton, UK
| | - Anthony P Williams
- NIHR Southampton Clinical Research Facility and NIHR Southampton Biomedical Research Centre, University of Southampton Faculty of Medicine and University Hospital Southampton, NHS Foundation Trust, Southampton, UK.,Departments of Immunology and Paediatric Immunology and Infectious Diseases, University Hospital Southampton, UK
| | - Peter Wurm
- Department of Gastroenterology, University Hospitals of Leicester, NHS Trust, Leicester, UK
| | - Rune Østern
- Department of Pathology and Medical Genetics, St. Olavs Hospital, Trondheim, Norway
| | - Paul Fockens
- Department of Gastrointestinal diseases, Academic Medical Center, Amsterdam, The Netherlands
| | - Christiane Würfel
- Department of Pediatrics, University Hospital Dresden, Dresden, Germany
| | - Martin Laass
- Department of Pediatrics, University Hospital Dresden, Dresden, Germany
| | - Freddy Kokke
- Department of Pediatric Gastroenterology, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Alexander P A Stegmann
- Department of Clinical Genetics and GROW-School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Han G Brunner
- Department of Clinical Genetics and GROW-School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht, The Netherlands.,Department of Human Genetics, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
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6
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Horton AJ, Brooker J, Streitfeld WS, Flessa ME, Pillai B, Simpson R, Clark CD, Gooz MB, Sutton KK, Foley AC, Lee KH. Nkx2-5 Second Heart Field Target Gene Ccdc117 Regulates DNA Metabolism and Proliferation. Sci Rep 2019; 9:1738. [PMID: 30742009 PMCID: PMC6370788 DOI: 10.1038/s41598-019-39078-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 11/13/2018] [Indexed: 11/08/2022] Open
Abstract
The cardiac transcription factor Nkx2-5 is essential for normal outflow tract (OFT) and right ventricle (RV) development. Nkx2-5-/- null mouse embryos display severe OFT and RV hypoplasia and a single ventricle phenotype due to decreased proliferation of Second Heart Field (SHF) cells, a pool of cardiac progenitors present in anterior pharyngeal arch mesoderm at mid-gestation. However, definition of the precise role of Nkx2-5 in facilitating SHF expansion is incomplete. We have found that Nkx2-5 positively and directly regulates a novel target gene, Ccdc117, in cells of the SHF at these stages. The nuclear/mitotic spindle associated protein Ccdc117 interacts with the MIP18/MMS19 cytoplasmic iron-sulfur (FeS) cluster assembly (CIA) complex, which transfers critical FeS clusters to several key enzymes with functions in DNA repair and replication. Loss of cellular Ccdc117 expression results in reduced proliferation rates associated with a delay at the G1-S transition, decreased rates of DNA synthesis, and unresolved DNA damage. These results implicate a novel role for Nkx2-5 in the regulation of cell cycle events in the developing heart, through Ccdc117's interaction with elements of the CIA pathway and the facilitation of DNA replication during SHF expansion.
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Affiliation(s)
- Anthony J Horton
- Departments of Pediatrics and Obstetrics and Gynecology, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - John Brooker
- Departments of Pediatrics and Obstetrics and Gynecology, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - William S Streitfeld
- Departments of Pediatrics and Obstetrics and Gynecology, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Meaghan E Flessa
- Departments of Pediatrics and Obstetrics and Gynecology, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Balakrishnan Pillai
- Departments of Pediatrics and Obstetrics and Gynecology, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Raychel Simpson
- Departments of Pediatrics and Obstetrics and Gynecology, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Christopher D Clark
- Departments of Pediatrics and Obstetrics and Gynecology, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Monika B Gooz
- Department of Pharmaceutical and Biomedical Sciences, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Kimberly K Sutton
- Departments of Pediatrics and Obstetrics and Gynecology, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Ann C Foley
- Regenerative Medicine and Cell Biology Department, Medical University of South Carolina, Charleston, SC, 29425, USA
- Bioengineering Department, Clemson University - MUSC, Charleston, SC, 29425, USA
| | - Kyu-Ho Lee
- Departments of Pediatrics and Obstetrics and Gynecology, Medical University of South Carolina, Charleston, SC, 29425, USA.
- Regenerative Medicine and Cell Biology Department, Medical University of South Carolina, Charleston, SC, 29425, USA.
- Bioengineering Department, Clemson University - MUSC, Charleston, SC, 29425, USA.
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7
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NKX2.5 is expressed in papillary thyroid carcinomas and regulates differentiation in thyroid cells. BMC Cancer 2018; 18:498. [PMID: 29716526 PMCID: PMC5930850 DOI: 10.1186/s12885-018-4399-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 04/18/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND NKX2.5 is a transcription factor transiently expressed during thyroid organogenesis. Recently, several works have pointed out the oncogenic role of NKX2.5 in a variety of tumors. We therefore hypothesized that NKX2.5 could also play a role in thyroid cancer. METHODS The validation of NKX2.5 expression was assessed by immunohistochemistry analysis in a Brazilian case series of 10 papillary thyroid carcinoma (PTC) patients. Then, the long-term prognostic value of NKX2.5 and its correlation with clinicopathologic features of 51 PTC patients was evaluated in a cohort with 10-years follow-up (1990-1999). Besides, the effect of NKX2.5 overexpression on thyroid differentiation markers and function was also investigated in a non-tumor thyroid cell line (PCCL3). RESULTS NKX2.5 was shown to be expressed in most PTC samples (8/10, case series; 27/51, cohort). Patients who had tumors expressing NKX2.5 showed lower rates of persistence/recurrence (p = 0.013). Overexpression of NKX2.5 in PCCL3 cells led to: 1) downregulation of thyroid differentiation markers (thyrotropin receptor, thyroperoxidase and sodium-iodide symporter); 2) reduced iodide uptake; 3) increased extracellular H2O2 generation, dual oxidase 1 mRNA levels and activity of DuOx1 promoter. CONCLUSIONS In summary, NKX2.5 is expressed in most PTC samples analyzed and its presence correlates to better prognosis of PTC. In vitro, NKX2.5 overexpression reduces the expression of thyroid differentiation markers and increases ROS production. Thus, our data suggests that NKX2.5 could play a role in thyroid carcinogenesis.
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8
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Furtado MB, Wilmanns JC, Chandran A, Perera J, Hon O, Biben C, Willow TJ, Nim HT, Kaur G, Simonds S, Wu Q, Willians D, Salimova E, Plachta N, Denegre JM, Murray SA, Fatkin D, Cowley M, Pearson JT, Kaye D, Ramialison M, Harvey RP, Rosenthal NA, Costa MW. Point mutations in murine Nkx2-5 phenocopy human congenital heart disease and induce pathogenic Wnt signaling. JCI Insight 2017; 2:e88271. [PMID: 28352650 DOI: 10.1172/jci.insight.88271] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Mutations in the Nkx2-5 gene are a main cause of congenital heart disease. Several studies have addressed the phenotypic consequences of disrupting the Nkx2-5 gene locus, although animal models to date failed to recapitulate the full spectrum of the human disease. Here, we describe a new Nkx2-5 point mutation murine model, akin to its human counterpart disease-generating mutation. Our model fully reproduces the morphological and physiological clinical presentations of the disease and reveals an understudied aspect of Nkx2-5-driven pathology, a primary right ventricular dysfunction. We further describe the molecular consequences of disrupting the transcriptional network regulated by Nkx2-5 in the heart and show that Nkx2-5-dependent perturbation of the Wnt signaling pathway promotes heart dysfunction through alteration of cardiomyocyte metabolism. Our data provide mechanistic insights on how Nkx2-5 regulates heart function and metabolism, a link in the study of congenital heart disease, and confirms that our models are the first murine genetic models to our knowledge to present all spectra of clinically relevant adult congenital heart disease phenotypes generated by NKX2-5 mutations in patients.
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Affiliation(s)
- Milena B Furtado
- The Jackson Laboratory, Bar Harbor, Maine, USA.,Australian Regenerative Medicine Institute, Monash University, Clayton, Australia
| | - Julia C Wilmanns
- Australian Regenerative Medicine Institute, Monash University, Clayton, Australia.,Department of Cardiology and Angiology, Medical School Hannover, Hannover, Germany
| | - Anjana Chandran
- Australian Regenerative Medicine Institute, Monash University, Clayton, Australia
| | - Joelle Perera
- Australian Regenerative Medicine Institute, Monash University, Clayton, Australia
| | - Olivia Hon
- The Jackson Laboratory, Bar Harbor, Maine, USA
| | - Christine Biben
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
| | | | - Hieu T Nim
- Australian Regenerative Medicine Institute, Monash University, Clayton, Australia
| | - Gurpreet Kaur
- Australian Regenerative Medicine Institute, Monash University, Clayton, Australia
| | | | - Qizhu Wu
- Monash Biomedical Imaging, Monash University, Clayton, Australia
| | - David Willians
- Heart Failure Research Group, Baker IDI Heart and Diabetes Institute, Melbourne, Australia
| | - Ekaterina Salimova
- Australian Regenerative Medicine Institute, Monash University, Clayton, Australia
| | | | | | | | - Diane Fatkin
- Molecular Cardiology, Victor Chang Cardiac Research Institute, Darlinghurst, Australia.,Faculty of Medicine and School of Biological and Biomolecular Sciences, University of New South Wales, Kensington, Australia.,Cardiology Department, St. Vincent's Hospital, Darlinghurst, Australia
| | | | - James T Pearson
- Department of Physiology.,Monash Biomedical Imaging, Monash University, Clayton, Australia
| | - David Kaye
- Heart Failure Research Group, Baker IDI Heart and Diabetes Institute, Melbourne, Australia
| | - Mirana Ramialison
- Australian Regenerative Medicine Institute, Monash University, Clayton, Australia
| | - Richard P Harvey
- Faculty of Medicine and School of Biological and Biomolecular Sciences, University of New South Wales, Kensington, Australia.,Stem Cell Biology Division, Victor Chang Cardiac Research Institute, Darlinghurst, Australia
| | - Nadia A Rosenthal
- The Jackson Laboratory, Bar Harbor, Maine, USA.,Australian Regenerative Medicine Institute, Monash University, Clayton, Australia.,National Heart and Lung Institute, Imperial College, London, United Kingdom
| | - Mauro W Costa
- The Jackson Laboratory, Bar Harbor, Maine, USA.,Australian Regenerative Medicine Institute, Monash University, Clayton, Australia
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9
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Pradhan L, Gopal S, Li S, Ashur S, Suryanarayanan S, Kasahara H, Nam HJ. Intermolecular Interactions of Cardiac Transcription Factors NKX2.5 and TBX5. Biochemistry 2016; 55:1702-10. [DOI: 10.1021/acs.biochem.6b00171] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Lagnajeet Pradhan
- Department
of Bioengineering, University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Sunil Gopal
- Department
of Bioengineering, University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Shichang Li
- Department
of Bioengineering, University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Shayan Ashur
- Department
of Bioengineering, University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Saai Suryanarayanan
- Department
of Bioengineering, University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Hideko Kasahara
- Department of Functional Genomics, University of Florida, Gainesville, Florida 32610, United States
| | - Hyun-Joo Nam
- Department
of Bioengineering, University of Texas at Dallas, Richardson, Texas 75080, United States
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10
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Kinnunen S, Välimäki M, Tölli M, Wohlfahrt G, Darwich R, Komati H, Nemer M, Ruskoaho H. Nuclear Receptor-Like Structure and Interaction of Congenital Heart Disease-Associated Factors GATA4 and NKX2-5. PLoS One 2015; 10:e0144145. [PMID: 26642209 PMCID: PMC4671672 DOI: 10.1371/journal.pone.0144145] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 11/13/2015] [Indexed: 01/24/2023] Open
Abstract
AIMS Transcription factor GATA4 is a dosage sensitive regulator of heart development and alterations in its level or activity lead to congenital heart disease (CHD). GATA4 has also been implicated in cardiac regeneration and repair. GATA4 action involves combinatorial interaction with other cofactors such as NKX2-5, another critical cardiac regulator whose mutations also cause CHD. Despite its critical importance to the heart and its evolutionary conservation across species, the structural basis of the GATA4-NKX2-5 interaction remains incompletely understood. METHODS AND RESULTS A homology model was constructed and used to identify surface amino acids important for the interaction of GATA4 and NKX2-5. These residues were subjected to site-directed mutagenesis, and the mutant proteins were characterized for their ability to bind DNA and to physically and functionally interact with NKX2-5. The studies identify 5 highly conserved amino acids in the second zinc finger (N272, R283, Q274, K299) and its C-terminal extension (R319) that are critical for physical and functional interaction with the third alpha helix of NKX2-5 homeodomain. Integration of the experimental data with computational modeling suggests that the structural arrangement of the zinc finger-homeodomain resembles the architecture of the conserved DNA binding domain of nuclear receptors. CONCLUSIONS The results provide novel insight into the structural basis for protein-protein interactions between two important classes of transcription factors. The model proposed will help to elucidate the molecular basis for disease causing mutations in GATA4 and NKX2-5 and may be relevant to other members of the GATA and NK classes of transcription factors.
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Affiliation(s)
- Sini Kinnunen
- Division of Pharmacology and Pharmacotherapy, University of Helsinki, Helsinki, Finland
- Institute of Biomedicine, Department of Pharmacology and Toxicology, University of Oulu, Oulu, Finland
| | - Mika Välimäki
- Division of Pharmacology and Pharmacotherapy, University of Helsinki, Helsinki, Finland
- Institute of Biomedicine, Department of Pharmacology and Toxicology, University of Oulu, Oulu, Finland
| | - Marja Tölli
- Institute of Biomedicine, Department of Pharmacology and Toxicology, University of Oulu, Oulu, Finland
| | - Gerd Wohlfahrt
- Orion Pharma, Computer-Aided Drug Design, Espoo, Finland
| | - Rami Darwich
- Laboratory of Cardiac Development and Differentiation, Department of Biochemistry, Immunology and Microbiology, University of Ottawa, Ottawa, Canada
| | - Hiba Komati
- Laboratory of Cardiac Development and Differentiation, Department of Biochemistry, Immunology and Microbiology, University of Ottawa, Ottawa, Canada
| | - Mona Nemer
- Laboratory of Cardiac Development and Differentiation, Department of Biochemistry, Immunology and Microbiology, University of Ottawa, Ottawa, Canada
- * E-mail: (HR); (MN)
| | - Heikki Ruskoaho
- Division of Pharmacology and Pharmacotherapy, University of Helsinki, Helsinki, Finland
- Institute of Biomedicine, Department of Pharmacology and Toxicology, University of Oulu, Oulu, Finland
- * E-mail: (HR); (MN)
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11
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Cardiac transcription factor Nkx2.5 interacts with p53 and modulates its activity. Arch Biochem Biophys 2015; 569:45-53. [DOI: 10.1016/j.abb.2015.02.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 02/01/2015] [Indexed: 01/30/2023]
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12
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Cardoso-Weide L, Cardoso-Penha R, Costa M, Ferreira A, Carvalho D, Santisteban P. DuOx2 Promoter Regulation by Hormones, Transcriptional Factors and the Coactivator TAZ. Eur Thyroid J 2015; 4:6-13. [PMID: 25960956 PMCID: PMC4404926 DOI: 10.1159/000379749] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 02/06/2015] [Indexed: 01/13/2023] Open
Abstract
The production of H2O2, which is essential to thyroid hormone synthesis, involves two NADPH oxidases: dual oxidases 1 and 2 (DuOx1 and DuOx2). A functional study with human DuOx genes and their 5'-flanking regions showed that DuOx1 and -2 promoters are different from thyroid-specific gene promoters. Furthermore, their transcriptional activities are not restricted to thyroid cells. While regulation of Tg (thyroglobulin) and TPO (thyroperoxidase) expression have been extensively studied, DuOx2 promoter regulation by hormones and transcriptional factors need to be more explored. Herein we investigated the role of TSH, insulin and insulin-like growth factor 1 (IGF-1), as well as the cAMP effect on DuOx2 promoter (ptx41) activity in transfected rat thyroid cell lines (PCCL3). We also assessed DuOx2 promoter activity in the presence of transcriptional factors crucial to thyroid development such as TTF-1 (thyroid transcription factor 1), PAX8, CREB, DREAM, Nkx2.5 and the coactivator TAZ in HeLa and HEK 293T-transfected cells. Our results show that TSH and forskolin, which increase cAMP in thyroid cells, stimulated DuOx2 promoter activity. IGF-1 led to pronounced stimulation, while insulin induction was not statistically different from DuOx2 promoter basal activity. All transcriptional factors selected for this work and coactivator TAZ, except DREAM, stimulated DuOx2 promoter activity. Moreover, Nkx2.5 and TAZ synergistically increased DuOx2 promoter activity. In conclusion, we show that DuOx2 expression is regulated by hormones and transcription factors involved in thyroid organogenesis and carcinogenesis, reinforcing the importance of the control of H2O2 generation in the thyroid.
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Affiliation(s)
- L.C. Cardoso-Weide
- Departamento de Patologia, Faculdade de Medicina, Universidade Federal Fluminense (UFF), Niterói, Brazil
- *L.C. Cardoso-Weide, Departamento de Patologia, 4° andar, sala 4, Faculdade de Medicina, Hospital Universitário Antônio Pedro, Universidade Federal Fluminense (UFF), Rua Marques do Paraná, 303, Niterói, RJ 24033-900 (Brazil), E-Mail
| | - R.C. Cardoso-Penha
- Laboratório de Fisiologia Endócrina Doris Rosenthal, IBCCF, Rio de Janeiro, Brazil
| | - M.W. Costa
- Australian Regenerative Medicine Institute, Monash University, Melbourne, Vic., Australia
| | - A.C.F. Ferreira
- NUMPEX, Polo de Xerém, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
| | - D.P. Carvalho
- Laboratório de Fisiologia Endócrina Doris Rosenthal, IBCCF, Rio de Janeiro, Brazil
| | - P.S. Santisteban
- Instituto de Investigaciones Biomédicas Alberto Sols, Spanish Council of Research-Universidad Autónoma de Madrid, Madrid, Spain
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13
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Marcelli F, Boisset G, Schorderet DF. A dimerized HMX1 inhibits EPHA6/epha4b in mouse and zebrafish retinas. PLoS One 2014; 9:e100096. [PMID: 24945320 PMCID: PMC4063770 DOI: 10.1371/journal.pone.0100096] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2013] [Accepted: 05/22/2014] [Indexed: 12/29/2022] Open
Abstract
HMX1 is a homeobox-containing transcription factor implicated in eye development and responsible for the oculo-auricular syndrome of Schorderet-Munier-Franceschetti. HMX1 is composed of two exons with three conserved domains in exon 2, a homeobox and two domains called SD1 and SD2. The function of the latter two domains remains unknown. During retinal development, HMX1 is expressed in a polarized manner and thus seems to play a role in the establishment of retinal polarity although its exact role and mode of action in eye development are unknown. Here, we demonstrated that HMX1 dimerized and that the SD1 and homeodomains are required for this function. In addition, we showed that proper nuclear localization requires the presence of the homeodomain. We also identified that EPHA6, a gene implicated in retinal axon guidance, is one of its targets in eye development and showed that a dimerized HMX1 is needed to inhibit EPHA6 expression.
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Affiliation(s)
- Fabienne Marcelli
- IRO – Institute for Research in Ophthalmology, Sion, Switzerland
- Faculty of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland
| | - Gaëlle Boisset
- IRO – Institute for Research in Ophthalmology, Sion, Switzerland
| | - Daniel F. Schorderet
- IRO – Institute for Research in Ophthalmology, Sion, Switzerland
- Faculty of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland
- Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
- * E-mail:
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14
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Costa MW, Guo G, Wolstein O, Vale M, Castro ML, Wang L, Otway R, Riek P, Cochrane N, Furtado M, Semsarian C, Weintraub RG, Yeoh T, Hayward C, Keogh A, Macdonald P, Feneley M, Graham RM, Seidman JG, Seidman CE, Rosenthal N, Fatkin D, Harvey RP. Functional characterization of a novel mutation in NKX2-5 associated with congenital heart disease and adult-onset cardiomyopathy. ACTA ACUST UNITED AC 2013; 6:238-47. [PMID: 23661673 DOI: 10.1161/circgenetics.113.000057] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND The transcription factor NKX2-5 is crucial for heart development, and mutations in this gene have been implicated in diverse congenital heart diseases and conduction defects in mouse models and humans. Whether NKX2-5 mutations have a role in adult-onset heart disease is unknown. METHODS AND RESULTS Mutation screening was performed in 220 probands with adult-onset dilated cardiomyopathy. Six NKX2-5 coding sequence variants were identified, including 3 nonsynonymous variants. A novel heterozygous mutation, I184M, located within the NKX2-5 homeodomain, was identified in 1 family. A subset of family members had congenital heart disease, but there was an unexpectedly high prevalence of dilated cardiomyopathy. Functional analysis of I184M in vitro demonstrated a striking increase in protein expression when transfected into COS-7 cells or HL-1 cardiomyocytes because of reduced degradation by the Ubiquitin-proteasome system. In functional assays, DNA-binding activity of I184M was reduced, resulting in impaired activation of target genes despite increased expression levels of mutant protein. CONCLUSIONS Certain NKX2-5 homeodomain mutations show abnormal protein degradation via the Ubiquitin-proteasome system and partially impaired transcriptional activity. We propose that this class of mutation can impair heart development and mature heart function and contribute to NKX2-5-related cardiomyopathies with graded severity.
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Affiliation(s)
- Mauro W Costa
- Developmental and Stem Cell Biology Division, Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia.
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15
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Makhoul G, Chiu RCJ, Cecere R. Placental mesenchymal stem cells: a unique source for cellular cardiomyoplasty. Ann Thorac Surg 2013; 95:1827-33. [PMID: 23541427 DOI: 10.1016/j.athoracsur.2012.11.053] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Revised: 11/15/2012] [Accepted: 11/16/2012] [Indexed: 02/06/2023]
Abstract
In coronary heart disease, the use of stem cells for regeneration purposes has been broadly studied. Whereas bone marrow mesenchymal stem cells remain the most extensively investigated, other cell sources have been reported. Here we discuss and compare the characteristics of placenta-derived mesenchymal stem cells as a novel alternative cell source for cellular cardiomyoplasty. These cells are isolated from the human term placenta, which is normally discarded post partum. With their lack of ethical conflicts and young age, the readily available placenta-derived mesenchymal stem cells could be more suitable for myocardial regenerative therapy.
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Affiliation(s)
- Georges Makhoul
- Divisions of Cardiac and Experimental Surgery, McGill University Health Center, Montreal, Quebec, Canada
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16
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Clark CD, Zhang B, Lee B, Evans SI, Lassar AB, Lee KH. Evolutionary conservation of Nkx2.5 autoregulation in the second heart field. Dev Biol 2013; 374:198-209. [PMID: 23165293 PMCID: PMC3549048 DOI: 10.1016/j.ydbio.2012.11.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Revised: 10/22/2012] [Accepted: 11/09/2012] [Indexed: 11/28/2022]
Abstract
The cardiac homeobox gene Nkx2.5 plays a key and dosage-sensitive role in the differentiation of outflow tract and right ventricle from progenitors of the second heart field (SHF) and Nkx2.5 mutation is strongly associated with human outflow tract congenital heart disease (OFT CHD). Therefore defining the regulatory mechanisms controlling Nkx2.5 expression in SHF populations serves an important function in understanding the etiology of complex CHD. Through a comparative analysis of regulatory elements controlling SHF expression of Nkx2.5 in the chicken and mouse, we have found evidence that Nkx2.5 autoregulation is important for maintaining Nkx2.5 expression during SHF differentiation in both species. However the mechanism of Nkx2.5 maintenance differs between placental mammals and non-mammalian vertebrates: in chick Nkx2.5 binds directly to a genomic enhancer element that is required to maintain Nkx2.5 expression in the SHF. In addition, it is likely that this is true in other non-mammalian vertebrates given that they possess a similar genomic organization. By contrast, in placental mammals, Nkx2.5 autoregulation in the SHF functions indirectly through Mef2c. These data underscore a tight relationship in mammals between Nkx2.5 and Mef2c in SHF transcriptional regulation, and highlight the potential for evolutionary cis-regulatory analysis to identify core, conserved components of the gene networks controlling heart development.
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Affiliation(s)
- Christopher D. Clark
- Regenerative Medicine, Cell Biology and Anatomy Department, Medical University of South Carolina, Charleston, SC
| | - Boding Zhang
- Regenerative Medicine, Cell Biology and Anatomy Department, Medical University of South Carolina, Charleston, SC
| | - Benjamin Lee
- Regenerative Medicine, Cell Biology and Anatomy Department, Medical University of South Carolina, Charleston, SC
| | - Samuel I. Evans
- Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA
| | - Andrew B. Lassar
- Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA
| | - Kyu-Ho Lee
- Regenerative Medicine, Cell Biology and Anatomy Department, Medical University of South Carolina, Charleston, SC
- Department of Pediatrics, Division of Pediatric Cardiology, Children’s Hospital, Medical University of South Carolina, Charleston, SC
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17
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Abstract
Differentiated adult cardiomyocytes (CMs) lack significant regenerative potential, which is one reason why degenerative heart diseases are the leading cause of death in the western world. For future cardiac repair, stem cell-based therapeutic strategies may become alternatives to donor heart transplantation. The principle of reprogramming adult terminally differentiated cells (iPSC) had a major impact on stem cell biology. One can now generate autologous pluripotent cells that highly resemble embryonic stem cells (ESC) and that are ethically inoffensive as opposed to human ESC. Yet, due to genetic and epigenetic aberrations arising during the full reprogramming process, it is questionable whether iPSC will enter the clinic in the near future. Therefore, the recent achievement of directly reprogramming fibroblasts into cardiomyocytes via a milder approach, thereby avoiding an initial pluripotent state, may become of great importance. In addition, various clinical scenarios will depend on the availability of specific cardiac cellular subtypes, for which a first step was achieved via our own programming approach to achieve cardiovascular cell subtypes. In this review, we discuss recent progress in the cardiovascular stem cell field addressing the above mentioned aspects.
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Affiliation(s)
- Robert David
- 1st Medical Department, University of Munich, Campus Grosshadern, Munich, Germany
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18
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Pradhan L, Genis C, Scone P, Weinberg EO, Kasahara H, Nam HJ. Crystal structure of the human NKX2.5 homeodomain in complex with DNA target. Biochemistry 2012; 51:6312-9. [PMID: 22849347 PMCID: PMC3448007 DOI: 10.1021/bi300849c] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
NKX2.5 is a homeodomain containing transcription factor regulating cardiac formation and function, and its mutations are linked to congenital heart disease. Here we provide the first report of the crystal structure of the NKX2.5 homeodomain in complex with double-stranded DNA of its endogenous target, locating within the proximal promoter -242 site of the atrial natriuretic factor gene. The crystal structure, determined at 1.8 Å resolution, demonstrates that NKX2.5 homeodomains occupy both DNA binding sites separated by five nucleotides without physical interaction between themselves. The two homeodomains show identical conformation despite the differences in the DNA sequences they bind, and no significant bending of the DNA was observed. Tyr54, absolutely conserved in NK2 family proteins, mediates sequence-specific interaction with the TAAG motif. This high resolution crystal structure of NKX2.5 protein provides a detailed picture of protein and DNA interactions, which allows us to predict DNA binding of mutants identified in human patients.
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Affiliation(s)
- Lagnajeet Pradhan
- Department of Bioengineering, University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Caroli Genis
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida 32610, United States
| | - Peyton Scone
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida 32610, United States
| | - Ellen O. Weinberg
- Cardiovascular Research, Boston University Medical Center, Boston, Massachusetts 02118, United States
| | - Hideko Kasahara
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida 32610, United States
| | - Hyun-Joo Nam
- Department of Bioengineering, University of Texas at Dallas, Richardson, Texas 75080, United States,Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida 32610, United States,Corresponding Author: Address: University of Texas at Dallas, 800 W Campbell Road, RL10, Richardson, TX 75080. Telephone: (972) 883-5786.
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19
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Papadopoulos DK, Skouloudaki K, Adachi Y, Samakovlis C, Gehring WJ. Dimer formation via the homeodomain is required for function and specificity of Sex combs reduced in Drosophila. Dev Biol 2012; 367:78-89. [DOI: 10.1016/j.ydbio.2012.04.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Revised: 04/12/2012] [Accepted: 04/16/2012] [Indexed: 10/28/2022]
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20
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Mamede AC, Carvalho MJ, Abrantes AM, Laranjo M, Maia CJ, Botelho MF. Amniotic membrane: from structure and functions to clinical applications. Cell Tissue Res 2012; 349:447-58. [PMID: 22592624 DOI: 10.1007/s00441-012-1424-6] [Citation(s) in RCA: 231] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Accepted: 03/25/2012] [Indexed: 12/11/2022]
Abstract
Amniotic membrane (AM) or amnion is a thin membrane on the inner side of the fetal placenta; it completely surrounds the embryo and delimits the amniotic cavity, which is filled by amniotic liquid. In recent years, the structure and function of the amnion have been investigated, particularly the pluripotent properties of AM cells, which are an attractive source for tissue transplantation. AM has anti-inflammatory, anti-bacterial, anti-viral and immunological characteristics, as well as anti-angiogenic and pro-apoptotic features. AM is a promoter of epithelialization and is a non-tumorigenic tissue and its use has no ethical problems. Because of its attractive properties, AM has been applied in several surgical procedures related to ocular surface reconstruction and the genito-urinary tract, skin, head and neck, among others. So far, the best known and most auspicious applications of AM are ocular surface reconstruction, skin applications and tissue engineering. However, AM can also be applied in oncology. In this area, AM can prevent the delivery of nutrients and oxygen to cancer cells and consequently interfere with tumour angiogenesis, growth and metastasis.
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Affiliation(s)
- A C Mamede
- Biophysics Unit, IBILI, Faculty of Medicine, University of Coimbra, Coimbra, Portugal.
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21
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Pandorf CE, Jiang W, Qin AX, Bodell PW, Baldwin KM, Haddad F. Regulation of an antisense RNA with the transition of neonatal to IIb myosin heavy chain during postnatal development and hypothyroidism in rat skeletal muscle. Am J Physiol Regul Integr Comp Physiol 2012; 302:R854-67. [PMID: 22262309 DOI: 10.1152/ajpregu.00591.2011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Postnatal development of fast skeletal muscle is characterized by a transition in expression of myosin heavy chain (MHC) isoforms, from primarily neonatal MHC at birth to primarily IIb MHC in adults, in a tightly coordinated manner. These isoforms are encoded by distinct genes, which are separated by ∼17 kb on rat chromosome 10. The neonatal-to-IIb MHC transition is inhibited by a hypothyroid state. We examined RNA products [mRNA, pre-mRNA, and natural antisense transcript (NAT)] of developmental and adult-expressed MHC genes (embryonic, neonatal, I, IIa, IIx, and IIb) at 2, 10, 20, and 40 days after birth in normal and thyroid-deficient rat neonates treated with propylthiouracil. We found that a long noncoding antisense-oriented RNA transcript, termed bII NAT, is transcribed from a site within the IIb-Neo intergenic region and across most of the IIb MHC gene. NATs have previously been shown to mediate transcriptional repression of sense-oriented counterparts. The bII NAT is transcriptionally regulated during postnatal development and in response to hypothyroidism. Evidence for a regulatory mechanism is suggested by an inverse relationship between IIb MHC and bII NAT in normal and hypothyroid-treated muscle. Neonatal MHC transcription is coordinately expressed with bII NAT. A comparative phylogenetic analysis also suggests that bII NAT-mediated regulation has been a conserved trait of placental mammals for most of the eutherian evolutionary history. The evidence in support of the regulatory model implicates long noncoding antisense RNA as a mechanism to coordinate the transition between neonatal and IIb MHC during postnatal development.
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Affiliation(s)
- Clay E Pandorf
- Dept. of Physiology and Biophysics, Univ. of California, Irvine, Irvine, CA 92697, USA.
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22
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Shi X, Gupta S, Rashotte AM. Solanum lycopersicum cytokinin response factor (SlCRF) genes: characterization of CRF domain-containing ERF genes in tomato. JOURNAL OF EXPERIMENTAL BOTANY 2012; 63:973-82. [PMID: 22068146 PMCID: PMC3254692 DOI: 10.1093/jxb/err325] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2010] [Revised: 09/13/2011] [Accepted: 09/16/2011] [Indexed: 05/21/2023]
Abstract
Cytokinin is an influential hormone in growth and developmental processes across many plant species. While several cytokinin-regulated genes have been well characterized in Arabidopsis, few have been identified in tomato, Solanum lycopersicum. Here a tomato family of 11 highly related cytokinin response factor genes designated as SlCRF1-SlCRF11 (Solanum lycopersicum cytokinin response factor) are identified and characterized. SlCRFs are AP2/ERF transcription factors and generally orthologous to Arabidopsis CRF clade members (AtCRFs). Some SlCRF genes lack a direct Arabidopsis orthologue and one SlCRF has a unique protein domain arrangement not seen in any other CRF protein. Expression analysis of SlCRF1-SlCRF11 revealed differential patterns and levels across plant tissues examined (leaf, stem, root and flower). Several SlCRFs show induction by cytokinin to various degrees, similar to AtCRFs. Additionally it is shown that some SlCRFs can be regulated by other factors, including NaCl, ethylene, methyl jasmonate, and salicylic acid. Examination of SlCRF proteins in transient Agrobacterium infiltration experiments indicates they can be nuclear localized in planta. Using a bimolecular fluorescence complementation (split-yellow fluorescent protein) system, it is also shown that SlCRF proteins can interact to form homo- and heterodimers. Overall this work indicates that some SlCRFs resemble previously identified CRFs in terms of structure, expression, and cytokinin regulation. However, SlCRFs have novel CRF protein forms and responses to abiotic factors, suggesting they may have a diverse set of roles in stress and hormone regulation in tomato.
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23
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Pereira LA, Wong MS, Lim SM, Sides A, Stanley EG, Elefanty AG. Brachyury and related Tbx proteins interact with the Mixl1 homeodomain protein and negatively regulate Mixl1 transcriptional activity. PLoS One 2011; 6:e28394. [PMID: 22164283 PMCID: PMC3229578 DOI: 10.1371/journal.pone.0028394] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Accepted: 11/07/2011] [Indexed: 02/07/2023] Open
Abstract
Mixl1 is a homeodomain transcription factor required for mesoderm and endoderm patterning during mammalian embryogenesis. Despite its crucial function in development, co-factors that modulate the activity of Mixl1 remain poorly defined. Here we report that Mixl1 interacts physically and functionally with the T-box protein Brachyury and related members of the T-box family of transcription factors. Transcriptional and protein analyses demonstrated overlapping expression of Mixl1 and Brachyury during embryonic stem cell differentiation. In vitro protein interaction studies showed that the Mixl1 with Brachyury associated via their DNA-binding domains and gel shift assays revealed that the Brachyury T-box domain bound to Mixl1-DNA complexes. Furthermore, luciferase reporter experiments indicated that association of Mixl1 with Brachyury and related T-box factors inhibited the transactivating potential of Mixl1 on the Gsc and Pdgfrα promoters. Our results indicate that the activity of Mixl1 can be modulated by protein-protein interactions and that T-box factors can function as negative regulators of Mixl1 activity.
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Affiliation(s)
- Lloyd A. Pereira
- Differentiation and Transcription Laboratory, Peter MacCallum Cancer Centre and the Pathology Department, The University of Melbourne, Melbourne, Victoria, Australia
| | - Michael S. Wong
- Monash Immunology and Stem Cell Laboratories, Monash University, Clayton, Victoria, Australia
| | - Sue Mei Lim
- Monash Immunology and Stem Cell Laboratories, Monash University, Clayton, Victoria, Australia
| | - Alexandra Sides
- Monash Immunology and Stem Cell Laboratories, Monash University, Clayton, Victoria, Australia
| | - Edouard G. Stanley
- Monash Immunology and Stem Cell Laboratories, Monash University, Clayton, Victoria, Australia
- * E-mail: (AGE); (EGS)
| | - Andrew G. Elefanty
- Monash Immunology and Stem Cell Laboratories, Monash University, Clayton, Victoria, Australia
- * E-mail: (AGE); (EGS)
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24
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Differential role of Nkx2-5 in activation of the atrial natriuretic factor gene in the developing versus failing heart. Mol Cell Biol 2011; 31:4633-45. [PMID: 21930795 DOI: 10.1128/mcb.05940-11] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Atrial natriuretic factor (ANF) is abundantly expressed in atrial cardiomyocytes throughout ontogeny and in ventricular cardiomyocytes in the developing heart. However, during cardiac failure and hypertrophy, ANF expression can reappear in adult ventricular cardiomyocytes. The transcription factor Nkx2-5 is one of the major transactivators of the ANF gene in the developing heart. We identified Nkx2-5 binding at three 5' regulatory elements (kb -34, -31, and -21) and at the proximal ANF promoter by ChIP assay using neonatal mouse cardiomyocytes. 3C analysis revealed close proximity between the distal elements and the promoter region. A 5.8-kb fragment consisting of these elements transactivated a reporter gene in vivo recapitulating endogenous ANF expression, which was markedly reduced in tamoxifen-inducible Nkx2-5 gene knockout mice. However, expression of a reporter gene was increased and expanded toward the outer compact layer in the absence of the transcription repressor Hey2, similar to endogenous ANF expression. Functional Nkx2-5 and Hey2 binding sites separated by 59 bp were identified in the -34 kb element in neonatal cardiomyocytes. In adult hearts, this fragment did not respond to pressure overload, and ANF was induced in the absence of Nkx2-5. These results demonstrate that Nkx2-5 and its responsive cis-regulatory DNA elements are essential for ANF expression selectively in the developing heart.
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25
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Mutations of the GATA4 and NKX2.5 genes in Chinese pediatric patients with non-familial congenital heart disease. Genetica 2010; 138:1231-40. [PMID: 21110066 DOI: 10.1007/s10709-010-9522-4] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2010] [Accepted: 11/04/2010] [Indexed: 12/19/2022]
Abstract
A number of mutations in GATA4 and NKX2.5 have been identified to be causative for a subset of familial congenital heart defects (CHDs) and a small number of sporadic CHDs. In this study, we evaluated common GATA4 and NKX2.5 mutations in 135 Chinese pediatric patients with non-familial congenital heart defects. Two novel mutations in the coding region of GATA4 were identified, namely, 487C >T (Pro163Ser) in exon 1 in a child with tetralogy of Fallot and 1220C >A (Pro407Gln) in exon 6 in a pediatric patient with outlet membranous ventricular septal defect. We also found 848C >A (Pro283Gln) in exon 2 of the NKX2.5 gene in a pediatric patient with ventricular septal defect, patent ductus arteriosus and aortic isthmus stenosis. None of the mutations was detected in healthy control subjects (n = 114). This study suggests that GATA4 and NKX2.5 missense mutations may be associated with congenital heart defects in pediatric Chinese patients. Further clinical studies with large samples are warranted.
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26
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Ouyang P, Saarel E, Bai Y, Luo C, Lv Q, Xu Y, Wang F, Fan C, Younoszai A, Chen Q, Tu X, Wang QK. A de novo mutation in NKX2.5 associated with atrial septal defects, ventricular noncompaction, syncope and sudden death. Clin Chim Acta 2010; 412:170-5. [PMID: 20932824 DOI: 10.1016/j.cca.2010.09.035] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2010] [Revised: 09/06/2010] [Accepted: 09/29/2010] [Indexed: 01/30/2023]
Abstract
BACKGROUND Mutations in transcription factor NKX2.5 cause congenital heart disease (CHD). We identified a CHD family with atrial septal defects (ASDs), atrioventricular block, ventricular noncompaction, syncope and sudden death. Our objective is to identify the disease-causing mutation in the CHD family. METHODS Direct DNA sequence analysis was used to identify the CHD mutation. The functional effects of the mutation were characterized by a luciferase reporter assay and immunostaining. RESULTS A novel, de novo 2-bp insertion (c.512insGC) was identified in exon 2 of NKX2.5. Mutation c.512insGC co-segregates with CHD in the family, and is not present in 200 controls. Functional studies indicate that the c.512insGC mutation impedes nuclear localization of NKX2.5 and causes a total loss of transactivation activity of NKX2.5. Furthermore, no NKX2.5 mutation was identified in 125 sporadic Chinese CHD patients. CONCLUSIONS (1) NKX2.5 mutation c.512insGC is associated with ASDs, syncope and sudden death. It is the second de novo mutation identified in NKX2.5. (2) NKX2.5 mutations are rare in sporadic CHD patients. (3) This study for the first time identifies association between a NKX2.5 mutation and ventricular noncompaction. Our results significantly expand the phenotypic spectrum of NKX2.5 mutations.
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Affiliation(s)
- Ping Ouyang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, and Center for Human Genome Research, Cardio-X Institute, Huazhong University of Science and Technology, Wuhan, PR China
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27
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Barth JL, Clark CD, Fresco VM, Knoll EP, Lee B, Argraves WS, Lee KH. Jarid2 is among a set of genes differentially regulated by Nkx2.5 during outflow tract morphogenesis. Dev Dyn 2010; 239:2024-33. [PMID: 20549724 DOI: 10.1002/dvdy.22341] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Nkx2.5, a transcription factor implicated in human congenital heart disease, is required for regulation of second heart field (SHF) progenitors contributing to outflow tract (OFT). Here, we define a set of genes (Lrrn1, Elovl2, Safb, Slc39a6, Khdrbs1, Hoxb4, Fez1, Ccdc117, Jarid2, Nrcam, and Enpp3) expressed in SHF containing pharyngeal arch tissue whose regulation is dependent on Nkx2.5. Further investigation shows that Jarid2, which has been implicated in OFT morphogenesis, is a direct target of Nkx2.5 regulation. Jarid2 expression was up-regulated in SHF mesoderm of Nkx2.5-deficient embryos. Chromatin immunoprecipitation analysis showed Nkx2.5 interaction with consensus binding sites in the Jarid2 promoter in pharyngeal arch cells. Finally, Jarid2 promoter activity and mRNA expression levels were down-regulated by Nkx2.5 overexpression. Given the role of Jarid2 as a regulator of early cardiac proliferation, these findings highlight Jarid2 as one of several potential mediators of the critical role played by Nkx2.5 during OFT morphogenesis.
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Affiliation(s)
- Jeremy L Barth
- Regenerative Medicine and Cell Biology Department, Medical University of South Carolina,173 Ashley Avenue, Charleston, SC 29425, USA
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28
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Antonella Cecchetto, Alessandra Rampazzo, Annalisa Angelini,. From molecular mechanisms of cardiac development to genetic substrate of congenital heart diseases. Future Cardiol 2010; 6:373-93. [DOI: 10.2217/fca.10.10] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Congenital heart disease is one of the most important chapters in medicine because its incidence is increasing and nowadays it is close to 1.2%. Most congenital heart disorders are the result of defects during embryogenesis, which implies that they are due to alterations in genes involved in cardiac development. This review summarizes current knowledge regarding the molecular mechanisms involved in cardiac development in order to clarify the genetic basis of congenital heart disease.
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29
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Bartlett H, Veenstra GJC, Weeks DL. Examining the cardiac NK-2 genes in early heart development. Pediatr Cardiol 2010; 31:335-41. [PMID: 19967350 PMCID: PMC2981039 DOI: 10.1007/s00246-009-9605-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2009] [Accepted: 11/11/2009] [Indexed: 12/14/2022]
Abstract
The cardiac NK-2 transcription factors are the vertebrate relatives of the Drosophila tinman gene. Without the Drosophila tinman gene, fruit flies fail to form their heart ("dorsal vessel"), and mutations or altered expression of cardiac NK-2 genes may lead to abnormal heart formation in vertebrates. Although the cardiac NK-2 gene NKX2-5 is recognized as an important factor in cases of human congenital heart disease and heart development in vertebrates, the roles of the other cardiac NK-2 genes are less clear. This report reviews what is known about the cardiac NK-2 genes in cardiac development, comparing studies in several different model systems.
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Affiliation(s)
- Heather Bartlett
- Department of Pediatrics, University of Iowa, Bowen Science Building, 51 Newton Road, Iowa City, IA 52242, USA
| | - Gert Jan C. Veenstra
- Department of Molecular Biology, Faculty of Science, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Daniel L. Weeks
- Department of Biochemistry, University of Iowa, Bowen Science Building, 51 Newton Road, Iowa City, IA 52242, USA,
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30
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Neuroblastoma phox2b variants stimulate proliferation and dedifferentiation of immature sympathetic neurons. J Neurosci 2010; 30:905-15. [PMID: 20089899 DOI: 10.1523/jneurosci.5368-09.2010] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Neuroblastoma is a pediatric tumor that is thought to arise from autonomic precursors in the neural crest. Mutations in the PHOX2B gene have been observed in familial and sporadic forms of neuroblastoma and represent the first defined genetic predisposition for neuroblastoma. Here, we address the mechanisms that may underlie this predisposition, comparing the function of wild-type and mutant Phox2b proteins ectopically expressed in proliferating, embryonic sympathetic neurons. Phox2b displays a strong antiproliferative effect, which is lost in all Phox2b neuroblastoma variants analyzed. In contrast, an increase in sympathetic neuron proliferation is elicited by Phox2b variants with mutations in the homeodomain when endogenous Phox2b levels are lowered by siRNA-mediated knockdown to mimic the situation of heterozygous PHOX2B mutations in neuroblastoma. The increased proliferation is blocked by Hand2 knockdown and the antiproliferative Phox2b effects are rescued by Hand2 overexpression, implying Hand2 in Phox2b-mediated proliferation control. A Phox2b variant with a nonsense mutation in the homeodomain elicits, in addition, a decreased expression of characteristic marker genes. Together, these results suggest that PHOX2B mutations predispose to neuroblastoma by increasing proliferation and promoting dedifferentiation of cells in the sympathoadrenergic lineage.
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31
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Anderson KR, Torres CA, Solomon K, Becker TC, Newgard CB, Wright CV, Hagman J, Sussel L. Cooperative transcriptional regulation of the essential pancreatic islet gene NeuroD1 (beta2) by Nkx2.2 and neurogenin 3. J Biol Chem 2009; 284:31236-48. [PMID: 19759004 DOI: 10.1074/jbc.m109.048694] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Nkx2.2 and NeuroD1 are two critical regulators of pancreatic beta cell development. Nkx2.2 is a homeodomain transcription factor that is essential for islet cell type specification and mature beta cell function. NeuroD1 is a basic helix-loop-helix transcription factor that is critical for islet beta cell maturation and maintenance. Although both proteins influence beta cell development directly downstream of the endocrine progenitor factor, neurogenin3 (Ngn3), a connection between the two proteins in the regulation of beta cell fate and function has yet to be established. In this study, we demonstrate that Nkx2.2 transcriptional activity is required to facilitate the activation of NeuroD1 by Ngn3. Furthermore, Nkx2.2 is necessary to maintain high levels of NeuroD1 expression in developing mouse and zebrafish islets and in mature beta cells. Interestingly, Nkx2.2 regulates NeuroD1 through two independent promoter elements, one that is bound and activated directly by Nkx2.2 and one that appears to be regulated by Nkx2.2 through an indirect mechanism. Together, these findings suggest that Nkx2.2 coordinately activates NeuroD1 with Ngn3 within the endocrine progenitor cell and also plays a role in the maintenance of NeuroD1 expression to regulate beta cell function in the mature islet. Collectively, these findings further define the conserved regulatory networks involved in islet beta cell formation and function.
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Affiliation(s)
- Keith R Anderson
- Department of Biochemistry, University of Colorado Health Science Center, Denver, Colorado 80045, USA
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32
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Esposito G, Grutter G, Drago F, Costa MW, De Santis A, Bosco G, Marino B, Bellacchio E, Lepri F, Harvey RP, Sarkozy A, Dallapiccola B. Molecular analysis of PRKAG2, LAMP2, and NKX2-5 genes in a cohort of 125 patients with accessory atrioventricular connection. Am J Med Genet A 2009; 149A:1574-7. [PMID: 19533775 DOI: 10.1002/ajmg.a.32907] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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33
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Chang DF, Tsai SC, Wang XC, Xia P, Senadheera D, Lutzko C. Molecular characterization of the human NANOG protein. Stem Cells 2009; 27:812-21. [PMID: 19350681 DOI: 10.1634/stemcells.2008-0657] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
NANOG is a key transcriptional regulator of pluripotent stem cell (PSC) self-renewal. NANOG occupies promoters that are active and others that are repressed during self-renewal; however, the mechanisms by which NANOG regulates transcriptional repression and activation are unknown. We hypothesized that individual protein domains of NANOG control its interactions with both the promoters and its coregulators. We performed a detailed characterization of the functional domains in the human (h) NANOG protein, using a panel of deletion-mutant and point-mutant constructs. We determined that six amino acids in the homeodomain ((136)YKQVKT(141)) are sufficient for the nuclear localization of hNANOG. We also determined that the tryptophan-rich region (W) of hNANOG contains a CRM1-independent signal for nuclear export, suggesting a possible cellular shuttling behavior that has not been reported for hNANOG. We also show that at least four tryptophans are required for nuclear export. We also determined that similar to murine (m) NANOG, the W region of hNANOG contains a homodimerization domain. Finally, in vitro transactivation analyses identified distinct regions that enhance or diminish activity at gene promoters that are active during self-renewal. Specifically, the N-terminal region interferes with transcription and removal of this region that produced a "super-active" hNANOG with enhanced transcriptional activity. We also confirmed that the transcriptional activator in hNANOG is contained in the C-terminal region, similar to murine NANOG. In summary, this study has characterized the structure and function of hNANOG protein leading to an increased understanding of the mechanism by which hNANOG regulates both transcriptional activation and repression during PSC self-renewal.
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Affiliation(s)
- David F Chang
- Department of Pediatrics, Division of Research Immunology/Bone Marrow Transplantation, Saban Research Institute at Childrens Hospital Los Angles, University of Southern California, Los Angeles, California, USA
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34
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Hazelett DJ, Lakeland DL, Weiss JB. Affinity Density: a novel genomic approach to the identification of transcription factor regulatory targets. Bioinformatics 2009; 25:1617-24. [PMID: 19401399 PMCID: PMC2732317 DOI: 10.1093/bioinformatics/btp282] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Methods: A new method was developed for identifying novel transcription factor regulatory targets based on calculating Local Affinity Density. Techniques from the signal-processing field were used, in particular the Hann digital filter, to calculate the relative binding affinity of different regions based on previously published in vitro binding data. To illustrate this approach, the complete genomes of Drosophila melanogaster and D.pseudoobscura were analyzed for binding sites of the homeodomain proteinc Tinman, an essential heart development gene in both Drosophila and Mouse. The significant binding regions were identified relative to genomic background and assigned to putative target genes. Valid candidates common to both species of Drosophila were selected as a test of conservation. Results: The new method was more sensitive than cluster searches for conserved binding motifs with respect to positive identification of known Tinman targets. Our Local Affinity Density method also identified a significantly greater proportion of Tinman-coexpressed genes than equivalent, optimized cluster searching. In addition, this new method predicted a significantly greater than expected number of genes with previously published RNAi phenotypes in the heart. Availability: Algorithms were implemented in Python, LISP, R and maxima, using MySQL to access locally mirrored sequence data from Ensembl (D.melanogaster release 4.3) and flybase (D.pseudoobscura). All code is licensed under GPL and freely available at http://www.ohsu.edu/cellbio/dev_biol_prog/affinitydensity/. Contact:hazelett@ohsu.edu
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Affiliation(s)
- Dennis J Hazelett
- Integrative Biosciences, Oregon Health and Science University, 611 SW Campus Drive, Portland, OR 97239, USA.
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35
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Vincentz JW, Barnes RM, Firulli BA, Conway SJ, Firulli AB. Cooperative interaction of Nkx2.5 and Mef2c transcription factors during heart development. Dev Dyn 2009; 237:3809-19. [PMID: 19035347 DOI: 10.1002/dvdy.21803] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The interactions of diverse transcription factors mediate the molecular programs that regulate mammalian heart development. Among these, Nkx2.5 and the Mef2c regulate common downstream targets and exhibit striking phenotypic similarities when disrupted, suggesting a potential interaction during heart development. Co-immunoprecipitation and mammalian two-hybrid experiments revealed a direct molecular interaction between Nkx2.5 and Mef2c. Assessment of mRNA expression verified spatiotemporal cardiac coexpression. Finally, genetic interaction studies employing histological and molecular analyses showed that, although Nkx2.5(-/-) and Mef2c(-/-) individual mutants both have identifiable ventricles, Nkx2.5(-/-);Mef2c(-/-) double mutants do not, and that mutant cardiomyocytes express only atrial and second heart field markers. Molecular marker and cell death and proliferation analyses provide evidence that ventricular hypoplasia is the result of defective ventricular cell differentiation. Collectively, these data support a hypothesis where physical, functional, and genetic interactions between Nkx2.5 and Mef2c are necessary for ventricle formation.
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Affiliation(s)
- Joshua W Vincentz
- Riley Heart Research Center, Herman B Wells Center for Pediatric Research Division of Pediatrics Cardiology, Department of Anatomy, Indiana Medical School, Indianapolis, Indiana 46202-5225, USA
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36
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Genis C, Scone P, Kasahara H, Nam HJ. Crystallization and preliminary X-ray analysis of the NKX2.5 homeodomain in complex with DNA. Acta Crystallogr Sect F Struct Biol Cryst Commun 2008; 64:1079-82. [PMID: 18997347 PMCID: PMC2581709 DOI: 10.1107/s1744309108033447] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2008] [Accepted: 10/14/2008] [Indexed: 11/11/2022]
Abstract
As part of an effort to elucidate the molecular basis for the pathogenesis of NKX2.5 mutations in congenital heart disease using X-ray crystallography, the NKX2.5 homeodomain has been crystallized in complex with a specific DNA element, the -242 promoter region of atrial natriuretic factor. Crystals of the homeodomain-DNA complex diffracted X-rays to 1.7 A resolution and belonged to space group P6(5), with unit-cell parameters a = b = 71.5, c = 94.3 A. The asymmetric unit contained two molecules of the NKX2.5 homeodomain and one double-stranded oligonucleotide.
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Affiliation(s)
- Caroli Genis
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL 32610, USA
| | - Peyton Scone
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL 32610, USA
| | - Hideko Kasahara
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, FL 32610, USA
| | - Hyun-Joo Nam
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL 32610, USA
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37
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Wang J, Zhang H, Iyer D, Feng XH, Schwartz RJ. Regulation of cardiac specific nkx2.5 gene activity by small ubiquitin-like modifier. J Biol Chem 2008; 283:23235-43. [PMID: 18579533 DOI: 10.1074/jbc.m709748200] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The cardiac specific homeobox gene nkx2.5, a member of the nk-2 class family, plays a central role in cardiogenesis and is a target of the small ubiquitin-like modifier (SUMO). Nkx2.5 was modified by SUMO on its 51st amino acid, a lysine residue conserved across species but absent in other nk-2 members. Conversion of this lysine to an arginine (K51R) substantially reduced Nkx2.5 DNA binding and also its transcriptional activity. Unexpectedly, mutant K51R was targeted by ubiquitin. E3 ligase PIAS proteins PIAS1, PIASx, and PIASy, but not PIAS3, enhanced SUMO-1 attachment to Nkx2.5 on the primary SUMO acceptor site. SUMO-2 linkage to Nkx2.5 was catalyzed only by PIASx and not by other PIAS proteins. SUMO conjugation stabilized the formation of Nkx2.5-containing complexes that led to robust transcriptional activation. Thus, SUMO modification serves as a positive regulator for Nkx2.5 transcriptional activity.
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Affiliation(s)
- Jun Wang
- Institute of Biosciences and Technology, Texas A & M Health Science Center, Houston, Texas 77030, USA.
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38
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Abstract
The defining activity of the homeodomain protein Nanog is the ability to confer cytokine-independent self-renewal upon ES (embryonic stem) cells in which it is overexpressed. However, the biochemical basis by which Nanog achieves this function remains unknown. In the present study, we show that Nanog dimerizes through a functionally critical domain. Co-immunoprecipitation of Nanog molecules tagged with distinct epitopes demonstrates that Nanog self-associates through a region in which every fifth residue is tryptophan. In vitro binding experiments establish that this region participates directly in self-association. Moreover, analytical ultracentrifugation indicates that, in solution, Nanog is in equilibrium between monomeric and dimeric forms with a K(d) of 3 muM. The functional importance of Nanog dimerization is established by ES cell colony-forming assays in which deletion of the tryptophan-repeat region eliminates the capacity of Nanog to direct LIF (leukaemia inhibitory factor)-independent self-renewal.
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39
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Requirement of Nanog dimerization for stem cell self-renewal and pluripotency. Proc Natl Acad Sci U S A 2008; 105:6326-31. [PMID: 18436640 DOI: 10.1073/pnas.0802288105] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Pluripotency of embryonic stem (ES) cells is maintained by transcription factors that form a highly interconnected protein interaction network surrounding the homeobox protein Nanog. Enforced expression of Nanog in mouse ES (mES) cells promotes self-renewal and alleviates their requirement for leukemia inhibitory factor (LIF). Understanding molecular mechanisms by which Nanog functions should illuminate fundamental properties of stem cells and the process of cellular reprogramming. Previously, we showed that Nanog forms multiple protein complexes in mES cells. Here, we demonstrate that Nanog dimerizes through its C-terminal domain rather than the homeodomain. Dimerization is required for interaction with other pluripotency network proteins. We also show that enforced expression of the Nanog dimer, but not the monomer, functionally replaces wild-type Nanog to sustain LIF-independent self-renewal of ES cells. Our results demonstrate that Nanog-Nanog homodimerization is a critical aspect of its function promoting stem cell pluripotency.
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40
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Lim JY, Kim WH, Kim J, Park SI. Induction of Id2 expression by cardiac transcription factors GATA4 and Nkx2.5. J Cell Biochem 2008; 103:182-94. [PMID: 17559079 DOI: 10.1002/jcb.21396] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Inhibitor of differentiation/DNA binding (Id) proteins function as a regulator of helix-loop-helix proteins participating in cell lineage commitment and differentiation. Here, we observed a marked induction of Id2 during cardiomyocyte differentiation from P19CL6 murine embryonic teratocarcinoma stem cells, prompting us to investigate the upstream regulatory mechanism of Id2 induction. Computer analysis of Id2 promoter and subsequent electrophoretic mobility shift assay revealed several binding sites for GATA4 and Nkx2.5 within the Id2 promoter. By further deletion and mutation analysis of the respective binding site, we identified that two motifs located at -497/-502 and -264/-270 were functionally important for Id2 promoter activation by GATA4 and Nkx2.5, respectively. Overexpression of GATA4 and/or Nkx2.5 induced not only Id2 promoter activity but also Id2 protein expression. Additionally, Id proteins significantly inhibit the GATA4 and Nkx2.5-dependent transcription, suggesting Id proteins may play a regulatory role in cardiogenesis. Collectively, our results demonstrate that GATA4 and Nkx2.5 could be one of the upstream regulators of Id2.
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Affiliation(s)
- Joong-Yeon Lim
- Division of Intractable Diseases, Center for Biomedical Sciences, National Institute of Health, 194, Tongillo, Eunpyeong-gu, Seoul 122-701, Korea
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41
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Torres J, Watt FM. Nanog maintains pluripotency of mouse embryonic stem cells by inhibiting NFkappaB and cooperating with Stat3. Nat Cell Biol 2008; 10:194-201. [PMID: 18223644 DOI: 10.1038/ncb1680] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2007] [Accepted: 12/18/2007] [Indexed: 12/12/2022]
Abstract
Embryonic stem (ES) cells are pluripotent cells derived from the inner cell mass of blastocysts. Self-renewal of mouse ES cells depends on activation of Stat3 by leukaemia inhibitory factor (LIF) in collaboration with bone morphogenetic protein signalling. The transcription factor Nanog is essential in maintaining pluripotency but the mechanisms involved are poorly understood. Here we examine the functional interactions of Nanog with the Stat3 and NFkappaB pathways. Nanog and Stat3 were found to bind to and synergistically activate Stat3-dependent promoters. We also found that Nanog binds to NFkappaB proteins; however, Nanog binding inhibited transcriptional activity of NFkappaB proteins. Endogenous NFkappaB activity and target-gene expression increased during differentiation of ES cells. Overexpression of NFkappaB proteins promoted differentiation, whereas inhibition of NFkappaB signalling, either by genetic ablation of the Ikbkg gene or overexpression of the IkappaBalpha super-repressor, increased expression of pluripotency markers. We conclude that Nanog represses the pro-differentiation activities of NFkappaB and cooperates with Stat3 to maintain pluripotency.
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Affiliation(s)
- Josema Torres
- Wellcome Trust Centre for Stem Cell Research, Tennis Court Road, Cambridge CB2 1QR, UK
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42
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Purbey PK, Singh S, Kumar PP, Mehta S, Ganesh KN, Mitra D, Galande S. PDZ domain-mediated dimerization and homeodomain-directed specificity are required for high-affinity DNA binding by SATB1. Nucleic Acids Res 2008; 36:2107-22. [PMID: 18187506 PMCID: PMC2367706 DOI: 10.1093/nar/gkm1151] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
To better understand DNA recognition and transcription activity by SATB1, the T-lineage-enriched chromatin organizer and transcription factor, we have determined its optimal DNA-binding sequence by random oligonucleotide selection. The consensus SATB1-binding sequence (CSBS) comprises a palindromic sequence in which two identical AT-rich half-sites are arranged as inverted repeats flanking a central cytosine or guanine. Strikingly, the CSBS half-site is identical to the conserved element ‘TAATA’ bound by the known homeodomains (HDs). Furthermore, we show that the high-affinity binding of SATB1 to DNA is dimerization-dependent and the HD also binds in similar fashion. Binding studies using HD-lacking SATB1 and binding target with increased spacer between the two half-sites led us to propose a model for SATB1–DNA complex in which the HDs bind in an antiparallel fashion to the palindromic consensus element via minor groove, bridged by the PDZ-like dimerization domain. CSBS-driven in vivo reporter analysis indicated that SATB1 acts as a repressor upon binding to the CSBS and most of its derivatives and the extent of repression is proportional to SATB1's binding affinity to these sequences. These studies provide mechanistic insights into the mode of DNA binding and its effect on the regulation of transcription by SATB1.
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43
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Bartlett HL, Sutherland L, Kolker SJ, Welp C, Tajchman U, Desmarais V, Weeks DL. Transient early embryonic expression of Nkx2-5 mutations linked to congenital heart defects in human causes heart defects in Xenopus laevis. Dev Dyn 2007; 236:2475-84. [PMID: 17685485 PMCID: PMC2078326 DOI: 10.1002/dvdy.21244] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Nkx2-5 is a homeobox containing transcription factor that is conserved and expressed in organisms that form hearts. Fruit flies lacking the gene (tinman) fail to form a dorsal vessel, mice that are homozygous null for Nkx2-5 form small, deformed hearts, and several human cardiac defects have been linked to dominant mutations in the Nkx2-5 gene. The Xenopus homologs (XNkx2-5) of two truncated forms of Nkx2-5 that have been identified in humans with congenital heart defects were used in the studies reported here. mRNAs encoding these mutations were injected into single cell Xenopus embryos, and heart development was monitored. Our results indicate that the introduction of truncated XNkx2-5 variants leads to three principle developmental defects. The atrial septum and the valve of the atrioventricular canal were both abnormal. In addition, video microscopic timing of heart contraction indicated that embryos injected with either mutant form of XNkx2-5 have conduction defects.
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Affiliation(s)
| | - Lillian Sutherland
- Department of Biochemistry, Bowen Science Building, University of Iowa, Iowa City, Iowa
| | - Sandra J. Kolker
- Department of Biochemistry, Bowen Science Building, University of Iowa, Iowa City, Iowa
| | - Chelsea Welp
- Department of Pediatrics, University of Iowa, Iowa City, Iowa
| | | | - Vera Desmarais
- Department of Biochemistry, Bowen Science Building, University of Iowa, Iowa City, Iowa
| | - Daniel L. Weeks
- Department of Biochemistry, Bowen Science Building, University of Iowa, Iowa City, Iowa
- *Correspondence to: Daniel L. Weeks, Department of Biochemistry, Bowen Science Building, University of Iowa, Iowa City, IA 52242-1109. E-mail:
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44
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Abstract
In this review we discuss the major morphogenetic and regulative events that control myocardial progenitor cells from the time that they delaminate from the epiblast in the primitive streak to their differentiation into cardiomyocytes in the heart tube. During chick and mouse embryogenesis, myocardial progenitor cells go through four specific processes that are sequential but overlapping: specification of the cardiogenic mesoderm, determination of the bilaterally symmetric heart fields, patterning of the heart field, and finally cardiomyocyte differentiation and formation of the heart tube. We describe the morphological and molecular events that play a pivotal role in each of these four processes.
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Affiliation(s)
- Radwan Abu-Issa
- Department of Pediatrics, Neonatal-Perinatal Research Institute, Duke University, Durham, NC 27712, USA.
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45
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Toda A, Okabe M, Yoshida T, Nikaido T. The potential of amniotic membrane/amnion-derived cells for regeneration of various tissues. J Pharmacol Sci 2007; 105:215-28. [PMID: 17986813 DOI: 10.1254/jphs.cr0070034] [Citation(s) in RCA: 205] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Regenerative medicine is a new field based on the use of stem cells to generate biological substitutes and improve tissue functions, restoring damaged tissue with high proliferability and differentiability. It is of interest as a potential alternative to complicated tissue/organ transplantation. Recently, amnion-derived cells have been reported to have multipotent differentiation ability, and these cells have attracted attention as a cell source for cell-transplantation therapy. The amnion possesses considerable advantageous characteristics: the isolated cells can differentiate into all three germ layers; they have low immunogenicity and anti-inflammatory functions; and they do not require the sacrifice of human embryos for their isolation, thus avoiding the current controversies associated with the use of human embryonic stem cells. Moreover, we developed human amniotic cell-sheets using a novel culture surface coated with a noncytotoxic, temperature-responsive elastic protein-based polymer. We also generated a "hyper-dry-amnion", which has already been applied clinically in the ophthalmological field. Compared to cryopreserved fresh amnion, "hyper-dry-amnion" is easy to handle and has started to bring good results to patients. These materials from the amnion are also expected to open a new field in tissue engineering. Thus, amnion, which had been discarded after parturition, has started to be appreciated as an attractive material in the field of regenerative medicine. In this review, the most recent and relevant clinical and experimental data about the use of amniotic membrane and cells derived from it are described.
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Affiliation(s)
- Ayaka Toda
- Department of Regenerative Medicine, University of Toyama Graduate School of Medicine and Pharmaceutical Sciences, 2630 Sugitani, Toyama 930-0194. Japan
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Dixon DN, Izon DJ, Dagger S, Callow MJ, Taplin RH, Kees UR, Greene WK. TLX1/HOX11 transcription factor inhibits differentiation and promotes a non-haemopoietic phenotype in murine bone marrow cells. Br J Haematol 2007; 138:54-67. [PMID: 17555447 DOI: 10.1111/j.1365-2141.2007.06626.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The TLX/HOX11 subfamily of divergent homeobox genes are involved in various aspects of embryogenesis and, in the case of TLX1/HOX11 and TLX3/HOX11L2, feature prominently as oncogenes in human T-cell acute lymphoblastic leukaemia. TLX1 possesses immortalising activity in a wide variety of blood cell lineages, however, the effect of this oncogene on haemopoietic cell differentiation has not been fully investigated. We therefore constitutively expressed TLX1 in murine bone marrow or fetal liver cells using retroviral transfer followed by transplantation and/or in vitro culture. TLX1 was found to dramatically alter haemopoiesis, promoting the emergence of a non-haemopoietic CD45(-) CD31(+) cell population while markedly inhibiting erythroid and granulocytic cell differentiation. To identify genetic programs perturbed by TLX1, a comparison of transcript profiles from J2E erythroid cells with and without enforced TLX1 expression was undertaken. This revealed a pattern of gene expression indicative of enhanced proliferation coupled to differentiation arrest. Of the genes identified, two, KIT and VEGFC, were found to be potential TLX1 targets based on transcriptional assays. These results demonstrate that TLX1 can act broadly to impair haemopoiesis and divert differentiation to an alternative fate. This may account for its ability to promote the pre-leukaemic state via perturbation of specific gene expression programs.
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Affiliation(s)
- Darcelle N Dixon
- School of Veterinary and Biomedical Sciences, Division of Health Sciences, Murdoch University, Murdoch, Western Australia, Australia
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47
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Li T, Li YM, Jia ZQ, Chen P, Ma KT, Zhou CY. Carboxyl Terminus of NKX2.5 Impairs its Interaction with p300. J Mol Biol 2007; 370:976-92. [PMID: 17544441 DOI: 10.1016/j.jmb.2007.05.033] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2007] [Revised: 04/18/2007] [Accepted: 05/14/2007] [Indexed: 11/20/2022]
Abstract
The transcription factor Nkx2.5 plays critical roles in controlling cardiac-specific gene expression. Previous reports demonstrated that Nkx2.5 is only a modest transactivator due to the auto-inhibitory effect of its C-terminal domain. Deletion of the C-terminal domain, mimicking conformational change, evokes vigorous transactivation activity. Here, we show that a C-terminal defective mutant of Nkx2.5 improves the occupation of p300 at the ANF promoter compared with full-length Nkx2.5, leading to hyperacetylation of histone H4. We reveal that p300 is a cofactor of Nkx2.5, markedly potentiating Nkx2.5-dependent transactivation, whereas E1A antigen impairs Nkx2.5 activity. Furthermore, p300 can acetylate Nkx2.5 and display an acetyltransferase-independent mechanism to coactivate Nkx2.5. Physical interaction between the N-terminal activation domain of Nkx2.5 and the C/H3 domain of p300 are identified by GST pull-down assay. Point mutants of the N-terminal modify the transcriptional activity of Nkx2.5 and interaction with p300. Deletion of the C-terminal domain greatly facilitates p300 binding and improves the susceptibility of Nkx2.5 to histone deacetylase inhibitor. These results establish that p300 acts as an Nkx2.5 cofactor and facilitates increased Nkx2.5 activity by relieving the conformational impediment of its inhibitory C-terminal domain.
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Affiliation(s)
- Tao Li
- Department of Biochemistry and Molecular Biology, Peking University Health Science Center, Beijing 100083, China
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Singh AM, Li FQ, Hamazaki T, Kasahara H, Takemaru KI, Terada N. Chibby, an antagonist of the Wnt/beta-catenin pathway, facilitates cardiomyocyte differentiation of murine embryonic stem cells. Circulation 2007; 115:617-26. [PMID: 17261658 PMCID: PMC2565513 DOI: 10.1161/circulationaha.106.642298] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Embryonic stem cell (ESC)-derived cardiomyocytes are anticipated to serve as a useful source for future cell-based cardiovascular disease therapies. Research emphasis is currently focused on determining methods to direct the differentiation of ESCs to a large population of cardiomyocytes with high purity. To this aim, understanding the molecular mechanisms that control ESC-to-cardiomyocyte differentiation should play a critical role in the development of this methodology. The Wnt/beta-catenin signaling pathway has been implicated in both embryonic cardiac development and in vitro ESC differentiation into cardiomyocytes. Chibby is a recently identified nuclear protein that directly binds to beta-catenin and antagonizes its transcriptional activity. METHODS AND RESULTS Chibby was ubiquitously expressed in early stages of ESC differentiation but upregulated during cardiomyocyte specification. Of interest, the Chibby gene promoter has multiple binding sites for the cardiac-specific homeodomain protein Nkx2.5, and its promoter activity was indeed positively regulated by Nkx2.5. Furthermore, overexpression of Chibby increased cardiac differentiation of ESCs, whereas loss of Chibby by RNAi impaired cardiomyocyte differentiation. CONCLUSIONS These data illustrate the regulation and function of Chibby in facilitating cardiomyocyte differentiation from ESCs. By revealing molecular mechanisms that control ESC-to-cardiomyocyte differentiation, this study will allow for the future development of technologies to improve cardiomyocyte differentiation from ESCs.
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Affiliation(s)
- Amar M Singh
- Department of Pathology, University of Florida College of Medicine, Box 100275, Gainesville, FL 32610, USA
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Zaffran S, Reim I, Qian L, Lo PC, Bodmer R, Frasch M. Cardioblast-intrinsic Tinman activity controls proper diversification and differentiation of myocardial cells in Drosophila. Development 2006; 133:4073-83. [PMID: 16987868 DOI: 10.1242/dev.02586] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The NK homeobox gene tinman (tin) is required for the specification of the cardiac, visceral muscle and somatic muscle progenitors in the early dorsal mesoderm of Drosophila. Like its vertebrate counterpart Nkx2.5, the expression of tin is maintained in cardiac cells during cardiac maturation and differentiation; however, owing to the complete lack of a dorsal vessel in tin mutant embryos, the function of tin in these cells has not been defined. Here we show that myocardial cells and dorsal vessels can form even though they lack Tin, and that viable adults can develop, as long as Tin is provided in the embryonic precardiac mesoderm. However, embryos in which tin expression is specifically missing from cardial cells show severe disruptions in the normal diversification of the myocardial cells, and adults exhibit severe defects in cardiac remodeling and function. Our study reveals that the normal expression and activity of Tin in four of the six bilateral cardioblasts within each hemisegment of the heart allows these cells to adopt a cell fate as ;working' myocardium, as opposed to a fate as inflow tract (ostial) cells. This function of tin involves the repression of Dorsocross (Doc) T-box genes and, hence, the restriction of Doc to the Tin-negative cells that will form ostia. We conclude that tin has a crucial role within myocardial cells that is required for the proper diversification, differentiation, and post-embryonic maturation of cardiomyocytes, and we present a pathway involving regulatory interactions among seven-up, midline, tinman and Dorsocross that establishes these developmental events upon myocardial cell specification.
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Affiliation(s)
- Stéphane Zaffran
- Brookdale Department of Molecular, Cell and Developmental Biology, Box 1020, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, NY 10029, USA
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Abstract
Although there have been important advances in diagnostic modalities and therapeutic strategies for congenital heart defects (CHD), these malformations still lead to significant morbidity and mortality in the human population. Over the past 10 years, characterization of the genetic causes of CHD has begun to elucidate some of the molecular causes of these defects. Linkage analysis and candidate-gene approaches have been used to identify gene mutations that are associated with both familial and sporadic cases of CHD. Complementation of the human studies with developmental studies in mouse models provides information for the roles of these genes in normal development as well as indications for disease pathogenesis. Biochemical analysis of these gene mutations has provided further insight into the molecular effects of these genetic mutations. Here we review genetic, developmental, and biochemical studies of six cardiac transcription factors that have been identified as genetic causes for CHD in humans.
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Affiliation(s)
- Krista L Clark
- Division of Cardiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229, USA.
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