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Stennard FA, Harvey RP. T-box transcription factors and their roles in regulatory hierarchies in the developing heart. Development 2006; 132:4897-910. [PMID: 16258075 DOI: 10.1242/dev.02099] [Citation(s) in RCA: 132] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
T-box transcription factors are important players in the molecular circuitry that generates lineage diversity and form in the developing embryo. At least seven family members are expressed in the developing mammalian heart, and the human T-box genes TBX1 and TBX5 are mutated in cardiac congenital anomaly syndromes. Here, we review T-box gene function during mammalian heart development in the light of new insights into heart morphogenesis. We see for the first time how hierarchies of transcriptional activation and repression involving multiple T-box factors play out in three-dimensional space to establish the cardiac progenitors fields, to define their subservient lineages, and to generate heart form and function.
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Affiliation(s)
- Fiona A Stennard
- Victor Chang Cardiac Research Institute, St Vincent's Hospital, 384 Victoria Street, Darlinghurst, New South Wales 2010, Australia
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152
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Harris BS, Spruill L, Edmonson AM, Rackley MS, Benson DW, O’Brien TX, Gourdie RG. Differentiation of cardiac Purkinje fibers requires precise spatiotemporal regulation of Nkx2-5 expression. Dev Dyn 2006; 235:38-49. [PMID: 16245335 PMCID: PMC2610391 DOI: 10.1002/dvdy.20580] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Nkx2-5 gene mutations cause cardiac abnormalities, including deficits of function in the atrioventricular conduction system (AVCS). In the chick, Nkx2-5 is elevated in Purkinje fiber AVCS cells relative to working cardiomyocytes. Here, we show that Nkx2-5 expression rises to a peak as Purkinje fibers progressively differentiate. To disrupt this pattern, we overexpressed Nkx2-5 from embryonic day 10, as Purkinje fibers are recruited within developing chick hearts. Overexpression of Nkx2-5 caused inhibition of slow tonic myosin heavy chain protein (sMHC), a late Purkinje fiber marker but did not affect Cx40 levels. Working cardiomyocytes overexpressing Nkx2-5 in these hearts ectopically up-regulated Cx40 but not sMHC. Isolated embryonic cardiomyocytes overexpressing Nkx2-5 also displayed increased Cx40 and suppressed sMHC. By contrast, overexpression of a human NKX2-5 mutant did not effect these markers in vivo or in vitro, suggesting one possible mechanism for clinical phenotypes. We conclude that a prerequisite for normal Purkinje fiber maturation is precise regulation of Nkx2-5 levels.
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Affiliation(s)
- Brett S. Harris
- Departments of Cell Biology and Anatomy, Medical University of South Carolina, Charleston SC
- Gazes Cardiac Research Institute, Medical University of South Carolina, Charleston SC
| | - Laura Spruill
- Gazes Cardiac Research Institute, Medical University of South Carolina, Charleston SC
| | - Angela M. Edmonson
- Gazes Cardiac Research Institute, Medical University of South Carolina, Charleston SC
- Medical Research Service, Ralph H. Johnson Department of Veteran Affairs Medical Center, Medical University of South Carolina, Charleston SC
| | - Mary S. Rackley
- Gazes Cardiac Research Institute, Medical University of South Carolina, Charleston SC
- Medical Research Service, Ralph H. Johnson Department of Veteran Affairs Medical Center, Medical University of South Carolina, Charleston SC
| | - D. Woodrow Benson
- Department of Molecular and Cardiovascular Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio
| | - Terrence X. O’Brien
- Gazes Cardiac Research Institute, Medical University of South Carolina, Charleston SC
- Medical Research Service, Ralph H. Johnson Department of Veteran Affairs Medical Center, Medical University of South Carolina, Charleston SC
| | - Robert G. Gourdie
- Departments of Cell Biology and Anatomy, Medical University of South Carolina, Charleston SC
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153
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154
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Affiliation(s)
- Jau-Nian Chen
- University of California Los Angeles, Los Angeles, CA, USA
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155
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Hinton RB, Yutzey KE, Benson DW. Congenital heart disease: Genetic causes and developmental insights. PROGRESS IN PEDIATRIC CARDIOLOGY 2005. [DOI: 10.1016/j.ppedcard.2005.04.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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156
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Zhou YQ, Zhu Y, Bishop J, Davidson L, Henkelman RM, Bruneau BG, Foster FS. Abnormal cardiac inflow patterns during postnatal development in a mouse model of Holt-Oram syndrome. Am J Physiol Heart Circ Physiol 2005; 289:H992-H1001. [PMID: 15849237 DOI: 10.1152/ajpheart.00027.2005] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Tbx5(del/+) mice provide a model of human Holt-Oram syndrome. In this study, the cardiac functional phenotypes of this mouse model were investigated with 30-MHz ultrasound by comparing 12 Tbx5(del/+) mice with 12 wild-type littermates at 1, 2, 4, and 8 wk of age. Cardiac dimensions were measured with two-dimensional and M-mode imaging. The flow patterns in the left and right ventricular inflow channels were evaluated with Doppler flow sampling. Compared with wild-type littermates, Tbx5(del/+) mice showed significant changes in the mitral flow pattern, including decreased peak velocity of the left ventricular (LV) early filling wave (E wave), increased peak velocity of the late filling wave (A wave), and decreased or even reversed peak E-to-A ratio. The prolongation of LV isovolumic relaxation time was detected in Tbx5(del/+) neonates as early as 1 wk of age. In Tbx5(del/+) mice, LV wall thickness appeared normal but LV chamber dimension was significantly reduced. LV systolic function did not differ from that in wild-type littermates. In contrast, the Doppler flow spectrum in the enlarged tricuspid orifice of Tbx5(del/+) mice demonstrated increased peak velocities of both E and A waves and increased total time-velocity integral but unchanged peak E/A. In another 13 mice (7 Tbx5(del/+), 6 wild-type) at 2 wk of age, significant correlation was found between Tbx5 gene expression level in ventricular myocardium and LV filling parameters. In conclusion, the LV diastolic function of Tbx5(del/+) mice is significantly deteriorated, whereas the systolic function remains normal.
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MESH Headings
- Animals
- Diastole
- Disease Models, Animal
- Echocardiography
- Female
- Heart/growth & development
- Heart/physiopathology
- Heart Defects, Congenital/diagnostic imaging
- Heart Defects, Congenital/genetics
- Heart Defects, Congenital/physiopathology
- Heart Septal Defects, Atrial/diagnostic imaging
- Heart Septal Defects, Atrial/genetics
- Heart Septal Defects, Atrial/physiopathology
- Male
- Mice
- Mice, Mutant Strains
- Phenotype
- Systole
- T-Box Domain Proteins/genetics
- Ventricular Dysfunction, Left/diagnostic imaging
- Ventricular Dysfunction, Left/genetics
- Ventricular Dysfunction, Left/physiopathology
- Ventricular Dysfunction, Right/diagnostic imaging
- Ventricular Dysfunction, Right/genetics
- Ventricular Dysfunction, Right/physiopathology
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Affiliation(s)
- Yu-Qing Zhou
- Mouse Imaging Centre, Hospital for Sick Children, 555 University Ave., Toronto, ON, Canada M5G 1X8.
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157
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Brown DD, Martz SN, Binder O, Goetz SC, Price BMJ, Smith JC, Conlon FL. Tbx5 and Tbx20 act synergistically to control vertebrate heart morphogenesis. Development 2005; 132:553-63. [PMID: 15634698 PMCID: PMC1635804 DOI: 10.1242/dev.01596] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Members of the T-box family of proteins play a fundamental role in patterning the developing vertebrate heart; however, the precise cellular requirements for any one family member and the mechanism by which individual T-box genes function remains largely unknown. In this study, we have investigated the cellular and molecular relationship between two T-box genes, Tbx5 and Tbx20. We demonstrate that blocking Tbx5 or Tbx20 produces phenotypes that display a high degree of similarity, as judged by overall gross morphology, molecular marker analysis and cardiac physiology, implying that the two genes are required for and have non-redundant functions in early heart development. In addition, we demonstrate that although co-expressed, Tbx5 and Tbx20 are not dependent on the expression of one another, but rather have a synergistic role during early heart development. Consistent with this proposal, we show that TBX5 and TBX20 can physically interact and map the interaction domains, and we show a cellular interaction for the two proteins in cardiac development, thus providing the first evidence for direct interaction between members of the T-box gene family.
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Affiliation(s)
- Daniel D. Brown
- Department of Genetics, Fordham Hall, UNC-Chapel Hill, Chapel Hill, NC 27599-3280, USA
- Department of Biology, Fordham Hall, UNC-Chapel Hill, Chapel Hill, NC 27599-3280, USA
| | - Shauna N. Martz
- Department of Genetics, Fordham Hall, UNC-Chapel Hill, Chapel Hill, NC 27599-3280, USA
| | - Olav Binder
- Department of Genetics, Fordham Hall, UNC-Chapel Hill, Chapel Hill, NC 27599-3280, USA
| | - Sarah C. Goetz
- Department of Genetics, Fordham Hall, UNC-Chapel Hill, Chapel Hill, NC 27599-3280, USA
- Department of Biology, Fordham Hall, UNC-Chapel Hill, Chapel Hill, NC 27599-3280, USA
| | - Brenda M. J. Price
- Wellcome Trust/Cancer Research UK Gurdon Institute of Cancer and Developmental Biology and Department of Zoology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QR, UK
| | - Jim C. Smith
- Wellcome Trust/Cancer Research UK Gurdon Institute of Cancer and Developmental Biology and Department of Zoology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QR, UK
| | - Frank L. Conlon
- Department of Genetics, Fordham Hall, UNC-Chapel Hill, Chapel Hill, NC 27599-3280, USA
- Department of Biology, Fordham Hall, UNC-Chapel Hill, Chapel Hill, NC 27599-3280, USA
- *Author for correspondence (e-mail: )
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158
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Abstract
Members of the T-box gene family (Tbx) are essential for normal heart development, and mutations in human TBX genes cause congenital cardiovascular malformations. T-box genes have been implicated in early cardiac lineage determination, chamber specification, valvuloseptal development, and diversification of the specialized conduction system in vertebrate embryos. These genes include Tbx1, Tbx2, Tbx3, Tbx5, Tbx18, and Tbx20, all of which exhibit complex temporal spatial regulation in developing cardiac structures. Less is known about T-box genes in invertebrate heart development, but multiple T-box genes are expressed in Drosophila cardiac lineages. The molecular hierarchies and developmental processes controlled by T-box genes in the heart are the focus of this review.
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Affiliation(s)
- Timothy F Plageman
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, ML7020, Cincinnati, Ohio 45229, USA
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