GATA4 Is Essential for Formation of the Proepicardium and Regulates Cardiogenesis

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 101; no. 34; pp. 12573 - 12578
• Main Authors: Watt, Alistair J., Battle, Michele A., Li, Jixuan, Duncan, Stephen A., Olson, Eric N.
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 24.08.2004; National Acad Sciences
• Subjects: Animals; Biological Sciences; Biology; Cell lines; Defects; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Embryo, Mammalian - anatomy & histology; Embryo, Mammalian - physiology; Embryonic Structures - anatomy & histology; Embryonic Structures - physiology; Embryos; Endocardium; Endoderm; Endothelial cells; GATA4 Transcription Factor; Gene expression; Genetic Complementation Test; Heart; Heart - anatomy & histology; Heart - embryology; Heart Defects, Congenital; Mice; Mice, Knockout; Morphogenesis - physiology; Myocardium; Myocardium - cytology; Myocardium - metabolism; Myocardium - pathology; Pericardium - anatomy & histology; Pericardium - embryology; Sinuses; Stem cells; Stem Cells - physiology; Tetraploidy; Transcription Factors - genetics; Transcription Factors - metabolism
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.0400752101

The role of GATA4 during the earliest stages of cardiogenesis has not been defined because Gata4 knockout embryos suffer an early developmental arrest caused by deficiencies in extraembryonic visceral endoderm function. We have used tetraploid embryo complementation to rescue these defects and generated clonal embryonic day 9.5 Gata4-/-embryos directly from embryonic stem cells. GATA4-null embryos display heart defects characterized by disrupted looping morphogenesis, septation, and a hypoplastic ventricular myocardium. We find that myocardial gene expression is relatively normal in GATA4-null hearts including expression of GATA6. Moreover, GATA4 expression in the endocardium is dispensable for trabeculae formation. Remarkably, the proepicardium is absent in GATA4-null embryos, blocking formation of the epicardium. Therefore, we propose that the observed myocardial defects may be a secondary consequence of loss of the proepicardium. These findings definitively demonstrate a requirement for GATA4 during early cardiac development and identify an essential factor for generation of the proepicardium.