Different Requirements for GATA Factors in Cardiogenesis Are Mediated by Non-Canonical Wnt Signaling

GATA factors and Wnt signals are key regulators of vertebrate cardiogenesis, but specific roles for individual GATA factors and how they interact with Wnt signaling remain unknown. We use loss of function and overexpression approaches to elucidate how these molecules regulate early cardiogenesis in Xenopus. In order to minimize indirect effects due to abnormal early embryogenesis, we use pluripotent embryonic tissues as cardiogenic assays. We confirm central roles for GATA4, 5, and 6 in cardiogenesis, but also discover individual and different requirements. We show that GATA4 or 6 regulate both cardiogenic potential and subsequent cardiomyocyte differentiation but that GATA5 is involved in regulating cardiomyocyte differentiation. We also show that Wnt11b signaling can rescue reduced cardiac differentiation resulting from loss of function of GATA4 and 6 but not GATA5. We conclude that Wnt11b mediates the differential requirements for GATA factors during vertebrate cardiogenesis. Developmental Dynamics 240:649-662, 2011. (C) 2011 Wiley-Liss, Inc.