Utilizing Zebrafish to Understand Second Heart Field Development

Heart formation relies on two sources of cardiomyocytes: the first heart field (FHF), which gives rise to the linear heart tube, and the second heart field (SHF), which gives rise to the right ventricle, the outflow tract, parts of the atria, and the inflow tract. The development of the SHF is of particular importance due to its relevance to common congenital heart defects. However, it remains unclear how the SHF is maintained in a progenitor state while the FHF differentiates. Likewise, the factors that trigger SHF differentiation into specific cardiac cell types are poorly understood. Investigation of SHF development can benefit from the utilization of multiple model organisms. Here, we review the experiments that have identified the SHF in zebrafish and investigated its contribution to the poles of the zebrafish heart. Already, zebrafish research has illuminated novel positive and negative regulators of SHF development, cementing the utility of zebrafish in this context.