Description
During gastrulation, cells of the prospective mesoderm ingress through the primitive streak and acquire fates based on complex spatial and temporal cues. Progenitors of the cardiogenic mesoderm are first found at E6.5 in the posterior lateral epiblast and subsequently migrate laterally and anteriorly to form the cardiac crescent at E7.5, when regionalized cell fates are first delineated . Lineage tracing and heterotopic transplantation studies suggest that precursors in the earliest heart field possess potential to generate myocardium, endocardium, and pericardium. The mechanisms by which inductive signals in the primitive streak effect the development of this pancardiac progenitor field, however, remain poorly understood