Cardiopharyngeal Progenitor Specification: Multiple Roads to the Heart and Head Muscles

During embryonic development, the heartarise from various sourcesof undifferentiated mesodermal progenitors, with an additional contribution from ectodermal neural crest cells. Mesodermal cardiac progenitorsareplasticand multipotent,but are nevertheless specified to a precise heart region and cell type very early during development. Recent findings have defined both this lineage plasticity and early commitment of cardiac progenitors, using a combination of single-cell and population analyses. In this review, we discuss several aspects of cardiac progenitor specification. We discuss their markers, fate potential in vitroand in vivo, early segregation and commitment, and also intrinsic and extrinsic cues regulatinglineage restrictionfrom multipotency to a specific cell type of the heart. Finally, we also discuss the sub-divisionsof the cardiopharyngeal field, and the shared origins of the heart with other mesodermal derivatives, including head and neck muscles.