Connecting heart and head muscle development in a DiGeorge syndrome mouse model

Abstract

Cardiac and craniofacial congenital defects are among the most prevalent congenital anomalies. New data has revealed a link between heart and head muscle development in the early embryo. Cardiopharyngeal mesoderm associated with the developing foregut or pharynx contains common heart and head muscle progenitor cells and perturbation of this developmental field results in a spectrum of cardiac and craniofacial congenital anomalies, typified by DiGeorge or 22q11.2 deletion syndrome. These include the most common forms of congenital heart defects, reflecting the critical role of addition of second heart field progenitor cells to growth of the embryonic heart. The transcription factor TBX1 is the major gene implicated in DiGeorge syndrome and regulates both cardiac and skeletal myogenic derivatives of pharyngeal mesoderm. Here the epithelial properties of pharyngeal mesoderm will be discussed, as well as Tbx1 function in segregating cardiac progenitor cells to the arterial and venous poles of the heart from a common progenitor pool in posterior pharyngeal mesoderm that additionally contributes to skeletal muscles.