Atrioventricular valve development commences with an EMT event whereby endocardial
cells transform into mesenchyme. The molecular events that induce this phenotypic change
are well understood and include many growth factors, signaling components, and
transcription factors. Besides their clear importance in valve development, the role of these
transformed mesenchyme and the function they serve in the developing prevalve leaflets is
less understood. Indeed, we know that these cells migrate, but how and why do they …