Defining the earliest step of cardiovascular lineage segregation by single-cell RNA-seq

Committing the heart The heart is a complex organ composed of multiple cell types such as cardiomyocytes and endothelial cells. Cardiovascular cells arise from Mesp1 -expressing progenitor cells. Lescroart et al. performed single-cell RNA-sequencing analysis of mouse wild-type and Mesp1 -deficient cardiovascular progenitor cells at early gastrulation (see the Perspective by Kelly and Sperling). When Mesp1 was eliminated, embryonic cells remained pluripotent and could not differentiate into cardiovascular progenitors. During gastrulation, the different Mesp1 progenitors rapidly became committed to a particular cell fate and heart region. Notch1 expression marked the earliest step of cardiovascular lineage segregation. Science , this issue p. 1177 ; see also p. 1098