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

Abstract

Mouse heart development arises from Mesp1 expressing cardiovascular progenitors (CPs) that are specified during gastrulation. The molecular processes that control early regional and lineage segregation of CPs remain unclear. Here, we performed single cell RNA-sequencing of WT and Mesp1 null CPs. We showed that Mesp1 CPs are molecularly distinct and make the continuum between epiblast and later mesodermal cells including hematopoietic progenitors. Single cell transcriptome analysis of Mesp1 deficient CPs showed that Mesp1 is required for the exit from the pluripotent state and the induction of the cardiovascular gene expression program. We identified distinct populations of Mesp1 CPs that correspond to progenitors committed to different cell lineages and regions of the heart, identifying the molecular features associated with early lineage restriction and regional segregation of the heart at the early stage of gastrulation.