Induction of MesP1 by Brachyury(T) generates the common multipotent cardiovascular stem cell

Aims Our recent work demonstrated that common cardiovascular progenitor cells are characterized and induced by the expression of the transcription factor mesoderm posterior1 (MesP1) in vertebrate embryos and murine embryonic stem cells. As the proliferative potential of stem cell-derived cardiomyocytes is limited, it is crucial to understand how MesP1 expression is mediated in order to achieve reasonable and reliable yields for novel stem cell-based therapeutic options. As potential upstream regulators of MesP1, we therefore analysed Eomes and Brachyury(T), which had been controversially discussed as being crucial for cardiovasculogenic lineage formation. Methods and results Wild-type and transgenic murine embryonic stem cell lines, mRNA analyses, embryoid body formation, and cell sorting revealed that the MesP1 positive population emerges from the Brachyury(T) positive fraction. In situ hybrid-izations using wild-type mouse embryos confirmed that Brachyury(T) colocalises with MesP1 in vivo. Likewise, shRNA-based loss of Brachyury(T) causes a dramatic decrease in MesP1 expression accompanied by reduce