Cardiovascular Research Center, Massachusetts General Hospital, Boston, MA 02114, USA. smwu@partners.org
Stem cell-based cardiac regeneration requires a detailed understanding of the factors that induce cardiac lineage commitment. In this issue of Cell Stem Cell, Lindsley et al. (2008) and Bondue et al. (2008) use embryonic stem cells to identify a key role for Mesp1 in this process.