The developing Heart

COVER Immunofluorescence microscopy identifies an intermediate cell in the cardiomyocyte lineage. An image of the heart of a 14.5-day mouse embryo shows this intermediate—progenitor derivatives expressing Hopx (red)—and the differentiated myocytes expressing troponin (green). Jain et al. demonstrate that Hopx-expressing cells promote cardiomyocyte commitment by coordinating signaling pathways in the progenitor niche. See page 1444 and dx.doi.org/10.1126/science.aaa6071.
Image: Epstein laboratory