Figure 9

The genetic network that leads to cardiac apoptosis in raw mutation. At stage 14, Raw restricts bsk which limits the expression of dpp at ectodermal leading edge cells. Minimal Dpp activity maintains the activation of cardiogenic factors which are essential for the differentiation of cardial cells. In raw mutation, Bsk is de-regulated which causes overexpression of dpp in dorsal ectoderm at stage 14. Ectopic dpp signaling increases the expression of cardiogenic factors which results in overgrowth of cardial cell types at stage 14. At stage 15, while the expression of Dpp in the LE cells gradually decreases, heart cells are continuously differentiated with the function of cardiogenic factors. At stage 15, DTAK1 is activated by the ectopic Dpp signaling in raw mutant. DTAK1 activates DJNK and thereby Dpp. Autocrine Dpp further enhances DJNK and eventually leads to P53-dependent apoptosis.