Fig. 8. hbs expression depends on sim, Notch and bap, but not mef2. (A) Wild-type stage 11 embryo showing characteristic line (arrowhead) of hbs expression in the mesectoderm. (B,C) This expression is absent in the sim mutant embryo (B, arrowhead), and expanded in UAS-sim/sca-GAL4 embryos (C, arrowhead). (D) In a stage 12 Notch embryo, hbs expression is absent at the CNS midline (arrowhead; compare with Fig. 3F). (E,F) Stage 11 mef2 embryos show normal expression of hbs in visceral mesoderm cells (E, arrowhead), but this is greatly reduced in bap mutant embryos (F, arrowhead).