Fig. 3. Brain defects resulting from removal of mesoderm. Staining as described for Fig. 2. All embryos at ES15. (A,B) Dorsal and lateral views, respectively, of tinman (tin) mutant embryos. b1 shows a thinning of the preoral brain commissure (arrow) and abnormal closeness of the brain hemispheres (arrowhead). (C,D) Dorsal and lateral views, respectively, of embryos in which the mesoderm was ablated using a pan-mesodermal GAL4 driver to express Ricin toxin. These embryos also show a thinning of the preoral brain commissure (arrow) and a fusion of the brain hemispheres at the dorsal midline (arrowhead). In addition, these embryos lack the frontal commissure and ganglion.
