CG11966GS-A304; Scer\GAL4sca-4512 embryos exhibit dramatic fusion of ventral nerve cord commissures and collapse of the ventral nerve cord. Marker analyses show reduction and disorganisation of various ventral midline cells types and increased ventral nerv cord cell death. The overall morphology of the post stage 13 CG11966GS-A304; Scer\GAL4sca-4512 embryos is quite distorted. Loss of epidermal tissues occurs on the ventral side of these embryos from stage 13 and continues until, by stage 17, only a small patch of cuticle on the dorsal side of the embryo remains. CG11966GS-A304; Scer\GAL4sim.PS embryos have no obvious epidermal phenotypes and show only a mild fused commissure phenotype in the ventral nerve cord. CG11966GS-A304; Scer\GAL4GMR.PF flies have a severe reduction in eye size. CG11966GS-A304; Scer\GAL4elav-C155 embryos have no obvious phenotype.