In nabSH143 embryos, thoracic neuroblast 3-3 (NB3-3T) shows delayed quiescence and prolonged proliferation. (This is also true of many other thoracic neuroblasts in mutant first instar larvae.) Consequently, NB3-3T generates additional EL neurons.
Most larvae homozygous for nabSH143 die as first instar larvae. Marker analysis indicates that Tv neurons are absent from nabSH143 homozygous first instar larvae.