Fig. 6. Examination of pan-neuronal cell fate in ttx-3 mutants. (A) Expression of three pan-neuronal markers, unc-119::gfp (otIs45), unc-33::gfp (otEx75) and F25B3.3::gfp (evIs111), in wild-type L1 larvae (see also Materials and Methods). (B) F25B3.3::GFP is expressed in postmitotic neurons. Three evIs111 embryos are shown in a fluorescence micrograph (left panel) and a corresponding DIC micrograph (right panel); the embryos are at the threefold stage (>500 minutes; upper left), the 1.5-fold stage (>400 minutes; upper right) and approximately the 350 minute stage (lower right). Most embryonically generated neurons have been born by the 350 minute stage (Sulston et al., 1983). (C) Expression of pan-neuronal markers in ttx-3(mg158) animals. Fluorescence micrographs and the corresponding DIC images are shown side by side. The three white arrows point to the characteristic row of three neurons behind the excretory cell, AIM, AIY and AVK. Animals are late larvae/young adults. 100% ttx-3(mg158); evIs111 animals showed expression in AIY (n=25; large white arrow). Expression of otIs45 and otEx75 is mosaic in wild-type animals. 90% of otIs45 animals show gfp expression in AIY (n=39); in ttx-3(mg158);otIs45, 88% of animals show gfp expression in AIY (n=48). In otEx75, 62% of animals show expression in AIY (n=24); in ttx-3(mg158); otEx75, 53% of animals show expression in AIY (n=28).