C17E4.3::GFP reporter expression. Present in the head and tail regions of larval stages. Panel Ai shows an overview of an L1 animal, with distinct cells near the anterior pharyngeal bulb as well as in the tail. Close up of the head reveals GFP expressing cells (Panel Bii), including muscle cells located in the posterior pharyngeal bulb (Panel Biv, labeled 'p'). Sheath/socket cells located at the anterior pharyngeal bulb are indicated in panels Biv, Dii and Diii. Dye-filling tests (see Materials and Methods) to stain sensory amphid (head) and phasmid (tail) neurons are shown in panels C and D. The amphids are specifically visualized in panel Civ (red fluorescence), and under an FITC filter in Ciii (yellow fluorescence, not in nucleus) and green with an EGFP filter, and are not the same as the cells expressing the C17E4.3::GFP reporter (arrow in panels Cii and Ciii). In the tail, phasmids (labeled 'ph') are clearly seen in panel Div just below the anus (cl), but are not expressing GFP, which is instead present in several hypodermal cells (arrow panel Diii). Scale bar represent 10 μm.