Fig. 1. Upstream regions of Gyc-89Da and Gyc-89Db drive green fluorescent protein (GFP) expression in sensory neurons in larvae in a similar pattern to that seen with in situ hybridization for Gyc-89Da and Gyc-89Db in embryos. Second instar larvae containing the p89Da-GFP (B,E,H,K) or p89Db-GFP (C,F,I,L) transgenes were examined for GFP fluorescence and compared with embryos stained with a digoxigenin-labeled riboprobe for Gyc-89Db (A,D,G,J). Anterior is to the left (A–C) or up (D–L). (A–C) Low magnification showing the three populations of sensory neurons stained: chemosensory neurons in the dorsal ganglion (DG) and terminal ganglion (TG), external sensilla (ES) neurons and neurons in the terminal sensory organs (SO). (D–F) High magnification of the lateral body wall showing a neuron innervating the external sensilla. (G–I) High magnification of the anterior end of embryo or larvae showing neurons in the dorsal ganglion and terminal ganglion that innervate the dorsal organ (DO) and terminal organ, respectively. p89Db-GFP also drives GFP expression in neurons in the monoscolopidial organ (mc). (J–L) High magnification of the posterior end of embryo or larvae showing a single neuron innervating each terminal sensory organ. Fluorescence seen in tracheae is due to autofluorescence. Scale bars represent 200 µm (A), 500 µm (B,C), 50 µm (D,G,J) and 100 µm (E,F,H,I,K,L).