Fig. 6. Poxn expression in the embryonic and adult CNS. (A-C) Poxn expression in the developing embryonic ventral cord. (A) Segmentally repeated expression of Poxn protein in the CNS of a stage 15 w; Poxn^M22-B5 embryo rescued by C1-1-86, shown as ventral view under Nomarski optics at a resolution of 20x magnification. The Poxn protein is detected by a rabbit anti-Poxn antiserum. (B,C) GFP expression in the ventral CNS of a w; Poxn-Gal4-13-1 UAS-GFP embryo at stage 17, visualized in a ventrolateral overview (B) or enlarged view (C) by confocal fluorescence microscopy at a resolution of 20x magnification and with maximum projection of Z-stack. (B) Clusters of segmentally repeated GFP expressing neurons in thorax (T1-T3) and abdomen (A1-A8) of the ventral CNS and projections from the ventral and lateral pes organs of the thoracic (t1-t3) and first four abdominal segments (a1-a4) into the ventral cord are clearly visible. (C) The morphology of the cell bodies and projections demonstrate that most, if not all, of the GFP-expressing cells in the ventral cord are neurons. The ventral midline is indicated by a white line. Note that this pattern of Poxn expression, which normally disappears by stage 17, is still clearly visible because of the high stability of Gal4 and GFP. (D,E) Poxn expression in the adult ventral ganglion. Ventral views of the anterior part of a thoracic ganglion dissected from a w; Poxn-Gal4-14-1 UAS-GFP male (D) or female (E) adult. Projections of the chemosensory neurons of the gustatory bristles on legs and wings are labeled by Poxn-driven GFP expression and visualized by confocal fluorescence microscopy, as in B. Note that in females, no projections from the prothoracic chemosensory neurons are crossing the midline. pro ln, prothoracic leg neuromere, wn, wing neuromere, mes ln, mesothoracic leg neuromere. Anterior is towards the left (A,B) or upwards (C-E).