Larval A-motor neuron enriched transcripts are revealed by mRNAtagging with unc-4::3XFLAG::PAB-1. (a) Antibody staining detects FLAG::PAB-1 expression in A-class neurons in the retrovesicular ganglion (RVG), ventral nerve cord (VNC), and pre-anal ganglion (PAG) and in the I5 pharyngeal neuron (arrowhead). Lateral view of L2 larva, anterior is to left, ventral down. (b) Close-up of posterior ventral nerve cord (boxed area in (a)) showing that anti-FLAG staining (red) is restricted to cytoplasm of A-class motor neurons. DAPI (blue) marks cell nuclei (compare to Figure 1, in which all motor neurons show anti-FLAG staining). Anterior is left, ventral is down. Scale bars = 10 μm. (c) Results of a single larval A-class hybridization (47-DMM3; red) compared to average reference intensities (green) to identify differentially expressed transcripts. The known A-class genes unc-4 (homeodomain, A-class neurons), unc-3 (O/E transcription factor, cholinergic VNC motor neurons), and unc-17 (VAChT, cholinergic neurons) are enriched (red) in 47-DMM3. Genes expressed in other classes of neurons (unc-25, GAD, GABAergic neurons) or other tissues (myo-2, pharyngeal muscle myosin; unc-22, body wall muscle structural protein) are depleted (green) relative to the reference profile.