Figure 1. UNC-4:: GFP is expressed in four classes of ventral cord motor neurons (DA, VA, VC, and SAB). The
unc-4 promoter was fused to GFP for expression in transgenic animals (Pflugrad et al., 1997). A, Left lateral view showing a representative VA motor neuron with anteriorly directed axon in the VNC and a DA motor neuron with circumferential commissure and anteriorly directed axon in the dorsal nerve cord.B, Ventral view of L1 larva showing GFP accumulation in cell bodies of all nine DA motor neurons and in two SAB motor neurons (arrowheads). Axons are out of the plane of focus.C, Left lateral view of L2 larva showing GFP expression in all 12 VA motor neuron cell bodies. D, E, Ventral view of adult hermaphrodite showing GFP-positive VC4 and VC5 somata and VC1-VC6 axonal projections to vulval muscles (arrowhead). F, Left lateral view of GFP expression in anteriorly directed axonal projections (arrows) of SAB motor neurons. (Only two of four SAB processes are shown.) AVF processes in the nerve ring (arrowhead) and the I5 motor neuron (asterisk) in the posterior bulb of the pharynx also show UNC-4:: GFP expression. G, Three SAB motor neurons innervating ventral (SABVL, SABVR) and dorsal (SABD) muscles in the head. Images shown in D andF are flattened stacks of optical sections collected in the confocal microscope. Scale bars, 10 μm. Anterior is to the left.