In wild-type animals (upper panel), UNC-6/netrin signaling directs PVQ axon extension ventrally to the midline, where a local guidance cue, probably produced by the preanal ganglion, promotes anterior turning of the PVQ growth cone. In follower lumbar neurons, DGN-1 acts to block premature response to the preanal ganglion cue, allowing the follower axons to track along the PVQ pioneer through an adhesive or short-range attractive interaction. In the absence of DGN-1 (lower panel), follower lumbar axons polarize obliquely toward the preanal ganglion cue rather than tracking along PVQ. DGN-1 similarly blocks abnormal response of the PLM axon to the same attractive preanal ganglion signal, allowing it to maintain a lateral position.