Netrins control guidance of CNS commissural axons and peripheral motor axons (PubMed:8780645, PubMed:8780646, PubMed:11719202). Its association with either fra or unc-5 receptors will lead to axon attraction or repulsion, respectively (PubMed:11719202). While short-range repulsion requires both fra and unc-5 receptors, long-range repulsion only requires unc-5 (PubMed:11719202). Binds to unc-5 and fra receptors. Expressed in the perinuclear region of the oldest most anterior lamina neurons at 24 hours after puparium formation. At 24 hr after puparium formation (APF), detected in the most anterior (oldest) L3, L4 and L5 lamina neurons (at protein level) (PubMed:29513217). At 48 hr APF, expressed in all L3, L4 and L5 neurons with slightly higher expression in the L3 neurons (at protein level) (PubMed:29513217). At the midline of developing CNS and in different subsets of neurons, muscles, and epidermal patches (PubMed:8780645, PubMed:8780646). It is uncertain whether Met-1 or Met-9 is the initiator.