Netrin was first discovered in a biochemical assay for the attraction of vertebral commissural axons to floor plate. In mutants for the worm netrin homologue Unc6, sensory axons failed to project ventrally and motor neurons fail to project dorsally. This result suggested that:
A) Unc6 can repel neurons as well as attract them.
B) Unc6 and netrin have conserved roles as well as sequences.
C) sensory neurons and motor neurons somehow interpret the Unc6 signal differently.
D) All of the above
E) None of the above

Question

Quizplus · Accepted Answer

The mutant axons behave in opposite ways to the same source of netrin. They must interpret the signal differently to be attracted in one case and repulsed in the other. Also, Unc6 apparently can function as an axon guidance cue in both worms and vertebrates.

Netrin Was First Discovered in a Biochemical Assay for the Attraction