N-terminal deletion removing sequences encoding the first 98 amino acids of comm.
Pan-neural expression of one copy of commΔ2.Scer\UAS.T:Avic\GFP-m6 under the control of Scer\GAL4unspecified has little effect on axon outgrowth in the embryonic central nervous system, while pan-neural expression of two copies of commΔ2.Scer\UAS.T:Avic\GFP-m6 under the control of Scer\GAL4unspecified results in a robo phenocopy.