Imp7 homozygous mutant MARCM mushroom body γ neuron clones in adults have an increased number of neurons that fail to elongate properly, compared to controls.
In contrast to wild type, about 50% of single Imp7 γ axons (generated via MARCM) fail to reach the end of the medial lobe in the adult. These defects do not result from axon retraction, and mutant axons of normal length but lost directionality are observed. Mutant neurons also exhibit an overall decrease in the complexity of axonal arborization patterns, characterized by a reduced number of terminal branches.
Both single larval γ neurons and single adult α'β' neurons mutant for Imp7 project their axons normally, and larval γ neuron neuroblast clones exhibit a normal morphology - the Imp7 neuronal phenotype is restricted to adult γ axons.