In pros^JO13 mutants, there is a reduction in the number of neurons that differentiate to express exex, despite the increase in proliferation in these mutants.

Mutant embryos show an increase in longitudinal glia (LG) number prior to neuronal contact and a reduction in LG number and LG mitosis after neuronal contact. The final number of LG cells per hemisegment is 8, instead of the normal 10-12.

An increased number of apoptotic cells are seen in the ventral nerve cord of homozygous stage 16 homozygous embryos compared to wild type.

Defects in dentritic misrouting are seen in embryos. No obvious cell change is seen in the PNS, but abnormal outgrowth and misrouting of axons from dorsal clusters of sensory neurons. These sorts of phenotype are seen about 10% of embryos.

Mutant phenotype of lateral chordotonal axons includes: shorter axons or dorsally routed axons.

No outgrowth of motorneuron axons along either the segmental or intersegmental nerve track occurs up to 1.5 hours after they would have exited the CNS in a wild type embryo. Axons from all four clusters of sensory neurons are misrouted. Total number of sensory neurons is normal. The specializations at the tips of the dendrites of neurons with single dendrites is normal in both number and location.