The expression of Ube3a^UAS.cRa under the control of Scer\GAL4^repo, but not Scer\GAL4^elav.PU, leads to adults showing progressive (age-dependent) bang-induced paralysis, as well as heat-induced and photogenic paralyses. These adults show altered morphology of the mushroom body (namely misdirected lobes) and of the optic lobes, as compared to controls; these defects do not seem to be due to any obvious neuronal loss (assessed by Elav protein levels in head extracts), as compared to controls.

Expression under the control of Scer\GAL4^repo, but not Scer\GAL4^elav.PU, also leads significant decreases in the amplitudes of On transients, Off transients and photoreceptor potential in electroretinograms, despite no obvious defects in ommatidial structure (i.e. photoreceptor neurons are stereotypically arranged and secondary pigment glial cells are present and directly contact photoreceptor neurons), as compared to controls.

Flies with Ube3a^UAS.cRa driven by Scer\GAL4^GMR.PU have a rough eye phenotype; the severity depends on the insertion line used.

At the neuromuscular junction, stimulations at 15Hz intermittently fail to evoke excitatory junction potentials (EJPs) in third instar larvae with over-expression of Ube3a^UAS.cRa driven by Scer\GAL4^elav-C155; depending on the insertion line used, this can be significantly more failures than in controls. There are no significant differences in EJP amplitude over the course of 30 stimulations at 15Hz in larvae that do not exhibit failures. There is no significant difference between controls and Ube3a^UAS.cRa (P{UAS-Ube3a.R}27 insertion line) in mEJP amplitude or frequency in the presence of tetrodotoxin (TTX).

There is no significant difference in active zone density, bouton numbers or synaptic vesicle number at the neuromuscular junction of third instar larvae with Ube3a^UAS.cRa (P{UAS-Ube3a.R}27 insertion line) driven by Scer\GAL4^elav-C155, compared to wild type. There are significantly fewer active zones at the neuromuscular junctions of third instar larvae with Ube3a^UAS.cRa (P{UAS-Ube3a.R}27 insertion line) driven by Scer\GAL4^elav-C155 (though these numbers could be artificially inflated).