fafEP381 overexpression mutants exhibit defects in the giant fiber-tergotrochanteral motorneuron synapse, such as axonal overgrowth.
Neural expression of fafEP381, under the control of Scer\GAL4elav-C155 leads to an increased number of synaptic boutons and branches and an increased synaptic span.
Expression of fafEP381 under the control of Scer\GAL4GMR.PF at room temperature results in smooth glassy eyes (due to fusion of ommatidia) that are also moderately reduced in size.
Flies expressing fafEP381 under the control of Scer\GAL4ap-md544 have ectopic bristles on the dorsal surface of the wing blade.
When fafEP381 is driven by Scer\GAL4elav-C155, a marked expansion in the size and complexity is seen in the synapses. There is an increase in both the number of synaptic boutons and in the synaptic span. There is also an increase in the number of synaptic branches. When the evoked excitatory junctional potentials (EJPs) of fafEP381, Scer\GAL4elav-C155 embryos are examined, a marked reduction is seen in their amplitudes. A large decrease in quantal content is also seen, and the frequency of spontaneous mEJPs is also reduced.
Mutant larvae expressing fafEP381 under the control of Scer\GAL4elav-C155 have ISN neuron pathfinding defects. Mutant larvae expressing fafEP381 under the control of Scer\GAL4elav-C155 have excessive or ectopic synapses. Mutant larvae expressing fafEP381 under the control of Scer\GAL4elav-C155 have reduced or abnormal synapses. They have abnormal ISN synaptic branches and a reduced number of boutons.
In the dorsal muscle region of mutant larvae expressing fafEP381 under the control of Scer\GAL4elav-C155, the synapses at the second branchpoint and terminal arbor have abnormal structures, with a spray of extra branches emanating from the terminal arbor.
Expression of fafEP381 under the control of Scer\GAL4sca-537.4 results in loss of external support cells of the scutellar and dorsocentral macrochaetae without loss of the sheath cell. Shafts with a branched tip are seen. On the abdomen, dot-like shaft morphology is seen.