– Altered expression of Htl disrupts pSc neuron synaptic connectivity. a-d Htl mutants have a higher frequency of synaptic targeting errors. Representative examples of wildtype pSc axonal arbors (a), Htl RNAi (b), Htl Dominant Negative (c) and Htl overexpression (d). e Overexpression of Htl with the Htl DN in the pSc neuron reverted the axonal branching pattern to wildtype. f Htl mutants had stereotyped pSc axonal targeting errors, similar to Btl mutants. Red indicates reduction of branches, green indicates ectopic branches. Quantitative analysis showed a significant decrease in the total branch length (g) and total number of branches (h) in Htl RNAi compared to control arbors. In contrast, Htl overexpression within the pSc neuron resulted in a higher occurrence of axonal branch misrouting and ectopic branches, but also missing core branches (f). Overall, Htl overexpression resulted in a significant increase in total branch length (g) and total number of branches (h) compared to control. Scale bar is 50 μm. Arrowheads point to absent branches, arrows point to ectopic branches. Error bars are S.D.