Figure 5.

spineless regulates the number of dendritic spikes in the class III neurons. (A) Normal morphology of lateral class III neuron ldaB dendrites in a wild-type MARCM clone. Dendritic spikes are found along all major branches. (B,C) ldaB neurons show a reduction of dendritic spikes along all major branches in ss¹³⁴ (B) and ss^D115.7 (C) MARCM clones. (D) Normal morphology of dorsal class III neuron ddaF dendrites in a wild-type MARCM clone. ddaF extends long primary and secondary dendrites that are decorated with dendritic spikes. (E,F) ddaF neurons show a reduction in the number of dendritic spikes and exhibit clusters of longer terminal branches along the primary dendrites in ss¹³⁴ (E) and ss^D115.7 (F) MARCM clones. Arrowheads indicate axons. (G) Quantification of total number of branchpoints for ldaB in wild-type and ss^D115.7 clones (asterisk; p < 0.001, two-tailed t-test). (H) Quantification of total number of branchpoints for ddaF indicates no significant difference between wild-type and ss^D115.7 clones. (I,J) Tracing of representative ldaB axon terminals in wild-type (I) and ss^D115.7 (J) MARCM clones. ldaB axons always terminate between the intermediate and medial fascicles in wild-type (I) and ss^D115.7 (J) MARCM clones. (K,L) Tracing of representative ddaF axon terminals in wild-type (K) and ss^D115.7 (L) MARCM clones. ddaF axons project into the VNC and curve posteriorly between the intermediate and medial fascicles in wild-type (K) and ss^D115.7 (L) MARCM clones. Bar, 50 μm.