Figure 1. Patronin is required for dendrite pruning in ddaC neurons.

(A) A schematic representation of dendrite pruning in ddaC neurons. (B–F) Live confocal images of ddaC neurons expressing mCD8-GFP driven by ppk-Gal4 at WP and 16 hr APF. While the wild-type neurons pruned all the dendrites (B), ddaC neurons overexpressing patronin RNAi #1 (C), patronin^c9-c5 (D) or patronin^k07433 (F) MARCM ddaC clones exhibited simple arbors at WP stage and dendrite pruning defects at 16 hr APF. Low-level expression of mCherry-Patronin under the control of the UASp promoter fully restored the elaborate arbors at WP and rescued the pruning defects at 16 hr APF in patronin^c9-c5 MARCM ddaC clones (E). Red arrowheads point to the ddaC somas. (G) Quantification of total length of unpruned ddaC dendrites at 16 hr APF. (H) Quantification of severing defects at 16 hr APF. Scale bar in (B) represents 50 μm. Error bars represent SEM. The number of samples (n) in each group is shown on the bars. ***p<0.001 as assessed by two-tailed Student’s T test.

Figure 1—figure supplement 1. Patronin is required for dendrite pruning and arborization in sensory neurons.

(A–E) Live confocal images of da neurons expressing mCD8-GFP at w3L, WP, 16 hr and 20 hr, 32 hr APF. (A) While the control neurons pruned all the dendrites at 16 hr APF, ddaC neurons overexpressing patronin RNAi #2 or patronin RNAi #3 by ppk-Gal4 exhibited dendrite pruning defects at 16 hr APF. Red arrowheads point to the ddaC somas. Quantification of the severing defects in control and mutant ddaC neurons at 16 hr APF. (B) ddaC neurons overexpressing patronin RNAi #1 by ppk-Gal4 pruned away most of their dendrites at 32 hr APF. Red arrowheads point to the ddaC somas. Quantification of the severing defects in control and mutant ddaC neurons at 32 hr APF. (C) Compared to FRT G13 control, patronin^c9-c5 ddaC MARCM clones exhibited simple dendrite arbors at wL3 stage. Quantification of number of dendrite termini in control and patronin^c9-c5 ddaC MARCM clones. (D) While the control class I ddaD/ddaE neurons labelled by Gal4^2-21-driven mCD8-GFP pruned their larval dendrites at 20 hr APF, patronin RNAi #1 ddaD/ddaE neurons failed to do so. Red arrows point to the ddaD somas and open arrowheads to the ddaE somas. (E) Like control ddaF neurons, patronin RNAi #1 ddaF neurons labelled by Gal4^109(2)80-driven mCD8-GFP were also eliminated by 16 hr APF. Red arrowheads point to the ddaC somas, and blue arrowheads point to the ddaF somas. Error bars represent S.E.M. The number of samples (n) in each group is shown on the bars. Scale bars represent 50 µm. ***p<0.001 as assessed by two-tailed Student’s t-test.