Patronin function during dendrite regeneration is required for outgrowth and establishment of microtubule polarity. (A) Representative images of ddaC neurons expressing mCD8-GFP immediately after or 24 h after dendrite severing. Bar, 50 μm. Red arrowheads indicate cut sites. (B) Quantification of dendrite regeneration. 24 h after dendrite injury, the greatest diameter of the regenerated dendrite arbor was measured. Averages and SDs are shown as well as data from each neuron. *, P < 0.05; **, P < 0.01 with a t test. (C) Representative image and kymographs or EB1-TagRFP-T and YFP-Patronin in regenerating dendrites. Left: Overview of merged channels showing regeneration 24 h after dendrite injury. Bar, 25 μm. Right: Kymographs showing minus ends labeled by EB1-TagRFP-T and YFP-Patronin growing toward the dendrite tip. Pink lines mark the minus ends. Horizontal bar, 5 μm. Vertical bar, 60 s. (D) Quantification of microtubule polarity during dendrite regeneration. Microtubule polarity was measured at 16, 24, or 48 h after dendrite injury in regenerating ddaC dendrites. Neurons expressed EB1-GFP as well as the indicated RNAi hairpins. Numbers on the graph are the total comet numbers collected from 15, 8, 14, 12, 7, and 9 neurons from left to right. ****, P < 0.0001 with Fisher’s exact test. (E) Representative kymographs of EB1-GFP in regenerating dendrite at 24 h after dendrite injury. Turquoise lines mark plus ends. Horizontal bar, 5 μm. Vertical bar, 60 s.