Patronin is required to establish minus-end-out microtubule polarity during dendrite development. (A) Representative images of ddaE neuron embryonic dendrite development. Red line outlines the cell body and dendrite arbor. Axons extend down in all panels. Bar, 5 μm. (B) Quantification of microtubule polarity during development. Numbers on the graph are the total comet numbers collected from 10, 4, 7, 21, 25, 22, 17, 12, and 11 neurons from left to right. **, P < 0.01; ****, P < 0.0001. (C) Representative image and kymograph of EB1-GFP–labeled minus ends entering developing dendrite of ddaE neuron. On the left is the overview of a stage 1–4 ddaE neuron outlined in red. The black box indicates the region where the kymograph on the right was generated. Turquoise lines mark plus ends, and pink lines mark minus ends. Horizontal bar, 5 μm. Vertical bar, 60 s. (D) Representative kymographs of EB1-GFP from late-stage ddaE neurons expressing the indicated RNAi hairpins. Cyan lines mark plus ends. Horizontal bar, 5 μm. Vertical bar, 60 s.