Figure 2

Microtubule polarity is initially mixed in dendrites and gradually resolves to minus-end-out. EB1-GFP was expressed in da neurons using elav-Gal4. Movies of EB1-GFP comets were acquired at all stages of dendrite development, and direction of comet movement was analyzed. Individual frames from movies are shown as examples. A stage 1 neuron is shown in (A), and stage 5 in (B). Arrows point to EB1-GFP comets. Quantitation of comet direction is shown in (C). Numbers on bars indicate number of animals analyzed at each time point. The percent of minus-end-out microtubules was calculated from each movie (one movie per animal), and then the averages and standard deviations were calculated at each stage. Standard deviations are shown as the downward error bars. Statistical significance was calculated with an unpaired t-test. Example movies from all stages are shown as Additional files1,2,3,4,5,6,7).