Feline Lindhout

2 68 Supplementary Figure 4. Microtubule organization during human iPSC-derived neuronal development A. Quantifications of the growth speed of comets pointing in the anterograde (green) or retrograde (blue) direction. N=3 , n=9-4723 traces in 8-23 cells. B. Quantifications of the distance of run length of comets pointing in the anterograde (green) or retrograde (blue) direction. N=3 , n=9-4723 traces in 8-23 cells. C. Schematic illustration of stage 2 (day 5), 3a (day 7) and 3b (day 14) hiPSC-derived neurons. Different locations of the neurons that are imaged have been outlined and annotated. D. Stills from a spinning-disk time-lapse recording of specified neurites transfected with MARCKS- tagRFP_IRES_GFP-MACF18 at specific time points. The top panel is a still of a typical example neurite in MARCKS-tagRFP. The other panels show moving GFP-MT+TIP comets (GFP-MACF18) pointing in either an anterograde direction (green arrowheads) or retrograde direction (blue arrowheads). Red line indicates location of laser severing, and red arrowhead indicates time of laser severing. P indicates the proximal direction and D the distal direction of the neurite. Scale bars: 5 µm. E. Schematic illustration of the proposed distal to proximal reorganization of the axon during stage 3a and stage 3b.