Fig. 1: The inducible VND7 system drives ectopic microtubule rearrangements.
a Long-term time-lapse recording of microtubule rearrangements at low-temporal resolution in an induced hypocotyl cell. Scale bar = 3 µm. Microtubule bands emerge close to each other but merge into one band over time (arrows). b Kymograph along dashed line in a reveals the emergence (arrowheads) and merging (asterisks) of microtubule bands. Scale bars = 30 min and 3 µm. c Periodogram of the kymograph in a reveals the development of a dominant microtubule spacing of 5.3 ± 0.5 µm (mean ± SEM, 6 cells, 4 seedlings). d The relative power spectral density (PSD) measured at the dominant spacing of four individual cells (grey lines) increases from 5.5 ± 0.3% (thick line, mean ± SEM) to 26.9 ± 0.5% within 2 h. e Microtubule noise (i.e., intensity s.d. normalized to sum intensity) decreases rapidly in gaps from 15 ± 5% (thick line, mean ± SD) to 5 ± 1%. f Long-term time-lapse recording at high temporal resolution of YFP-labelled microtubules in an induced hypocotyl cell. Scale bar = 5 µm. g Image series of box in f colour-coding for growing (green) and shrinking (magenta) microtubule ends. A dynamic microtubule end is highlighted by arrowheads. Scale bar = 5 µm. h Classification of microtubule bands (orange) and gaps (blue). i, j Kymographs along the dashed lines in g. In gaps, growing microtubule ends often undergo catastrophes (empty arrowheads) and rarely rescues (filled arrowheads). In contrast, microtubule ends in bands predominantly grow along the band axis and are often rescued after catastrophe. Scale bars = 2 µm and 100 s. k–n Quantification of microtubule dynamics in four time series’ (fine lines, numbered in k and m, thick line = time average) divided into bands (orange) and gaps (blue): k, m individual and l, n pooled catastrophe rates rcat and rescue rates rres, respectively. Data pooled from 35 time points from four cells (AVG); means ± 95% confidence intervals. Statistics: Welch’s unpaired, two-sided t-test, p = 0.0021 (l) and p = 0.0107 (n).
