Supplementary Figure 4: Microtubules and Myosin II are not involved in nucleus positioning.

a: Percentage of migrating versus non-migrating nuclei in Fmn2−/− oocytes injected with Formin 2, untreated, on treatment with Blebbistatin or Taxol. n = 23 oocytes for Fmn2−/− +Fmn2;n = 22 oocytes for Blebbistatin, n = 18 oocytes for Taxol. b: Microtubule (MTs) network organization in untreated oocytes (left) and in oocytes treated with Taxol (right). Oocytes express the marker of microtubule (+) ends EB3-GFP. Time-projections from one movie (frame interval: 357 ms, 480 frames, movie duration: 2 min 51 s), single medial plane. Please note the absence of EB3 comets in the oocyte treated with Taxol, indicative of impaired microtubule network dynamics. Untreated: n = 8 oocytes, treated: n = 7 oocytes. c: Nucleus repositioning following Formin 2 injection into Fmn2−/− oocytes on 100 μM Blebbistatin treatment. Left panel: time-lapse movie of an Fmn2−/− oocyte injected with cRNAs coding for Formin 2 and the nuclear probe Rango (merged in green). Right panel: mean velocities of nucleus centroid (in μm min⁻¹) as a function of time. Black arrow points out the end of nucleus movement, where the velocity stabilizes. n = 10 oocytes. Error bars display SEM. d: Nucleus repositioning on Taxol treatment. Left panel: time-lapse movie of an Fmn2−/− oocyte injected with cRNAs coding for Formin 2 and the nuclear probe Rango (merged in green). Right panel: mean velocities of nucleus centroid (in μm min⁻¹) as a function of time. n = 13 oocytes. Error bars display SEM. Data are aggregated from two independent experiments for Fmn2−/− +Fmn2, Blebbistatin and Taxol in a, c and d. Data shown represent one out of one experiment in b.