Ran has distinct functions from Aurora A and Plk4 during assembly of a meiosis I spindle. (A) Time-lapse imaging of oocytes injected with EGFP-EB3 (black, inverted) and histone H2B-mRFP (red) mRNAs. Shown are controls and oocytes treated with 1 µM Aurora A inhibitor 1 or 2 µM centrinone. For each condition, oocytes were additionally injected with mRNA encoding dominant-negative RanT24N-mRFP or constitutively active RanQ69L-mRFP. (B–G) Size of projected spindle areas. In untreated control conditions, RanQ69L expression (D and G; n = 22) significantly increases EGFP intensities, whereas RanT24N (C and F; n = 18) decreases these values compared with controls (n = 44). Compared with oocytes treated with Aurora A inhibitor 1 (AurA Inh 1) alone (B–D; n = 21), RanT24N in the presence of Aurora A inhibitor 1 (B and C; n = 13) causes a further reduction in the projected spindle area; RanQ69L (D; n = 13) is not able to significantly rescue these defects. Under inhibition of Plk4 by centrinone treatment (E–G; n = 23), RanT24N (E and F; n = 12) induces a further depression of quantified spindle area throughout time; RanQ69L (G; n = 13) leads to an increase of these values at later time points. Error bars indicate SEM. See also Video 4.