Fig. 4: DRP1 degradation is required for metaphase I to anaphase I transition.

a, b Expression (a) and intensities (b) of cell cycle related proteins during oocyte meiosis. β-Tubulin was used as the loading control. c Frequency of CENP-F and DRP1 disaggregation from the kinetochores after NEBD. Stages I–IV of anaphase were determined by the distance of homologous chromosomes after chromosome spreading. Fluorescence intensities of CENP-F (green line), DRP1 (red line) and CREST (magenta line) are shown in the line graph. Measurement direction starts from the left of the kinetochore to the right in the enlarged images. The distance is shown in pixel. d The occurrence of kinetochore types in (c) from three independent replicates. e PB1 extrusion rates in control and Drp1 mRNA injected oocytes at consecutive time points after NEBD. Drp1 mRNA was injected into oocytes 3 h after NEBD. Three independent replicates were performed. f, g PB1 extrusion rates in control, TRIM21 + IgG and TRIM21 + anti-DRP1 oocytes at consecutive time points after NEBD. The injection was performed at 2 h after NEBD (f) or at the GV stage (g). Three independent replicates were performed. h–k Localisation and fluorescence intensity of MAD1 (h, i) and MAD2 (j, k) after DRP1-Trim-Away. Enlarged images show representative results. Three independent replicates were performed for (i, k). Chromosomes were stained with Hoechst 33342 (blue), and kinetochores were marked with CREST (magenta). Data are presented as the mean ± standard deviation (S.D.). P values were calculated based on nonparametric Kruskal–Wallis tests for (e, f and g), or unpaired Student’s t test (two-tailed) for (b, i and k). *P < 0.05, **P < 0.01, and ***P < 0.001. n in graphs refers to the total number of kinetochores in (d, i and k) or oocytes in (e, f and g), respectively. The white dotted frames in (c, h, and j) indicate the region shown in detail. Scale bar: 5 μm. NEBD, nuclear envelope breakdown; PB1, first polar body. Representative blots or stainings from at least three independent repeats are shown. The exact P values for (b, e–g) are provided as a Source Data file. See also in Supplementary Figs. 5–7.