Fig. 2. Ectopic expression of TUBB8 delayed meiotic progression mainly by SAC activation.

a Statistical analysis of PB1 extrusion rates in mouse oocytes expressing different human tubulin isotypes at consecutive time points after NEBD. n, number of oocytes. b Statistical analysis of PB1 extrusion time in mouse oocytes expressing different human tubulin isotypes. n, number of oocytes. One-way ANOVA with multiple comparisons test. NS, not significant. c Representative images of SAC activity as indicated by localization of BUBR1 at late MI in mouse oocytes expressing different human tubulin isotypes. BUBR1 signal was shown in a separate channel. Mouse GV oocytes were injected with vehicle, 5’FLAG-TUBB4A-cRNA (200 ng/μL), 5’FLAG-TUBB8-cRNA (200 ng/μL), or a combination of 5’FLAG-KIF11 (1000 ng/μL) and 5’FLAG-TUBB8-cRNA (400 ng/μL), maintained for 1 h in 2.5 μM milrinone, and then washed and transferred into milrinone-free M2 medium to allow the resumption of meiosis. At 5 h after NEBD, oocytes were fixed and immunostained for BUBR1, ACA, and DNA (using Hoechst), Scale bar, 5 μm. d Relative intensities of BUBR1 normalized to signal intensities of ACA. n, number of kinetochores. One-way ANOVA with multiple comparisons test. ****P < 0.0001. e Statistical analysis of PB1 extrusion rates at consecutive time points after NEBD for controls and mouse oocytes expressing TUBB8 with or without reversine (100 nM) treatment. n, number of oocytes. Data in a, b, d, and e were collected from at least three independent experiments.