Fmn2-mediated actin assembly exerts a pushing force. (A) Fmn2 around the spindle remnant (outline pointed by arrows). (B) Distribution of actin filaments around the spindle remnant during spindle migration. (C) Time-lapse images of a representative oocyte undergoing chromosome migration in the presence of colcemid. Numbers indicate hours and minutes. (D) Angular distribution (n = 8) of chromosome migration (after spindle disassembly) relative to the spindle remnant–chromosome axis. (E) Angular distribution (n = 11) of spindle migration relative to the long spindle axis. (F) Expression of Fmn2-mCherry in oocytes that failed GVBD causes GV (outlined area in the transmitted light images or the dark area in the GFP channel) deformation and migration to the cortex. An enrichment of F-actin (labeled with UtrCH-GFP) can be observed in the area of deformation. (G and H) Time-lapse images of a representative oocyte undergoing GV (the dark area excluding UtrCH-GFP signal) migration upon Fmn2-mCherry expression. Yellow outlines the initial position of the GV, and red outlines the end position. (H) Kymograph generated along the red line in G. Bars: (A–C and F) 20 µm; (G and H) 10 µm.