Fig. 4: Myosin X and Myosin VIIb have overlapping functions in regulating spindle-localized F-actin and pMTOC organization.

A Representative confocal images of metaphase I oocytes microinjected with control siRNA, Myosin X siRNA, Myosin VIIb siRNA or Myosin X siRNA + Myosin VIIb siRNA at the germinal vesicle stage. The oocytes were immunostained with pericentrin antibody (MTOCs) and stained with phalloidin (F-actin) and 4′,6-diamidino-2-phenylindole, dihydrochloride (DAPI, DNA). B Quantification of average spindle-localized F-actin in (A). Each dot in the plot represents the value obtained from an individual biological replicate. C Representative confocal images of a metaphase I oocyte expressing mRuby fused to full-length mouse myosin VIIb (mRuby-MyoVIIb, pseudo-cyan) immunostained with pericentrin antibody (pMTOCs, magenta). D Representative confocal images of metaphase I oocytes microinjected with MyoX siRNA or MyoX siRNA + MyoVIIb cRNA at the germinal vesicle stage. The oocytes were labeled with phalloidin (F-actin, gray) and pericentrin (pMTOCs, magenta). DNA was labeled with DAPI (blue). Scale bar represents 10 μm. E Plot profile of pMTOCs (pericentrin fluorescence) along the longitudinal axis of the spindle in the groups indicated in (D). F Quantification of pMTOC volume at the spindle poles to the total volume of all pMTOCs in the spindle. G Average pMTOC number quantification after 3D reconstruction of pericentrin from oocytes in (D). H Average pMTOC volume quantification after 3D reconstruction of pericentrin from oocytes in (D). I Average spindle-localized F-actin fluorescence intensity of oocytes indicated in (D). J Average cytoplasmic F-actin fluorescence intensity of oocytes indicated in (D). Data are represented as means ± SEM. Asterisks represent significant differences, **p < 0.01, ***p < 0.001, and ****p < 0.0001. The total number of analyzed oocytes per each experimental group (from 3 independent replicates) is specified above each graph.