Fig. 4: A mitochondria-rich subcortical layer overlaps with the high-actin-density domain during CP initiation.
a, Confocal fluorescence images of maximum intensity projections of the myoplasm (MitoTracker Deep Red FM) (top row) and cortical actin (Utrophin-Venus) (bottom row) in an exemplary oocyte during consecutive stages of CP initiation. Dashed line demarcates the edge of the compacted myoplasm layer in the vegetal hemisphere of the oocyte. Scale bar, 30 µm. b, EM section of an exemplary region in the vegetal hemisphere of an unfertilized oocyte (outlined in the schematics on the left). Note the ER sheets in the myoplasm. Scale bar, 1 µm. b′, Three-dimensional reconstruction of 50 sections of 70 µm taken in the same region shown in b. Mitochondria, blue; cER, red; granules, grey. For clarity, only cER from the first sections is shown. c, Confocal fluorescence images of the myoplasm (MitoTracker Deep Red FM) at the VP in an exemplary unfertilized oocyte before and after UV-laser cutting. Scale bar, 15 µm. c′, Kymograph of myoplasm recoil following UV-laser cutting as a function of time after the cut. Horizontal scale bar, 5 sec. Vertical scale bar, 2 µm. 3D, three-dimensional; M, mitochondria; G, granules.
