Figure 4.

The mother centriole is anchored to the cell membrane via appendages. (A) The mother centriole labeled by pmOdf2-mEGFP colocalizes with the cell membrane labeled by FM4-64 in metaphase II. Bar, 5 µm. (B) Oocytes expressing pmPoc1-mEGFP were arrested in metaphase II by MG-132. Mother centriole anchoring was assessed in control cells (DMSO) and in oocytes treated with nocodazole, taxol, or cytochalasin D. 3D volume renderings are shown as in Fig. 3 B. t = 0 corresponds to the time of drug addition, time is in mm:ss. (C) Distance of mother and daughter centrioles to the plasma membrane over time for each oocyte shown in B. Orange vertical lines indicate when the drug effect becomes visible. (D) Serial semi-thin section (130 nm) electron micrographs showing the area encompassing the MII spindle and PBI. The panel shows a montage of selected serial sections containing the four centrioles. (E) 3D reconstruction of the serially sectioned volume. (F) High-magnification images of the four centrioles, showing the relevant sections for each of them. Vesicles are identified by an orange asterisk. Orange arrowheads indicate electron-dense connections to the plasma membrane, reminiscent of mother centriole appendages. (G) Top panel shows another example of a mother centriole attached to vesicles (orange asterisk) via electron dense connections reminiscent of appendages during metaphase II (arrowheads). Bottom panel shows a mother centriole still anchored to the plasma membrane after PBII extrusion; arrowheads indicate attachment points to the plasma membrane. Schematic overviews of the whole area and position of the mother centriole within (green sphere) are depicted. Bars: (D and E) 1 µm; (F and G) 0.5 µm.