Fig. 5. Localization of CNN at the female meiotic spindle. Projected series of optical sections of oocytes stained with antibodies against ß-tubulin (green) and CNN (orange). In each panel the inset shows, in monochrome, the localization of CNN protein. (A) Anaphase I: CNN accumulates on distinct bundles at the central spindle (arrow). (B) Prophase II: the protein accumulates at the middle of the spindle in a punctate ring-like structure (arrowheads) that surrounds a faint localization (asterisk) on the interior MT bundles; punctate aggregates of the protein are also found at the center of the MT asters (arrows). (C) Prometaphase II: the CNN localization at the middle of the spindle decreases in intensity (asterisk), although a thin ring-like fluorescent structure is still visible (arrowheads); the protein has also accumulated at the focus of the cytoplasmic asters (arrows). (D) Metaphase II, (E) anaphase II: CNN staining is no longer found within the spindles, but a distinct accumulation is visible at the focus of the central aster (arrows). (F) CNN aggregates are also observed within the sperm aster, at the sites of MT clustering (arrows). Bar, 2 µm.