Figure 1. Rab27a is a marker for cortical granules.

(a) Oocyte expressing GFP-Rab27a, fixed and stained with lens culinaris agglutinin, a cortical granule marker. Scale bar, 20 μm. (b) Quantification of the colocalization of Rab27a puncta with lens culinaris agglutinin puncta (mean±s.d. from three experiments). Total number of Rab27a puncta quantified are indicated. (c) Cortical granules visualized with GFP-Rab27a translocate from the centre of oocytes to the cortex, where they become enriched. Scale bars, 20 μm (overview) and 5 μm (enlarged). (d) Schematic diagram of the quantification methods for cortical granule translocation and enrichment at the cortex. Scale bars, 20 μm. (e) Cortical granule dynamics in the oocyte centre during meiotic maturation. Three separate phases can be identified in the cell centre, which are colour-coded in all subsequent graphs. The start and end of each phase was determined by calculating the derivative of the data. (f) Cortical granule enrichment at the oocyte cortex during meiotic maturation. The three separate phases identified in the cell centre are colour-coded.