Fluorescence photobleaching analysis of γTub37C in MI spindles. (A) Prebleach (PreB), bleach and recovery images from FRAP assays of γ Tub37C-GFP in the oocyte MI spindle (left) and cytoplasm (right). Time, s. ROI (yellow circles; radius, w = 1.062 μm). The MI spindle (left) is outlined to show its boundaries (pink lines). Bar, 2 μm. (B) Mean normalized fluorescence over time (n = 21), corrected for photobleaching during the assays. For comparison, only the data for the large ROI are shown (spindle, green; cytoplasm, grey). Inset, fits to new reaction-diffusion FRAP recovery model that assumes a conical bleach profile (spindle, purple; cytoplasm, cyan).