Posterior oskar mRNA is lost shortly after Par-1, and microtubules polymerize with long delay. (A) Two-color time-lapse images of an egg chamber expressing GFP::Par-1 in the germline (cyan) and osk::MS2-MCP::mCherry (magenta) before (−1 min) and after ablation of PFCs (yellow dashed circle). Scale bar, 20 µm (B) Zoom-in of the posterior of the egg chamber shown in panel A. Top: GFP::Par-1, bottom: osk::MS2-MCP::mCherry. Both Par-1 and osk delocalize from the cortex facing ablated PFCs. Scale bar, 20 µm. (C) Intensity of Par-1 (top) and oskar mRNA (bottom) at the posterior of the oocyte facing ablated PFCs, for stages 8 (n = 2), 9 (n = 7), and 10A (n = 6). Thin dashed lines are individual experiments, the solid lines are the averages for each stage, and the black dashed line represents a fit to a single exponential decay with time delay (see Materials and methods). While Par-1 signal loss is immediate, oskar mRNA decreases with increasing delay; the estimated 95% confidence interval (min) are for stage 8: (13.3, 16.5), stage 9: (15.5, 18.9), and stage 10A: (24.4, 36.0). (D) Two-color time-lapse images of an egg chamber expressing Jupiter::GFP (green) and osk::MS2-MCP::mCherry (magenta) before (−1 min) and after ablation of PFCs. This example shows microtubule growth at the posterior 80–90 min following ablation. Scale bar, 20 µm. (E) As in D, showing an example of an oocyte that did not yet exhibit microtubule growth 90 min after PFC ablation. Scale bar, 20 µm.