Fig. 7. Prehairs are oriented towards the highest accumulation of Fz-GFP and Fmi in tsr mutant wings. Shown are: Fz-GFP (A,E); Fmi (B,F); F-actin (C,G); and merged images (D,H; schematics of merged images D',H'). (A-D) Prehairs in a wild-type wing aged 66 hours APF at 18°C. Fz-GFP and Fmi shows the characteristic asymmetrical distribution at the PD boundaries; the zigzag pattern has begun to lose polarity at this stage. F-actin accumulation shows a single prehair pointing distally and aligned with the distal-most vertex of each cell. The merged image shows the overlay of Fz-GFP and F-actin localization. (E-H) Shown is a similarly aged tsr¹³⁹/tsr^V27Q wing. Fz-GFP distribution is interrupted at the distal cell-cell boundaries and accumulates more densely at some cell boundaries (E, dot). Similarly, Fmi is unevenly distributed at PD boundaries. The F-actin accumulation shows prehairs have non-distal orientations and are not aligned through the distal-most vertices. Prehairs appear to have emerged through the PD boundary at the point of a dense accumulation of Fz-GFP and Fmi (H,H').