Extended Data Fig. 6: EGFR signalling is required for F-Cell specification.
(a) Expression the EGFR signalling reporter aos-GFP (green), together with neur > RFP, in rl/ERK mutant background (rl1/rl10a). (b) Uniform Diap1-GFP and absence of neur > RFP expression in epidermal cells surrounding bristles expressing of EGFRDN. See Fig. 3e for quantifications. (c) Uniform Diap1-GFP and absence of neur > RFP expression in epidermal cells surrounding bristles in a rl/ERK mutant background. See Fig. 3e for quantifications. (d) Top row: diagram of the tactile bristle when EGFR signalling is active (presence of the F-Cell) or impaired (absence of the F-Cell). Middle row: expression of neur > RFP and of the socket cell-specific reporter Su(H)-ASE5-GFP (green) at 60 hAPF when EGFR signalling is active or impaired. Bottom row: bright field images showing the shape of the cuticular socket and hair shaft at 90 hAPF in each condition. Note that the cuticular sockets and hair shafts appear unaffected by impaired EGFR signalling. (e) Right, Diap1-GFP expression in the epidermis showing F-Cells adjacent to control bristles (white arrowheads), but not next to bristles lacking spi/EGF activity in the shaft cells (yellow arrowhead; See Methods). Centre: zoomed-in view of the bristle lacking spi/EGF activity in the shaft cells from the left panel, with diagram summarising the result on top. (f) Quantification of Diap1-GFP fluorescence intensity in F-Cells and epidermal cells next to shaft cells lacking spi/EGF (n = 9 clones per genotypes in 8 flies at pupal stage). In the dot plots the mean is marked in red and error bars represent SEM. The unpaired two-tailed Student’s t-test for equal mean was applied (p > 0.05, NS: not significant). Results are representative of three independent experiments. Scale bars: 5 μm. Full genotypes for are listed in Supplementary Table 1. Numerical data and exact P values are available in source data.
