Extended Data Fig. 3: Selective ablation of epidermal cells reveals F-Cell specification dynamics.

(a) Methodology used for the ablation of individual cells within the abdominal epidermis. Epidermal cells are labelled by the expression of the nuclear marker Diap1-GFP and depicted in grey in all diagrams. A target epidermal cell (arrowhead) is ablated using a high-power femtosecond laser pulse (see Methods), and the behaviour of surrounding cells is tracked over time. After ablations the cells adjacent to the ablated area (asterisks) move towards each other. Note that no changes in levels of expression of the Diap1-GFP reporter in epidermal cells are detectable over time. (b) Epidermal cells (Diap1-GFP, green) and tactile bristle cells (neur > RFP) before and after laser ablation of the F-Cell (white arrowhead). When the F-Cell is ablated at 36-38 hAPF, the neighbouring epidermal cells (asterisks) fill its position over time and expression levels of Diap1-GFP and neur > RFP are selectively enhanced in a single epidermal cell next to the bristle (yellow arrowheads), indicating de novo F-Cell specification (n = 22 F-Cells over 7 pupae from 3 independent experiments). See Supplementary Video 2. (c) Diagram summarizing the findings in (b). (d) Ablation of the F-Cell (arrowhead) as in (b) but performed at 45-50 hAPF. When the F-Cell is ablated after expressing neur > RFP, the cells adjacent to the ablated area (asterisks) do not show de novo expression of neur > RFP or changes in the levels of Diap1-GFP expression over time (n = 27 F-Cells over 9 pupae from three independent experiments. (e) Diagram summarizing the findings in (d). Results are representative of three independent experiments. Scale bars: 5 μm. Full genotypes are listed in Supplementary Table 1.