Fig. 1. Drosophila neck folding during pupal development.
a Dorsal view images of a Drosophila adult (top) and a 14 hAPF pupa (bottom). Arrows, the position of the adult neck. Yellow box, region imaged in (b). b Time-lapse 3D images of Ecad::3xGFP at 18, 21, and 24 hAPF during neck fold formation. See also Supplementary Movie 1. 1–3 Close-ups of the head, neck, and thorax cells in the regions indicated in the left image. Orange arrows indicate the tissue velocity in the thorax and the head from 18 to 21 hAPF and from 21 to 24 hAPF (10 µm h−1, orange arrows in the bottom right). Dashed white line, apical fold front. c 3D image of Ecad::3xGFP and Dfd localizations in the dorsal neck region at 24 hAPF. d Dorsal view of a Drosophila adult showing Dfd > LifeAct::Ruby expression in the adult neck. Note some weak signal is also detected in very small regions of the head. e Transverse view time-lapse images of the neck region labeled by Ecad::3xGPF at 18, 21, and 24 hAPF. Blue line, the position of the apical fold front. Dashed line, midline position. See also Supplementary Movie 1 bottom. f Graph of the apical neck depth (blue, mean ± sem) and of neck deepening speed (green, mean ± sem) as a function of developmental time (N = 10 pupae). Apical neck depth is defined relative to the initial position of the AJ labeled by Ecad::3xGFP at 16 hAPF. Source data are provided as a Source Data file. Scale bars, 50 µm (a–d), 20 µm (e).