Live Imaging of Embryonic Mandibular Arch

Live image acquisition was performed by submerging embryos were submerged in 50% rat serum in DMEM without phenol red (Invitrogen) in a 25 mm imaging chamber. Cheese cloth was used to immobilise the embryo and position the mandibular arch directly against the coverglass. Embryos were imaged in a humidified chamber at 37 °C in 5% CO₂^{7 (link),23 (link)}. Time-lapse images were acquired on a Quorum WaveFX-X1 spinning disk confocal system (Quorum Technologies Inc.) at 20× magnification. Images were processed with Volocity software or ImageJ/Fiji. Representative images are shown from at least three independent experiments for each condition, and unless otherwise indicated, from at least three independent cohorts. No statistical method was used to predetermine sample size. Experiments were not randomised. Investigators were not blinded to allocation during experiments and outcome assessment.