Extended Data Fig. 2: Induction of surface ectoderm and salivary gland rudiments in organoid cultures with FGFs.

a, Treatment with FGF7 alone on Day 12 promoted solid epithelial components but was not sufficient to produce branching structures by Day 80 of differentiation. Representative phase-contrast images and immunofluorescence revealed that the Pan-CK⁺ epithelial cells did not express AQP5 and SOX9 on Day 80. Scale bars, 500 μm (left panel), 400 μm (second panel), 50 μm (third and forth panels). n = 8 organoids, 2 independent experiments. b, Treatment with FGF10 alone on Day 12 promoted solid epithelial components but was not sufficient to produce salivary gland organoids by Day 80 of differentiation. Representative phase-contrast images (left) and immunofluorescence revealed that the pan-CK⁺ epithelial cells did not express AQP5 and SOX9 on Day 80. Scale bars, 500 μm (left panel), 400 μm (second panel), 50 μm (third and forth panels). n = 8 organoids, 2 independent experiments.