Fig. 8: seqFISH maps Sox9+ subsets at E12.5, with Tfap2b+ marking odontogenic and Hic1+ labeling perimysial cells, confirmed by lineage tracing.

a–d Gene expression patterns produced using seqFISH showing co-expression of Sox6 (magenta) and Sox9 (white) (a, b) and Tfap2b (orange) and Sox9 (white) (c, d) in the hard palate region at E12.5. e, f Gene expression patterns produced using seqFISH showing co-expression of Hic1 (green), Myod1 (purple), and Sox9 (white) (e), and Hic1 (green) and Sox9 (white) (f) in the soft palate region at E12.5. Magenta, orange, and green boxes in a, c, and e are enlarged in b, d, and f, respectively. Magenta, orange, and green arrows in a, c, and e indicate regions expressing Sox6, Tfap2b, and Hic1, respectively. White arrows in b, d, and f indicate co-expression of both genes in the same cells. White dashed lines in a, c, and e outline the palatal shelves. g, j RNAScope in situ hybridization for Tfap2b (red) in the hard palate region (g), and Hic1 (red) and Myod1 (green) in the soft palate region (j) at E12.5. Each experiment was independently repeated three times. h, i Immunofluorescence of tdTomato (red) in coronal sections of the hard palate region of Tfap2b-CreER;tdTomato mice at E13.5 (h) and E16.5 (i). Each experiment was independently repeated three times. k, l Immunofluorescence of tdTomato (red) and MyoD (green) in coronal sections of the soft palate region of Hic1-CreER;tdTomato mice at E13.5 (k) and E16.5 (l). Each experiment was independently repeated three times. Injection protocol is illustrated below the figures. White dashed lines outline the palatal shelves in g–l, yellow dashed lines outline the odontogenic epithelium in g–i and the pterygoid plate in l. White arrows indicate positive cells in g–l. Schematic drawings of section orientation and levels are shown on the left for panels a-f and above for panels g–l. Abbreviations: muscle mass (mm), medial pterygoid muscle (mp), tensor veli palatini (tvp), and tamoxifen (TMX). Scale bars: 50 µm in a (for a and c), b (for b and d), e, f, and g (for g–l).