Fig. 2: Dlx5-creER marks early perichondrial cells of the fetal cartilage.

a–d Localization of Dlx5-creER⁺, Osx-creER⁺, or Fgfr3-creER⁺ cells at E13.5 (pulsed at E12.5), visualized by cre-inducible R26R^tdTomato reporter, with Col1a1(2.3 kb)-GFP reporters to mark osteoblasts. a E13.5 cartilage template immunostained for SOX9. Left panels: Scale bar: 200 µm. Right panels: magnified view of the boxed areas (1–3). n = 4 mice per each group. b Col1a1(2.3 kb)-GFP; Dlx5-creER; R26R^tdTomato perichondria at E13.5, immunostained for MYH3 (skeletal muscles, left) or EMCN (endothelial cells, right). Grey: DAPI. Scale bar: 20 µm. n = 4 mice per each group. c Quantification of Dlx5-creER⁺, Osx-creER⁺, or Fgfr3-creER⁺tdTomato⁺ cells. Left: percentage of tdTomato⁺ cells among Col1a1-GFP^neg perichondrial cells. Center: percentage of Col1a1-GFP⁺tdTomato⁺ cells among Col1a1-GFP⁺ osteogenic perichondrial cells. Right: percentage of SOX9⁺tdTomato⁺ cells among SOX9⁺ chondrocytes. n = 4 mice per each group. Two-tailed, one-way ANOVA followed by Tukey’s post-hoc test. Data are presented as mean ± s.d. Exact P value is indicated in the figures. d Dlx5-creER and Fgfr3-creER can mark mutually exclusive cell populations in the fetal perichondrium and cartilage template, respectively, whereas Osx-creER marks cells that overlap with those two cell types. Source data are provided as a Source Data file.