Fig. 3: Villus cluster PDGFRα expression is Foxl1 dependent.
From: Villification of the intestinal epithelium is driven by Foxl1 through activation of PDGFRα and BMPs
A Telocytes labeled by tdTomato expression driven by the Foxl1 cis-regulatory elements (red) are retained in Foxl1 null mice. Epithelial cells are labeled by E-cadherin (green). Quantification of the density of tdTomato-positive cells in mice heterozygous (control) or homozygous (Foxl1) for the Foxl1-tdTomato allele as either number of telocytes per linear distance or as proportion of submucosal cells. N = 3 embryonic day 15.5 embryos per genotype. Data are presented as mean +/- standard deviation. Statistical significance was assessed using an unpaired two-tailed t-test with Welch’s correction. ns, p = 0.2305 (upper panel); ns, p = 0.2452 (lower panel). B UMAP plot of scRNAseq data comparing control and Foxl1 null fetal gut shows dramatic shifts in both telocyte progenitor (blue box) as well as in epithelial cells (green box). Single cells are color-coded by genotype. Three embryos per genotype, all from the same litter, were used. C UMAP plot showing Pdgfra expression in control and Foxl1 null telocyte progenitors. D Violin plot of Pdgfra expression in control and Foxl1 null telocyte progenitors. Cells identified as smooth muscle cells are shown for comparison. Statistical significance was assessed using a two-sided Wilcoxon rank-sum test. Smooth muscle cell: ns, p = 0.77; Telocyte prog-1: ****, p < 2 × 10⁻16; Telocyte prog-2: ns, p = 0.71. E Immunofluorescence labeling confirms dramatic reduction in PDGFRα expression (red) in the absence of Foxl1. The apical membrane of epithelial cells is stained for Ezrin (green). F Maximum intensity projection of anterior small intestine stained in whole mount with an antibody to Pdgfra (red), and counterstained with DAPI (blue) to label nuclei. For imaging analyses (E, F), 3–5 embryos per genotype at the indicated developmental stages were examined, and representative images are shown.
