Figure 10.

Early progeny of aISCs lack activation of CASP3 and broadly upregulate DNA damage response transcripts after DXR. (A) Representative images of CASP3 immunofluorescence in crypts of Lgr5^eGFP-CreERT2 reporter mice, using the experimental design in Figure 6A and C. An early progeny cell is indicated by the white dotted line in each experimental group. Scale bar = 10 μm. (B) Quantification of the percentage of CASP3⁺ cells that are Double⁺ aISCs (GFP⁺/tdTomato⁺) or early progeny cells (tdTomato⁺) within the crypt epithelium at 6 hours and 24 hours after DXR as a percentage of total CASP3⁺ cells/crypt (mean ± SD; n = 3 per time point, 10 crypts/mouse). ∗∗P < .01; ∗∗∗∗P < .0001; 2-way analysis of variance followed by Bonferroni’s post hoc test. (C) Mean log2 fold change of DDR–associated transcripts in the indicated populations isolated from control mice 24 hours after TAM (n = 3, normalized to double negative epithelial cells). Cells were isolated via FACS as in Figure 6A. (D) Mean log2 fold change of DDR transcripts in the indicated population 6 hours (n = 2) and 24 hours (n = 3) after DXR. Each cell population was normalized to its control population (n = 3) (Figure 8D) to demonstrate DXR-specific responses within the identified cell type. Cells were isolated via FACS as in Figure 6C. Statistically different gene expression (P values in text) was calculated by 2-way analysis of variance, and the false discovery rate was controlled with the 2-stage step-up method of Benjamini, Krieger, and Yekutieli.