Figure 1.

KLF5 is required for intestinal stem cell self-renewal. (A) Scheme of the experimental plan. Eight- to 12-week-old Lgr5^Ctrl and Lgr5^ΔKlf5 mice were injected with tamoxifen for 5 consecutive days and sacrificed at 0, 2, 5, 9, 12,19, 33, or 61 days after the first injection. Mice were injected with EdU 3 or 24 hours before sacrifice. Lgr5^EGFPhi cells were FACS-isolated for 3-dimensional enteroid culture, RNA-seq, and ChIP-seq at day 5. (B) Representative immunofluorescence images of EGFP, RFP, KLF5, and DAPI in the PSI crypts of Lgr5^Ctrl and Lgr5^ΔKlf5 mice. KLF5 expression was observed in Lgr5^EGFPhi cells at the base of the crypts (magenta arrowheads), as well as cells in the TA zone (yellow brackets). Scale bars represent 20 μm. (C) Quantification of average number of Lgr5^EGFPhi cells per crypt. (D) Representative immunofluorescence images of RFP, KLF5, EdU, and DAPI of PSI crypts of Lgr5^Ctrl and Lgr5^ΔKlf5 mice. Mice were treated with 3 hours EdU pulse. Scale bar represents 20 μm. (E–G) Quantification of (E) EdU-incorporated RFP⁺, (F) an average number of RFP⁺, and (G) total cells per crypt. Data are expressed as mean ± SD, 20 crypts quantified per mouse (E–G), n = 3–5 mice per group. ∗P < .05, ∗∗P < .01 by linear mixed regression models.