Fig. 2: p57 is required for the maintenance of quiescence in Bmi1high crypt cells.

a Experimental setup for deletion of the maternal allele of the p57 gene in the small intestine. Bmi1-GFP/Villin-CreERT2/p57+/+ (control) and Bmi1-GFP/Villin-CreERT2/p57+/F (p57 CKO) mice were injected intraperitoneally with tamoxifen (50 mg/kg) on 5 consecutive days and were analyzed 3 days after the final injection. b RT-qPCR analysis of relative p57 mRNA abundance in Bmi1high crypt cells isolated as in Fig. 1h from the small intestine of control or p57 CKO mice (n = 3 mice). c Representative immunofluorescence staining of EdU and Bmi1-GFP in the intestine of control and p57 CKO mice 6 h after intraperitoneal injection of EdU (20 mg/kg). Yellow and white arrowheads indicate Bmi1-GFPhigh cells positive or negative for EdU, respectively. Scale bar, 10 μm. d Quantitation of the frequency of EdU+ cells among Bmi1-GFPhigh crypt cells as in c (n = 3 mice). e Representative flow cytometric analysis of the frequency of quiescent (Ki67–PI–) cells in the Bmi1-GFPhigh fraction of intestinal epithelial cells from control and p57 CKO mice treated as in a. f Quantitative analysis for determinations as in e (n = 4 mice). Quantitative data in b are means + SEM, and those in d and f are means ± SEM. *P < 0.05, **P < 0.01, ****P < 0.001 (two-tailed Student’s t test). Source data are provided as a Source Data file.