Lgr5 egfp mice

C57BL/6J mice were obtained from the Laboratory Animal Research Center of Tsinghua University. Lgr5-EGFP mice were obtained from The Jackson Laboratory. All mice were housed at a specific pathogen–free experimental animal facility at the Laboratory Animal Research Center of Tsinghua University with water and food ad libitum and a 12-h/12-h night/daylight cycle. All mice were backcrossed into the C57BL/6 genetic background for at least 10 generations. C57BL/6 and Lgr5-EGFP mice aged 8–10 wk were used to obtain intestine. Animals were then euthanized, and tissue was processed immediately. All animal experiments were conducted in accordance with the relevant animal regulations with approval of the Institutional Animal Care and Use Committee of Tsinghua University.