Vil1-MerCreMer mice were generated by inserting a Tamoxifen-inducible Cre recombinase protein MerCreMer gene expression element controlled by the mouse Vil1 promoter into the mouse H11 safe harbor site. Before induction, MerCreMer is only present in the cytoplasm and can only enter the nucleus to exert its recombination effect after Tamoxifen treatment. When bred with mice containing a loxP site-flanked sequence, Cre recombinase-mediated deletion of the flanked sequence will occur in the villous and crypt epithelial cells of the small and large intestines of the offspring after Tamoxifen induction. The onset of endogenous mouse Vil1 gene expression is at 9.0dpc, and the onset of Cre recombinase expression in this strain is approximately 12.5dpc.