Since DCLK1 was significantly overexpressed in Rag-1−/− mice in response to CR infection, we further bred DCLK1fl/fl;CDX2-Cre/ERT2 mice with Rag1−/− to generate double knockout (DKO) mice to see whether the DKOs are more susceptible to infectious colitis. The gene discussed is RAG1; the disease is infection.