Interferon activates promoter of Nmi gene via interferon regulator factor-1

N-Myc interactor (Nmi) is reported to participate in many activities, such as signaling transduction, transcription regulation, and antiviral responses. As Nmi may play important roles in interferon (IFN)-induced responses, we investigated the mechanism how Nmi protein is regulated. We identified and cloned the promoter of Nmi gene. Sequence analysis and luciferase assays shown that an IFN-stimulated response element (ISRE) and a GC box in the promoter were essential for the basal transcription activity of Nmi gene. We also found that interferon regulatory factor 1 (IRF-1) could activate transcription of Nmi by binding to the ISRE in the promoter. Knockdown of IRF-1 decreases IFN-induced Nmi transcription. These results revealed that IRF-1 is involved in the IFN-inducible expression of Nmi.