Increased Levels of Interferon Regulatory Element- binding Activities in Nuclei of High

The transient indudion of type I interferon (IFN) genes following a viral infedion involves transcriptional derepression and adivation, mediated by positive and negative fadors which bind to upstream cis-ading elements. We have transfeded the human IFN-�8 gene into primary splenocytes from mice regulated by the ,fI locus and have shown that the exogenous gene is regulated by this locus in a manner similar to that of endogenousIFN genes. Using nuclear extrads from splenocytes of C57BL/6 (If-i") and BALB/c(If-i') mice in gel retardation assays, we found that levels of DNA- binding adivities for the interferon regulatory element and its subelementswere constitutivein nuclear extrads of spleen cells. Levels of DNA binding to the interferon regulatory element were higher in extrads from the nuclei of If-i" mice and thus correlate with the higher levels of human IFN-fl mRNA deteded in these transfeded cells and the transcription of the endogenousIFN genes. Higher levels of DNA-binding/ transcription fadors found in nuclei from spleen cells of If-i" mice may be involved in the expression of the If-i phenotype.