Isolation and Functional Characterization of the Murine Interferon-β1 Promoter

A murine cosmid clone harboring the single-copy interferon-β₁ (IFN-β₁) gene and extended flanking sequences was isolated. The functional IFN-β₁ promoter is contained within a 170-bp DNA fragment located 5′ of the coding sequence. This was shown by fusion of this fragment to a heterologous reporter gene and transient as well as stable expression in mouse L and monkey CV-1 cells. With the help of these functional assays, it could be demonstrated that the 5′-flanking sequences are the target for the typical regulatory action of common type I IFN activators. DNA sequencing reveals a considerable homology to the human IFN-β₁ promoter within the 280 upstream base pairs. The homology is particularly pronounced within the DNA region containing the virus responsive element (VRE). This phenomenon may explain the similarity of both genes in the mode of regulation. The mouse promoter fragment compared with the human equivalent was shown to be several times more efficient in transcriptional activation in murine and primate cells.