Differential response of human interferon-beta promoter elements to trans-activation by HSV VP16 and IRF-1

The trans-activation potential of herpes simplex virus (HSV) VP16, either alone or in combination with interferon regulatory factor 1 (IRF-1), was examined using hybrid promoters containing different regulatory elements from the interferon-beta promoter. Coexpression of HSV VP16 and IRF-1 differentially activated the AAGTGA hexamer construct Th(2), the AAAGGA hexamer Thm(2) construct, and the natural IFN-beta promoter. Surprisingly, high concentrations of IRF-1 inhibited expression of the PRDII containing reporter P2(1)/CAT. These results indicate that trans-activation by HSV VP16, acting through distinct cellular transcription factors, may be involved in stimulation of IFN-beta regulatory domains.