THE TAATGARAT MOTIF IN THE HERPES-SIMPLEX VIRUS IMMEDIATE-EARLY GENE PROMOTERS CAN CONFER BOTH POSITIVE AND NEGATIVE RESPONSES TO CELLULAR OCTAMER-BINDING PROTEINS WHEN IT IS LOCATED WITHIN THE VIRAL GENOME

The TAATGARAT motif in the herpes simplex virus (HSV) immediate-early (IE) gene promoters plays a key role in their activation by the Oct-1- Vmw65 complex, but its role in mediating inhibitory effects of cellula r octamer-binding proteins is less clear. We have used indicator virus es containing reporter constructs with different IE promoters driving a reporter beta-galactosidase gene within the viral genome to investig ate this. We showed that deletion of the upstream IE promoter region c ontaining the TAATGARAT motifs abolishes the inhibitory effect of the cellular octamer-binding proteins Oct-2.4 and Oct-2.5 on the viral IE promoter. This inhibitory effect can be restored by addition of a sing le TAATGARAT motif to the minimal promoter within the viral genome. He nce, the TAATGARAT motif can indeed mediate both positive and negative effects of cellular transcription factors when it is located within t he viral genome.