FIG. 7.

A variety of different transcription factor binding sites upstream of two SP1 sites has a greater effect on early viral gene expression than multiple CREB sites. Transfection of recombinant HCMV Towne BAC DNAs and the measurement of CAT activity or viral DNA synthesis were as described in Materials and Methods. (A) Diagram of the HCMV enhancer/unique region substituted by heterologous DNA with one or more CREB sites within a 19-bp repeat sequence upstream of two SP1. (B) Restriction endonuclease AatII digestion of the 1,696-bp PCR DNA product detecting the insertion of one or more 19-bp repeat sequences containing a consensus CREB site inserted into heterologous DNA at positions −137, −323, −406, and −460 relative to the transcription start site (+1). (C) Viral gene expression as measured by CAT activity at 14 days after transfection. Rel., relative. (D) Quantitative PCR of gB DNA at 14 days after transfection. rel, relative.