FIG. 5.

The proximal JC virus promoter contains multiple protein factor binding sites. (A) Schematic diagram of the upstream regulatory region of the JC virus promoter. AP1 and NF-1 binding sites were identified in the enhancer region. The three Sp1 binding sites identified are marked by open boxes and solid lines. The 5′ proximal region also contains pentanucleotide repeats and TATA box sequences. Downstream of the Sp1-II site, a novel sequence which was predominantly protected by U87MG nuclear extract was identified. T-antigen binding sites are also marked by solid lines. The arrow indicates the transcription start site. (B) Nucleotide sequence of the MH1 JC virus promoter from bp −100 to +100 (11). Nuclear protein binding sites as well as the T-antigen and Sp1 binding sites are represented by solid lines. The dotted line on the AP1 site indicates a sequence bound by only U87MG nuclear extracts. The arrow at +1 denotes the transcription initiation site of the JC virus early gene.