Cellular transcription factors that interact with p6 promoter elements of parvovirus B19

All transcripts of the human parvovirus B19 identified so far are regulated by a single promoter at map unit 6 of the viral genome, the so-called p6 p romoter. This promoter is active in a wide variety of different cells. In o rder to identify cellular transcription factors involved in regulating prom oter activity, we performed gel-retardation and supershift assays using the parts of the p6 promoter sequence shown previously to be protected in foot print experiments. Thereby, binding was demonstrated of the Oct-1 protein t o an octamer motif within the p6 promoter and of the transcription factor S p1 to three GC boxes. A specific preferential interaction of the factor Sp3 with one of these boxes was observed, indicating that the ratio Sp1:Sp3 ma y be involved in the regulation of promoter activity, Consensus sites for t he regulatory protein YY1 are located close to the GC boxes and the octamer motif, to which this factor binds efficiently.