FIG. 5.
Mutation of the YY1 binding site results in loss of YY1 binding. (A) The sequence of the HPV-6 E1 promoter extending from the ATG of E7 at nt 528 through the E1 transcriptional start site at nt 680 is provided. The YY1 binding site identified in this study is underlined; the mutations are shown above the wild-type sequence. Putative CDP binding sites on either strand are denoted by a double underline; restriction sites are indicated by a dashed underline. (B) The alignment of the HPV-6 E1p putative YY1 binding site with CCAT-containing YY1 binding sites in HPV-16 (48) and HPV-31 (34) is shown. Nt, the nucleotide position within the genome of the first nucleotide shown under Sequence; r, antisense orientation. (C) EMSAs were conducted using radiolabeled E1p (lanes 1 to 8) or E1pmYY1 (lanes 9 to 16) and unlabeled competitor E1p (lanes 3 to 5 and 11 to 13) or E1pmYY1 (lanes 6 to 8 and 14 to 16).