The 5' region of the human papillomavirus type 31 upstream regulatory region acts as an enhancer which augments viral early expression through the action of YY1.
Cis-elements which control human papillomavirus early gene expression have previously been localized to sequences in the upstream regulatory region (URR) which are proximal to the E6 open reading frame. These elements include an enhancer element which functions preferentially in keratinocytes as well as promoter elements. The function of the remaining approximate 500-bp region of the URR in regulating viral expression in the high risk papillomaviruses has been largely uncharacterized. In HPV 6, a negative regulator of early expression, or silencer, has been identified in this 5' region of the URR. In this study, we have investigated the role of the 5' portion of the HPV 31 URR in regulating viral expression. Sequences in this region were found to exert a minimal negative effect on homologous or heterologous promoters. In contrast, a 128-bp sequence within this region was found to exhibit enhancer activity on heterologous and homologous promoters. This enhancer also augmented the activity of the previously identified minimum keratinocyte enhancer. The cellular factors, YY1 and TEF-1, were determined by DNase I footprint analysis and electrophoretic mobility shift assays (EMSAs) to bind the 128-bp enhancer. The binding of YY1 to two of these sites was found to be important for enhancer activity.
Kanaya
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Department of Microbiology-Immunology, Northwestern University Medical School, 303 East Chicago Avenue, Chicago, Illinois 60611, USA.
Kyo
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Laimins
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D001483:Base Sequence; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000235:genetics*; D004742:Enhancer Elements, Genetic; D050981:Erythroid-Specific DNA-Binding Factors; D015967:Gene Expression Regulation, Viral; D006801:Humans; D008969:Molecular Sequence Data; D027383:Papillomaviridae / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics*; D050986:YY1 Transcription Factor
D004268:DNA-Binding Proteins; D050981:Erythroid-Specific DNA-Binding Factors; D014157:Transcription Factors; D050986:YY1 Transcription Factor; C494698:YY1 protein, human