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. 1992 Dec 25;20(24):6701–6706. doi: 10.1093/nar/20.24.6701

Activation of human papillomavirus type 18 E6-E7 oncogene expression by transcription factor Sp1.

F Hoppe-Seyler 1, K Butz 1
PMCID: PMC334589  PMID: 1336181

Abstract

The human papillomavirus 18 (HPV18) E6 and E7 proteins are considered to be primarily responsive for the transforming activity of the virus. In order to analyse the molecular mechanisms resulting in viral oncoprotein expression, it is necessary to identify the factors involved in the transcriptional regulation of the E6/E7 genes. Here we define by gel retardation experiments a sequence aberrant Sp1 binding site present in the promoter proximal part of the viral transcriptional control region (Upstream Regulatory Region, URR). Functional analyses employing transient reporter assays reveal that this Sp1 element is required for an efficient stimulation of the HPV18 E6/E7-promoter. Mutation of the Sp1 element in the natural context of the HPV18 URR leads to a strong decrease in the activity of the E6/E7-promoter in several cell lines. The magnitude of reduction varies between different cell types and is higher in cell lines of epithelial origin when compared with nonepithelial cells. Cotransfection assays using Sp1 expression vector systems further define the promoter proximal HPV18 Sp1 binding motif as a functional Sp1 element in vivo and show that its integrity is essential for the stimulation of the E6/E7-promoter by augmented levels of Sp1. These results indicate, that the cellular transcription factor Sp1 plays an important role for the stimulation of the E6/E7-promoter by the viral URR and represents a major determinant for the expression of HPV18 transforming genes E6 and E7.

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Selected References

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  1. Barbosa M. S., Vass W. C., Lowy D. R., Schiller J. T. In vitro biological activities of the E6 and E7 genes vary among human papillomaviruses of different oncogenic potential. J Virol. 1991 Jan;65(1):292–298. doi: 10.1128/jvi.65.1.292-298.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Bedell M. A., Jones K. H., Grossman S. R., Laimins L. A. Identification of human papillomavirus type 18 transforming genes in immortalized and primary cells. J Virol. 1989 Mar;63(3):1247–1255. doi: 10.1128/jvi.63.3.1247-1255.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Boukamp P., Petrussevska R. T., Breitkreutz D., Hornung J., Markham A., Fusenig N. E. Normal keratinization in a spontaneously immortalized aneuploid human keratinocyte cell line. J Cell Biol. 1988 Mar;106(3):761–771. doi: 10.1083/jcb.106.3.761. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Chen C., Okayama H. High-efficiency transformation of mammalian cells by plasmid DNA. Mol Cell Biol. 1987 Aug;7(8):2745–2752. doi: 10.1128/mcb.7.8.2745. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Chong T., Chan W. K., Bernard H. U. Transcriptional activation of human papillomavirus 16 by nuclear factor I, AP1, steroid receptors and a possibly novel transcription factor, PVF: a model for the composition of genital papillomavirus enhancers. Nucleic Acids Res. 1990 Feb 11;18(3):465–470. doi: 10.1093/nar/18.3.465. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Cole S. T., Danos O. Nucleotide sequence and comparative analysis of the human papillomavirus type 18 genome. Phylogeny of papillomaviruses and repeated structure of the E6 and E7 gene products. J Mol Biol. 1987 Feb 20;193(4):599–608. doi: 10.1016/0022-2836(87)90343-3. [DOI] [PubMed] [Google Scholar]
  7. Dignam J. D., Lebovitz R. M., Roeder R. G. Accurate transcription initiation by RNA polymerase II in a soluble extract from isolated mammalian nuclei. Nucleic Acids Res. 1983 Mar 11;11(5):1475–1489. doi: 10.1093/nar/11.5.1475. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Dyson N., Howley P. M., Münger K., Harlow E. The human papilloma virus-16 E7 oncoprotein is able to bind to the retinoblastoma gene product. Science. 1989 Feb 17;243(4893):934–937. doi: 10.1126/science.2537532. [DOI] [PubMed] [Google Scholar]
  9. Dyson N., Howley P. M., Münger K., Harlow E. The human papilloma virus-16 E7 oncoprotein is able to bind to the retinoblastoma gene product. Science. 1989 Feb 17;243(4893):934–937. doi: 10.1126/science.2537532. [DOI] [PubMed] [Google Scholar]
  10. Fromental C., Kanno M., Nomiyama H., Chambon P. Cooperativity and hierarchical levels of functional organization in the SV40 enhancer. Cell. 1988 Sep 23;54(7):943–953. doi: 10.1016/0092-8674(88)90109-2. [DOI] [PubMed] [Google Scholar]
  11. Garcia-Carranca A., Thierry F., Yaniv M. Interplay of viral and cellular proteins along the long control region of human papillomavirus type 18. J Virol. 1988 Nov;62(11):4321–4330. doi: 10.1128/jvi.62.11.4321-4330.1988. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Gloss B., Bernard H. U. The E6/E7 promoter of human papillomavirus type 16 is activated in the absence of E2 proteins by a sequence-aberrant Sp1 distal element. J Virol. 1990 Nov;64(11):5577–5584. doi: 10.1128/jvi.64.11.5577-5584.1990. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Gloss B., Yeo-Gloss M., Meisterenst M., Rogge L., Winnacker E. L., Bernard H. U. Clusters of nuclear factor I binding sites identify enhancers of several papillomaviruses but alone are not sufficient for enhancer function. Nucleic Acids Res. 1989 May 11;17(9):3519–3533. doi: 10.1093/nar/17.9.3519. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Ham J., Dostatni N., Arnos F., Yaniv M. Several different upstream promoter elements can potentiate transactivation by the BPV-1 E2 protein. EMBO J. 1991 Oct;10(10):2931–2940. doi: 10.1002/j.1460-2075.1991.tb07843.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Hoppe-Seyler F., Butz K., Rittmüller C., von Knebel Doeberitz M. A rapid microscale procedure for the simultaneous preparation of cytoplasmic RNA, nuclear DNA binding proteins and enzymatically active luciferase extracts. Nucleic Acids Res. 1991 Sep 25;19(18):5080–5080. doi: 10.1093/nar/19.18.5080. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Hoppe-Seyler F., Butz K., zur Hausen H. Repression of the human papillomavirus type 18 enhancer by the cellular transcription factor Oct-1. J Virol. 1991 Oct;65(10):5613–5618. doi: 10.1128/jvi.65.10.5613-5618.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Li R., Knight J. D., Jackson S. P., Tjian R., Botchan M. R. Direct interaction between Sp1 and the BPV enhancer E2 protein mediates synergistic activation of transcription. Cell. 1991 May 3;65(3):493–505. doi: 10.1016/0092-8674(91)90467-d. [DOI] [PubMed] [Google Scholar]
  18. Mack D. H., Laimins L. A. A keratinocyte-specific transcription factor, KRF-1, interacts with AP-1 to activate expression of human papillomavirus type 18 in squamous epithelial cells. Proc Natl Acad Sci U S A. 1991 Oct 15;88(20):9102–9106. doi: 10.1073/pnas.88.20.9102. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Münger K., Phelps W. C., Bubb V., Howley P. M., Schlegel R. The E6 and E7 genes of the human papillomavirus type 16 together are necessary and sufficient for transformation of primary human keratinocytes. J Virol. 1989 Oct;63(10):4417–4421. doi: 10.1128/jvi.63.10.4417-4421.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Nakshatri H., Pater M. M., Pater A. Ubiquitous and cell-type-specific protein interactions with human papillomavirus type 16 and type 18 enhancers. Virology. 1990 Sep;178(1):92–103. doi: 10.1016/0042-6822(90)90382-2. [DOI] [PubMed] [Google Scholar]
  21. Ondek B., Gloss L., Herr W. The SV40 enhancer contains two distinct levels of organization. Nature. 1988 May 5;333(6168):40–45. doi: 10.1038/333040a0. [DOI] [PubMed] [Google Scholar]
  22. Pascal E., Tjian R. Different activation domains of Sp1 govern formation of multimers and mediate transcriptional synergism. Genes Dev. 1991 Sep;5(9):1646–1656. doi: 10.1101/gad.5.9.1646. [DOI] [PubMed] [Google Scholar]
  23. Pugh B. F., Tjian R. Mechanism of transcriptional activation by Sp1: evidence for coactivators. Cell. 1990 Jun 29;61(7):1187–1197. doi: 10.1016/0092-8674(90)90683-6. [DOI] [PubMed] [Google Scholar]
  24. Romanczuk H., Villa L. L., Schlegel R., Howley P. M. The viral transcriptional regulatory region upstream of the E6 and E7 genes is a major determinant of the differential immortalization activities of human papillomavirus types 16 and 18. J Virol. 1991 May;65(5):2739–2744. doi: 10.1128/jvi.65.5.2739-2744.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Saffer J. D., Jackson S. P., Thurston S. J. SV40 stimulates expression of the transacting factor Sp1 at the mRNA level. Genes Dev. 1990 Apr;4(4):659–666. doi: 10.1101/gad.4.4.659. [DOI] [PubMed] [Google Scholar]
  26. Schwarz E., Freese U. K., Gissmann L., Mayer W., Roggenbuck B., Stremlau A., zur Hausen H. Structure and transcription of human papillomavirus sequences in cervical carcinoma cells. Nature. 1985 Mar 7;314(6006):111–114. doi: 10.1038/314111a0. [DOI] [PubMed] [Google Scholar]
  27. Spalholz B. A., Vande Pol S. B., Howley P. M. Characterization of the cis elements involved in basal and E2-transactivated expression of the bovine papillomavirus P2443 promoter. J Virol. 1991 Feb;65(2):743–753. doi: 10.1128/jvi.65.2.743-753.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
  28. Tan S. H., Gloss B., Bernard H. U. During negative regulation of the human papillomavirus-16 E6 promoter, the viral E2 protein can displace Sp1 from a proximal promoter element. Nucleic Acids Res. 1992 Jan 25;20(2):251–256. doi: 10.1093/nar/20.2.251. [DOI] [PMC free article] [PubMed] [Google Scholar]
  29. Thierry F., Spyrou G., Yaniv M., Howley P. Two AP1 sites binding JunB are essential for human papillomavirus type 18 transcription in keratinocytes. J Virol. 1992 Jun;66(6):3740–3748. doi: 10.1128/jvi.66.6.3740-3748.1992. [DOI] [PMC free article] [PubMed] [Google Scholar]
  30. Thierry F., Spyrou G., Yaniv M., Howley P. Two AP1 sites binding JunB are essential for human papillomavirus type 18 transcription in keratinocytes. J Virol. 1992 Jun;66(6):3740–3748. doi: 10.1128/jvi.66.6.3740-3748.1992. [DOI] [PMC free article] [PubMed] [Google Scholar]
  31. Vande Pol S. B., Howley P. M. The bovine papillomavirus constitutive enhancer is essential for viral transformation, DNA replication, and the maintenance of latency. J Virol. 1992 Apr;66(4):2346–2358. doi: 10.1128/jvi.66.4.2346-2358.1992. [DOI] [PMC free article] [PubMed] [Google Scholar]
  32. Werness B. A., Levine A. J., Howley P. M. Association of human papillomavirus types 16 and 18 E6 proteins with p53. Science. 1990 Apr 6;248(4951):76–79. doi: 10.1126/science.2157286. [DOI] [PubMed] [Google Scholar]
  33. Westin G., Schaffner W. Heavy metal ions in transcription factors from HeLa cells: Sp1, but not octamer transcription factor requires zinc for DNA binding and for activator function. Nucleic Acids Res. 1988 Jul 11;16(13):5771–5781. doi: 10.1093/nar/16.13.5771. [DOI] [PMC free article] [PubMed] [Google Scholar]
  34. Yee C., Krishnan-Hewlett I., Baker C. C., Schlegel R., Howley P. M. Presence and expression of human papillomavirus sequences in human cervical carcinoma cell lines. Am J Pathol. 1985 Jun;119(3):361–366. [PMC free article] [PubMed] [Google Scholar]
  35. von Knebel Doeberitz M., Oltersdorf T., Schwarz E., Gissmann L. Correlation of modified human papilloma virus early gene expression with altered growth properties in C4-1 cervical carcinoma cells. Cancer Res. 1988 Jul 1;48(13):3780–3786. [PubMed] [Google Scholar]
  36. zur Hausen H. Papillomaviruses in anogenital cancer as a model to understand the role of viruses in human cancers. Cancer Res. 1989 Sep 1;49(17):4677–4681. [PubMed] [Google Scholar]

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