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. 1996 Nov;70(11):7549–7560. doi: 10.1128/jvi.70.11.7549-7560.1996

Enhanced transcriptional activation by E2 proteins from the oncogenic human papillomaviruses.

R Kovelman 1, G K Bilter 1, E Glezer 1, A Y Tsou 1, M S Barbosa 1
PMCID: PMC190823  PMID: 8892874

Abstract

A systematic comparison of transcriptional activation by papillomavirus E2 proteins revealed that the E2 proteins from high-risk human papillomaviruses (human papillomavirus type 16 [HPV-16] and HPV-18) are much more active than are the E2 proteins from low-risk HPVs (HPV-6b and HPV-11). Despite the tropism of HPVs for particular epithelial cell types, this difference in transcriptional activation was observed in a number of different epithelial and nonepithelial cells. The enhanced activities of the E2 proteins from high-risk HPVs did not result from higher steady-state levels of protein in vivo, and in vitro DNA-binding assays revealed similar binding properties for these two classes of E2 proteins. These results demonstrate that the E2 proteins from high-risk HPVs have an intrinsically enhanced potential to activate transcription from promoters with E2-responsive elements. We found that there are also substantial differences between the activation properties of the bovine papillomavirus type 1 E2 protein and those of either of the two classes of HPV E2 proteins, especially with regard to requirements for particular configurations of E2 binding sites in the target promoter. Our results indicate that there are at least three distinct functional classes of E2 proteins and that these classes of E2 proteins may perform different roles during the respective viral life cycles.

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Selected References

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  1. Androphy E. J., Lowy D. R., Schiller J. T. Bovine papillomavirus E2 trans-activating gene product binds to specific sites in papillomavirus DNA. Nature. 1987 Jan 1;325(6099):70–73. doi: 10.1038/325070a0. [DOI] [PubMed] [Google Scholar]
  2. Barbosa M. S., Schlegel R. The E6 and E7 genes of HPV-18 are sufficient for inducing two-stage in vitro transformation of human keratinocytes. Oncogene. 1989 Dec;4(12):1529–1532. [PubMed] [Google Scholar]
  3. 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]
  4. Bedrosian C. L., Bastia D. The DNA-binding domain of HPV-16 E2 protein interaction with the viral enhancer: protein-induced DNA bending and role of the nonconserved core sequence in binding site affinity. Virology. 1990 Feb;174(2):557–575. doi: 10.1016/0042-6822(90)90109-5. [DOI] [PubMed] [Google Scholar]
  5. Bernard B. A., Bailly C., Lenoir M. C., Darmon M., Thierry F., Yaniv M. The human papillomavirus type 18 (HPV18) E2 gene product is a repressor of the HPV18 regulatory region in human keratinocytes. J Virol. 1989 Oct;63(10):4317–4324. doi: 10.1128/jvi.63.10.4317-4324.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Bouvard V., Storey A., Pim D., Banks L. Characterization of the human papillomavirus E2 protein: evidence of trans-activation and trans-repression in cervical keratinocytes. EMBO J. 1994 Nov 15;13(22):5451–5459. doi: 10.1002/j.1460-2075.1994.tb06880.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Brewer C. B., Roth M. G. A single amino acid change in the cytoplasmic domain alters the polarized delivery of influenza virus hemagglutinin. J Cell Biol. 1991 Aug;114(3):413–421. doi: 10.1083/jcb.114.3.413. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Chiang C. M., Ustav M., Stenlund A., Ho T. F., Broker T. R., Chow L. T. Viral E1 and E2 proteins support replication of homologous and heterologous papillomaviral origins. Proc Natl Acad Sci U S A. 1992 Jul 1;89(13):5799–5803. doi: 10.1073/pnas.89.13.5799. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Chin M. T., Hirochika R., Hirochika H., Broker T. R., Chow L. T. Regulation of human papillomavirus type 11 enhancer and E6 promoter by activating and repressing proteins from the E2 open reading frame: functional and biochemical studies. J Virol. 1988 Aug;62(8):2994–3002. doi: 10.1128/jvi.62.8.2994-3002.1988. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Choe J., Vaillancourt P., Stenlund A., Botchan M. Bovine papillomavirus type 1 encodes two forms of a transcriptional repressor: structural and functional analysis of new viral cDNAs. J Virol. 1989 Apr;63(4):1743–1755. doi: 10.1128/jvi.63.4.1743-1755.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Chow L. T., Nasseri M., Wolinsky S. M., Broker T. R. Human papillomavirus types 6 and 11 mRNAs from genital condylomata acuminata. J Virol. 1987 Aug;61(8):2581–2588. doi: 10.1128/jvi.61.8.2581-2588.1987. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. 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]
  13. Cripe T. P., Haugen T. H., Turk J. P., Tabatabai F., Schmid P. G., 3rd, Dürst M., Gissmann L., Roman A., Turek L. P. Transcriptional regulation of the human papillomavirus-16 E6-E7 promoter by a keratinocyte-dependent enhancer, and by viral E2 trans-activator and repressor gene products: implications for cervical carcinogenesis. EMBO J. 1987 Dec 1;6(12):3745–3753. doi: 10.1002/j.1460-2075.1987.tb02709.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Del Vecchio A. M., Romanczuk H., Howley P. M., Baker C. C. Transient replication of human papillomavirus DNAs. J Virol. 1992 Oct;66(10):5949–5958. doi: 10.1128/jvi.66.10.5949-5958.1992. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Dostatni N., Lambert P. F., Sousa R., Ham J., Howley P. M., Yaniv M. The functional BPV-1 E2 trans-activating protein can act as a repressor by preventing formation of the initiation complex. Genes Dev. 1991 Sep;5(9):1657–1671. doi: 10.1101/gad.5.9.1657. [DOI] [PubMed] [Google Scholar]
  16. Gauthier J. M., Dostatni N., Lusky M., Yaniv M. Two DNA-bound E2 dimers are required for strong transcriptional activation and for cooperation with cellular factors in most cells. New Biol. 1991 May;3(5):498–509. [PubMed] [Google Scholar]
  17. Giri I., Yaniv M. Structural and mutational analysis of E2 trans-activating proteins of papillomaviruses reveals three distinct functional domains. EMBO J. 1988 Sep;7(9):2823–2829. doi: 10.1002/j.1460-2075.1988.tb03138.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Giri I., Yaniv M. Study of the E2 gene product of the cottontail rabbit papillomavirus reveals a common mechanism of transactivation among papillomaviruses. J Virol. 1988 May;62(5):1573–1581. doi: 10.1128/jvi.62.5.1573-1581.1988. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Gopalakrishnan V., Khan S. A. E1 protein of human papillomavirus type 1a is sufficient for initiation of viral DNA replication. Proc Natl Acad Sci U S A. 1994 Sep 27;91(20):9597–9601. doi: 10.1073/pnas.91.20.9597. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Grossel M. J., Sverdrup F., Breiding D. E., Androphy E. J. Transcriptional activation function is not required for stimulation of DNA replication by bovine papillomavirus type 1 E2. J Virol. 1996 Oct;70(10):7264–7269. doi: 10.1128/jvi.70.10.7264-7269.1996. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Guan K. L., Dixon J. E. Eukaryotic proteins expressed in Escherichia coli: an improved thrombin cleavage and purification procedure of fusion proteins with glutathione S-transferase. Anal Biochem. 1991 Feb 1;192(2):262–267. doi: 10.1016/0003-2697(91)90534-z. [DOI] [PubMed] [Google Scholar]
  22. 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]
  23. Ham J., Dostatni N., Gauthier J. M., Yaniv M. The papillomavirus E2 protein: a factor with many talents. Trends Biochem Sci. 1991 Nov;16(11):440–444. doi: 10.1016/0968-0004(91)90172-r. [DOI] [PubMed] [Google Scholar]
  24. Ham J., Steger G., Yaniv M. Cooperativity in vivo between the E2 transactivator and the TATA box binding protein depends on core promoter structure. EMBO J. 1994 Jan 1;13(1):147–157. doi: 10.1002/j.1460-2075.1994.tb06244.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Haugen T. H., Cripe T. P., Ginder G. D., Karin M., Turek L. P. Trans-activation of an upstream early gene promoter of bovine papilloma virus-1 by a product of the viral E2 gene. EMBO J. 1987 Jan;6(1):145–152. doi: 10.1002/j.1460-2075.1987.tb04732.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  26. Haugen T. H., Turek L. P., Mercurio F. M., Cripe T. P., Olson B. J., Anderson R. D., Seidl D., Karin M., Schiller J. Sequence-specific and general transcriptional activation by the bovine papillomavirus-1 E2 trans-activator require an N-terminal amphipathic helix-containing E2 domain. EMBO J. 1988 Dec 20;7(13):4245–4253. doi: 10.1002/j.1460-2075.1988.tb03322.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  27. Hawley-Nelson P., Androphy E. J., Lowy D. R., Schiller J. T. The specific DNA recognition sequence of the bovine papillomavirus E2 protein is an E2-dependent enhancer. EMBO J. 1988 Feb;7(2):525–531. doi: 10.1002/j.1460-2075.1988.tb02841.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  28. Hermonat P. L., Spalholz B. A., Howley P. M. The bovine papillomavirus P2443 promoter is E2 trans-responsive: evidence for E2 autoregulation. EMBO J. 1988 Sep;7(9):2815–2822. doi: 10.1002/j.1460-2075.1988.tb03137.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  29. Hirochika H., Broker T. R., Chow L. T. Enhancers and trans-acting E2 transcriptional factors of papillomaviruses. J Virol. 1987 Aug;61(8):2599–2606. doi: 10.1128/jvi.61.8.2599-2606.1987. [DOI] [PMC free article] [PubMed] [Google Scholar]
  30. Hirochika H., Hirochika R., Broker T. R., Chow L. T. Functional mapping of the human papillomavirus type 11 transcriptional enhancer and its interaction with the trans-acting E2 proteins. Genes Dev. 1988 Jan;2(1):54–67. doi: 10.1101/gad.2.1.54. [DOI] [PubMed] [Google Scholar]
  31. Hubbert N. L., Schiller J. T., Lowy D. R., Androphy E. J. Bovine papilloma virus-transformed cells contain multiple E2 proteins. Proc Natl Acad Sci U S A. 1988 Aug;85(16):5864–5868. doi: 10.1073/pnas.85.16.5864. [DOI] [PMC free article] [PubMed] [Google Scholar]
  32. Hummel M., Hudson J. B., Laimins L. A. Differentiation-induced and constitutive transcription of human papillomavirus type 31b in cell lines containing viral episomes. J Virol. 1992 Oct;66(10):6070–6080. doi: 10.1128/jvi.66.10.6070-6080.1992. [DOI] [PMC free article] [PubMed] [Google Scholar]
  33. Lambert P. F., Hubbert N. L., Howley P. M., Schiller J. T. Genetic assignment of multiple E2 gene products in bovine papillomavirus-transformed cells. J Virol. 1989 Jul;63(7):3151–3154. doi: 10.1128/jvi.63.7.3151-3154.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
  34. Lambert P. F., Spalholz B. A., Howley P. M. A transcriptional repressor encoded by BPV-1 shares a common carboxy-terminal domain with the E2 transactivator. Cell. 1987 Jul 3;50(1):69–78. doi: 10.1016/0092-8674(87)90663-5. [DOI] [PubMed] [Google Scholar]
  35. 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]
  36. McBride A. A., Romanczuk H., Howley P. M. The papillomavirus E2 regulatory proteins. J Biol Chem. 1991 Oct 5;266(28):18411–18414. [PubMed] [Google Scholar]
  37. McBride A. A., Schlegel R., Howley P. M. The carboxy-terminal domain shared by the bovine papillomavirus E2 transactivator and repressor proteins contains a specific DNA binding activity. EMBO J. 1988 Feb;7(2):533–539. doi: 10.1002/j.1460-2075.1988.tb02842.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  38. Morrissey L. C., Barsoum J., Androphy E. J. Trans activation by the bovine papillomavirus E2 protein in Saccharomyces cerevisiae. J Virol. 1989 Oct;63(10):4422–4425. doi: 10.1128/jvi.63.10.4422-4425.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
  39. Moskaluk C. A., Bastia D. Interaction of the bovine papillomavirus type 1 E2 transcriptional control protein with the viral enhancer: purification of the DNA-binding domain and analysis of its contact points with DNA. J Virol. 1988 Jun;62(6):1925–1931. doi: 10.1128/jvi.62.6.1925-1931.1988. [DOI] [PMC free article] [PubMed] [Google Scholar]
  40. Phelps W. C., Howley P. M. Transcriptional trans-activation by the human papillomavirus type 16 E2 gene product. J Virol. 1987 May;61(5):1630–1638. doi: 10.1128/jvi.61.5.1630-1638.1987. [DOI] [PMC free article] [PubMed] [Google Scholar]
  41. Prakash S. S., Horwitz B. H., Zibello T., Settleman J., DiMaio D. Bovine papillomavirus E2 gene regulates expression of the viral E5 transforming gene. J Virol. 1988 Oct;62(10):3608–3613. doi: 10.1128/jvi.62.10.3608-3613.1988. [DOI] [PMC free article] [PubMed] [Google Scholar]
  42. Ptashne M. How eukaryotic transcriptional activators work. Nature. 1988 Oct 20;335(6192):683–689. doi: 10.1038/335683a0. [DOI] [PubMed] [Google Scholar]
  43. Rank N. M., Lambert P. F. Bovine papillomavirus type 1 E2 transcriptional regulators directly bind two cellular transcription factors, TFIID and TFIIB. J Virol. 1995 Oct;69(10):6323–6334. doi: 10.1128/jvi.69.10.6323-6334.1995. [DOI] [PMC free article] [PubMed] [Google Scholar]
  44. Romanczuk H., Thierry F., Howley P. M. Mutational analysis of cis elements involved in E2 modulation of human papillomavirus type 16 P97 and type 18 P105 promoters. J Virol. 1990 Jun;64(6):2849–2859. doi: 10.1128/jvi.64.6.2849-2859.1990. [DOI] [PMC free article] [PubMed] [Google Scholar]
  45. Scheffner M., Münger K., Byrne J. C., Howley P. M. The state of the p53 and retinoblastoma genes in human cervical carcinoma cell lines. Proc Natl Acad Sci U S A. 1991 Jul 1;88(13):5523–5527. doi: 10.1073/pnas.88.13.5523. [DOI] [PMC free article] [PubMed] [Google Scholar]
  46. 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]
  47. Sedman S. A., Barbosa M. S., Vass W. C., Hubbert N. L., Haas J. A., Lowy D. R., Schiller J. T. The full-length E6 protein of human papillomavirus type 16 has transforming and trans-activating activities and cooperates with E7 to immortalize keratinocytes in culture. J Virol. 1991 Sep;65(9):4860–4866. doi: 10.1128/jvi.65.9.4860-4866.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
  48. Seedorf K., Krämmer G., Dürst M., Suhai S., Röwekamp W. G. Human papillomavirus type 16 DNA sequence. Virology. 1985 Aug;145(1):181–185. doi: 10.1016/0042-6822(85)90214-4. [DOI] [PubMed] [Google Scholar]
  49. Smith D. B., Johnson K. S. Single-step purification of polypeptides expressed in Escherichia coli as fusions with glutathione S-transferase. Gene. 1988 Jul 15;67(1):31–40. doi: 10.1016/0378-1119(88)90005-4. [DOI] [PubMed] [Google Scholar]
  50. Smotkin D., Prokoph H., Wettstein F. O. Oncogenic and nononcogenic human genital papillomaviruses generate the E7 mRNA by different mechanisms. J Virol. 1989 Mar;63(3):1441–1447. doi: 10.1128/jvi.63.3.1441-1447.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
  51. Smotkin D., Wettstein F. O. Transcription of human papillomavirus type 16 early genes in a cervical cancer and a cancer-derived cell line and identification of the E7 protein. Proc Natl Acad Sci U S A. 1986 Jul;83(13):4680–4684. doi: 10.1073/pnas.83.13.4680. [DOI] [PMC free article] [PubMed] [Google Scholar]
  52. Spalholz B. A., Byrne J. C., Howley P. M. Evidence for cooperativity between E2 binding sites in E2 trans-regulation of bovine papillomavirus type 1. J Virol. 1988 Sep;62(9):3143–3150. doi: 10.1128/jvi.62.9.3143-3150.1988. [DOI] [PMC free article] [PubMed] [Google Scholar]
  53. Steger G., Ham J., Lefebvre O., Yaniv M. The bovine papillomavirus 1 E2 protein contains two activation domains: one that interacts with TBP and another that functions after TBP binding. EMBO J. 1995 Jan 16;14(2):329–340. doi: 10.1002/j.1460-2075.1995.tb07007.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  54. Stenlund A., Botchan M. R. The E2 trans-activator can act as a repressor by interfering with a cellular transcription factor. Genes Dev. 1990 Jan;4(1):123–136. doi: 10.1101/gad.4.1.123. [DOI] [PubMed] [Google Scholar]
  55. Stoler M. H., Wolinsky S. M., Whitbeck A., Broker T. R., Chow L. T. Differentiation-linked human papillomavirus types 6 and 11 transcription in genital condylomata revealed by in situ hybridization with message-specific RNA probes. Virology. 1989 Sep;172(1):331–340. doi: 10.1016/0042-6822(89)90135-9. [DOI] [PubMed] [Google Scholar]
  56. Storey A., Osborn K., Crawford L. Co-transformation by human papillomavirus types 6 and 11. J Gen Virol. 1990 Jan;71(Pt 1):165–171. doi: 10.1099/0022-1317-71-1-165. [DOI] [PubMed] [Google Scholar]
  57. Sverdrup F., Khan S. A. Replication of human papillomavirus (HPV) DNAs supported by the HPV type 18 E1 and E2 proteins. J Virol. 1994 Jan;68(1):505–509. doi: 10.1128/jvi.68.1.505-509.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
  58. Thierry F., Heard J. M., Dartmann K., Yaniv M. Characterization of a transcriptional promoter of human papillomavirus 18 and modulation of its expression by simian virus 40 and adenovirus early antigens. J Virol. 1987 Jan;61(1):134–142. doi: 10.1128/jvi.61.1.134-142.1987. [DOI] [PMC free article] [PubMed] [Google Scholar]
  59. Thierry F., Howley P. M. Functional analysis of E2-mediated repression of the HPV18 P105 promoter. New Biol. 1991 Jan;3(1):90–100. [PubMed] [Google Scholar]
  60. Thierry F., Yaniv M. The BPV1-E2 trans-acting protein can be either an activator or a repressor of the HPV18 regulatory region. EMBO J. 1987 Nov;6(11):3391–3397. doi: 10.1002/j.1460-2075.1987.tb02662.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  61. Ushikai M., Lace M. J., Yamakawa Y., Kono M., Anson J., Ishiji T., Parkkinen S., Wicker N., Valentine M. E., Davidson I. trans activation by the full-length E2 proteins of human papillomavirus type 16 and bovine papillomavirus type 1 in vitro and in vivo: cooperation with activation domains of cellular transcription factors. J Virol. 1994 Oct;68(10):6655–6666. doi: 10.1128/jvi.68.10.6655-6666.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
  62. Vande Pol S. B., Howley P. M. A bovine papillomavirus constitutive enhancer is negatively regulated by the E2 repressor through competitive binding for a cellular factor. J Virol. 1990 Nov;64(11):5420–5429. doi: 10.1128/jvi.64.11.5420-5429.1990. [DOI] [PMC free article] [PubMed] [Google Scholar]
  63. zur Hausen H. Human papillomaviruses in the pathogenesis of anogenital cancer. Virology. 1991 Sep;184(1):9–13. doi: 10.1016/0042-6822(91)90816-t. [DOI] [PubMed] [Google Scholar]

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