1887

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Volume 75, Issue 7

Human papillomavirus (HPV) type 18 E7 protein is a short-lived steroid-inducible phosphoprotein in HPV-transformed cell lines Free

Abstract

We used a capture ELISA to quantify the E7 protein of human papillomavirus type 18 (HPV-18). In HeLa cells, which express low levels of immunoreactive E7 protein (iE7), iE7 had a mean half-life of 13·5 min. In HPV-18 E7 recombinant baculovirus (E7rec BV)-infected Sf21 cells, which express higher levels of E7, the half-life of iE7 was much longer (90 min and > 24 h, with two different E7rec BVs). For two transformed human cervical cell lines expressing HPV-18 E7, exposure of the cells to hydrocortisone resulted in a twofold increase in steady-state levels of the E7 protein: no similar effect was observed with progesterone, oestrogen or testosterone. The half-life of iE7 was unaltered by hydrocortisone or progesterone exposure. An immunoassay which distinguished Ser-phosphorylated E7 from E7 not phosphorylated at this residue (Serdephospho-E7), showed that in HeLa and Sf21 cells the majority of E7 was phosphorylated : the half-life of both species of E7 was similar in HeLa cells, but the half-life of Serdephospho-E7 was much shorter (90 min) in Sf21 cells than that of Serphospho-E7 (> 24 h). A HeLa- fibroblast fusion cell line with tumorigenic potential (CGL-1) had a similar ratio of dephospho-E7 to total E7 (0·06), as a similar fusion cell line (CGL-4) with no tumorigenic potential (0·03). We conclude that E7 is a labile phosphoprotein, and that the expression and steady-state level of the E7 protein in eukaryotic cells may be influenced by the hormonal environment of the cells.

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© The Journal of General Virology 1994
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1994-07-01
2024-04-16
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References

  1. Barbosa M. S., Schlegel R. 1989; The E6 and E7 genes of HPV- 18 are sufficient for inducing two-stage in vitro transformation of human keratinocytes. Oncogene 4:1529–1532
     [Google Scholar]
  2. Barbosa M. S., Edmonds C., Fisher C., Schiller J. T., Lowy D. R., Vousden K. H. 1990; The region of the HPV E7 oncoprotein homologous to adenovirus Ela and SV40 large T antigen contains separate domains for Rb binding and casein kinase II phosphorylation. EM BO Journal 9:153–160
     [Google Scholar]
  3. Bedell M. A., Jones K. H., Laimins L. A. 1987; The E6-E7 region of human papillomavirus type 18 is sufficient for transformation of NIH 3T3 and rat-1 cells. Journal of Virology 61:3635–3640
     [Google Scholar]
  4. Bosch F. X., Schwarz E., Boukamp P., Fusenig N. E., Bartsch D., zur Hausen H. 1990; Suppression in vivo of human papillomavirus type 18 E6-E7 gene expression in nontumorigenic HeLa × fibroblast hybrid cells. Journal of Virology 64:4743–4754
     [Google Scholar]
  5. Chan W. K., Klock G., Bernard H. U. 1989; Progesterone and glucocorticoid response elements occur in the long control regions of several human papillomaviruses involved in anogenitalneoplasia. Journal of Virology 63:3261–3269
     [Google Scholar]
  6. Chong T., Chan W.-K., Bernard H. -U. 1990; 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 Research 18:465–470
     [Google Scholar]
  7. Crook T., Morgensuern J. P., Crawford L., Banks L. 1989; Continued expression of HPV-16 E7 protein is required for maintenance of the transformed phenotype of cells co-transformed by HPV-16 plus EJ-ras. EMBO Journal 8:513–519
     [Google Scholar]
  8. Emery V. C., Bishop D. H. L. 1987; The development of multiple expression vectors for high level synthesis of eukaryotic proteins: expression of LCMV-N and AcNPVpolyhedrin protein by a recombinant baculovirus. Protein Engineering 14:359–366
     [Google Scholar]
  9. Frazer I. H., Mackay I. R., Jordan T. W., Whittingham S., Marzuki S. 1985; Reactivity of anti-mitochondrial autoantibodies in primary biliary cirrhosis: definition of two novel mitochondrial polypeptide autoantigens. Journal of Immunology 135:1739–1745
     [Google Scholar]
  10. Grossman S. R., Mora R., Laimins L. A. 1989; Intracellular localization and DNA-binding properties of human papillomavirus type 18 E6 protein expressed with a baculovirus vector. Journal of Virology 63:366–374
     [Google Scholar]
  11. Klock G., Strähle U., Schütz G. 1987; Oestrogen and glucocorticoid responsive elements are closely related but distinct. Nature; London: 329734–736
     [Google Scholar]
  12. Luscher B., Eisenman R. N. 1988; c-myc and c-myb protein degradation: effect of metabolic inhibitors and heat shock. Molecular and Cellular Biology 8:2504–2512
     [Google Scholar]
  13. Münger K., Phelps W. C., Bubb V., Howley P. M., Schlegel R. 1989a; The E6 and E7 genes of the human papillomavirus type 16 together are necessary and sufficient for transformation of primary human keratinocytes. Journal of Virology 63:4417–4421
     [Google Scholar]
  14. Münger K., Werness B. A., Dyson N., Phelps W. C., Harlow E., Howley P. M. 1989b; Complex formation of human papillomavirus E7 proteins with the retinoblastoma tumor suppressor gene product. EM BO Journal 8:4099–4105
     [Google Scholar]
  15. Park D. S., Selvey L. A., Kelsau S. R., Frazer I. H. 1993; Human papillomavirus type 16 E6, E7 and L1 and type 18 E7 proteins produced by recombinant baculoviruses. Journal of Virological Methods 45:303–318
     [Google Scholar]
  16. Pater A., Bayatpour M., Pater M. M. 1990; Oncogenic transformation by human papillomavirus type 16 deoxyribonucleic acid in the presence of progesterone or progestins from oral contraceptives. American Journal of Obstetrics and Gynecology 162:1099–1103
     [Google Scholar]
  17. Pater M. M., Hughes G. A., Hyslop D. E., Nakshatri H., Pater A. 1988; Glucocorticoid-dependent oncogenic transformation by type 16 but not type 11 human papilloma virus DNA. Nature; London: 335832–835
     [Google Scholar]
  18. Peehl D. M., Stanbridge E. J. 1981; Characterisation of human keratinocyte × HeLa somatic cell hybrids. International Journal of Cancer 27:625–635
     [Google Scholar]
  19. Rando R. F., Lindheim S., Hasty L., Sedlacek T. V., Woodland M., Eder C. 1989; Increased frequency of detection of human papillomavirus deoxyribonucleic acid in exfoliated cervical cells during pregnancy. American Journal of Obstetrics and Gynecology 161:50–55
     [Google Scholar]
  20. Ron D., Graziani G., Aaronson S. A., Eva A. 1989; The N-terminal region of proto-dbl down regulates its transforming activity. Oncogene 4:1067–1072
     [Google Scholar]
  21. Schlegel R., Phelps W. C., Zhang Y.-L., Barbosa M. 1988; Quantitative keratinocyte assay detects two biological activities of human papillomavirus DNA and identifies viral types associated with cervical carcinoma. EMBO Journal 7:3181–3187
     [Google Scholar]
  22. Schneider A., Hotz M., Gissmann L. 1987; Increased prevalence of human papillomaviruses in the lower genital tract of pregnant women. International Journal of Cancer 40:198–201
     [Google Scholar]
  23. Schubach W. H., Horvath G. 1988; Alternate structures and stabilities of c-myc RNA in a bursal lymphoma cell line. Nucleic Acids Research 16:11171–11186
     [Google Scholar]
  24. Seedorf K., Oltersdorf T., Krammer G., Rowenkamp W. 1987; Identification of early proteins of the human papillomaviruses type 16 (HPV 16) and type 18 (HPV 18) in cervical carcinoma cells. EMBO Journal 6:139–144
     [Google Scholar]
  25. Selvey L. A., Tindle R. W., Geysen H. M., Haller C. J., Smith J. A., Frazer I. H. 1990; Identification of B-epitopes in the human papillomavirus 18 E7 open reading frame protein. Journal of Immunology 145:3105–3110
     [Google Scholar]
  26. Selvey L. A., Dunn L. A., Murray B., Tindle R. W., Frazer I. H. 1992; An ELISA capture assay for the E7 transforming proteins of HPV16 and HPV18. Journal of Virological Methods 37:119–128
     [Google Scholar]
  27. Smotkin D., Wettstein F. O. 1986; Transcription of human papillomavirus type 16 early genes in a cervical cancer and a cancer- derived cell line and identification of the E7 protein. Proceedings of the National Academy of Sciences, U.S.A 83:4680–4684
     [Google Scholar]
  28. Smotkin D., Wettstein F. O. 1987; The major human papillomavirus protein in cervical cancers is a cytoplasmic phosphoprotein. Journal of Virology 61:1686–1689
     [Google Scholar]
  29. Strähle U., Boshart M., Klock G., Stewart F., Schutz G. 1990; Glucocorticoid- and progesterone-specific effects are determined by differential expression of the respective hormone receptors. Nature; London: 339629–632
     [Google Scholar]
  30. Tindle R. W., Smith J. A., Geysen H. M., Selvey L. A., Frazer I. H. 1990; Identification of B epitopes in human papillomavirus type 16 E7 open reading frame protein. Journal of General Virology 71:1347–1354
     [Google Scholar]
  31. Tratner I., De Togni P., Sassone-Corsi P., Verma I. M. 1990; Characterization and purifiction of human fos protein generated in insect cells with a baculoviral expression vector. Journal of Virology 64:499–508
     [Google Scholar]
  32. Von Knebel Doeberitz M., Oltersdorf T., Schwarz E., Gissmann L. 1988; Correlation of modified human papillomavirus early gene expression with altered growth properties in C4-1 cervical carcinoma cells. Cancer Research 48:3780–3786
     [Google Scholar]
  33. Von Knebel Doeberitz M., Gissmann L., zur Hausen H. 1990; Growth-regulating functions of human papillomavirus early gene products in cervical cancer cells acting dominant over enhanced epidermal growth factor receptor expression. Cancer Research 50:3730–3736
     [Google Scholar]
  34. Von Knebel Doebertiz M., Bauknecht T., Bartsch D., zur Hausen H. 1991; Influence of chromosomal integration on glucocorticoid-regulated transcription of growth-stimulating papil-lomavirus genes E6 and E7 in cervical carcinoma cells. Proceedings of the National Academy of Sciences, U.S.A 88:1411–1415
     [Google Scholar]
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Human papillomavirus (HPV) type 18 E7 protein is a short-lived steroid-inducible phosphoprotein in HPV-transformed cell lines
J. Gen. Virol. 75, 1647 (1994); https://doi.org/10.1099/0022-1317-75-7-1647
/content/journal/jgv/10.1099/0022-1317-75-7-1647
/content/journal/jgv/10.1099/0022-1317-75-7-1647
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