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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. 总被引:11,自引:7,他引:4 下载免费PDF全文
S A Sedman M S Barbosa W C Vass N L Hubbert J A Haas D R Lowy J T Schiller 《Journal of virology》1991,65(9):4860-4866
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Involvement of human papillomavirus type 8 genes E6 and E7 in transformation and replication. 总被引:10,自引:6,他引:4 下载免费PDF全文
We investigated the transforming activity of human papillomavirus type 8 (HPV8) by expressing all early open reading frames from a heterologous promoter in different rodent fibroblast lines. Morphological transformation was observed only in G418-selected mouse C127 and Rat 1 cells containing an intact E6-coding region. E6 of HPV8 did not transform NIH 3T3 cells as did E6 of bovine papillomavirus type 1. C127 cells transformed by E6 were anchorage independent and had a reduced serum requirement but did not form tumors in nude mice. E7 of HPV8 showed no transforming potential, in contrast to E7 of HPV18 and HPV16. It was, however, able to complement an E7 mutant of bovine papillomavirus type 1 with a defect in high-copy-number DNA maintenance. The data indicate that the expression of the HPV8 E6 open reading frame is sufficient to induce morphological transformation in rodent fibroblasts, whereas E7 is involved in the replication of the viral DNA. 相似文献
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HPV16 E6 and E7 proteins cooperate to immortalize human foreskin keratinocytes. 总被引:111,自引:11,他引:100 下载免费PDF全文
P Hawley-Nelson K H Vousden N L Hubbert D R Lowy J T Schiller 《The EMBO journal》1989,8(12):3905-3910
The human papillomavirus types (HPVs) most often associated with cancer of the cervix, such as HPV16, have been reported previously to immortalize normal human foreskin keratinocytes in vitro, while the types that are primarily associated with benign cervical lesions failed to do so. In this study we have determined the HPV16 genes that are responsible for the immortalizing activity of the viral genome. Transfection with a plasmid in which E6 and E7 were the only intact open reading frames (ORFs) induced an indefinite life-span in the keratinocytes with an efficiency similar to that of the entire early region of the viral DNA. Mutants in the E6E7 clone with inactivating lesions in E6 or E7 failed to induce immortalization. When transfected alone, E7 could induce hyperproliferation, but these cells eventually senesced. By itself, E6 exhibited no activity, Co-transfection of a plasmid with an intact E6 ORF and a second plasmid with an intact E7 ORF generated keratinocyte lines with indefinite growth potential. The E6 and E7 proteins were detected in the lines induced by the E6E7 DNA and by co-transfection of the E6 and E7 plasmids. Therefore, we conclude that HPV16 E6 and E7 cooperative to immortalize human keratinocytes in vitro. Changes in cellular gene expression are probably also required for immortalization since all of the keratinocyte lines examined were aneuploid. Serum and calcium resistant sublines were isolated from the E6E7 induced lines, indicating that other HPV genes do not play an obligatory role in the generation of resistance to differentiation.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
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The E7 gene of human papillomavirus type 16 is sufficient for immortalization of human epithelial cells. 总被引:49,自引:23,他引:26 下载免费PDF全文
The contribution of the E6 and E7 open reading frames of human papillomavirus type 6b (HPV6b) and HPV16 to immortalization of human keratinocytes was evaluated by using amphotropic recombinant retroviruses. The HPV16 E7 gene could immortalize primary human keratinocytes without the cooperation of the viral E6 gene; however, E6 was able to contribute significantly to the efficiency of the E7 immortalizing function. Infection of HFE cells with retroviruses carrying the 16E6, 6bE6, or 6bE6E7 open reading frame did not result in immortalization. 相似文献
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Human papillomavirus type 18 E6*, E6, and E7 protein synthesis in cell-free translation systems and comparison of E6 and E7 in vitro translation products to proteins immunoprecipitated from human epithelial cells. 下载免费PDF全文
B Roggenbuck P M Larsen S J Fey D Bartsch L Gissmann E Schwarz 《Journal of virology》1991,65(9):5068-5072
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Identification of human papillomavirus type 18 transforming genes in immortalized and primary cells. 总被引:35,自引:17,他引:18 下载免费PDF全文
The selective retention and expression of the E6-E7 region of human papillomavirus (HPV) types 16 and 18 in cervical carcinomas suggests that these viral sequences play a role in the development of genital neoplasia. Each of three possible gene products, E6, E6*, and E7, from this region of HPV-18 were examined for transforming properties in several types of rodent cells. We have found that in immortalized fibroblasts, both E6 and E7 (but not E6*) are capable of inducing anchorage-independent growth. In rat embryo cells, the HPV-18 E7 open reading frame was an effective immortalizing agent and complemented an activated ras oncogene for transformation. In both immortalized and primary cells, transformation was observed when the HPV-18 sequences were expressed from either the HPV-18 promoter or a heterologous promoter. The E6-E7 region is not, however, the sole transforming domain of HPV-18, since another portion of the early region, possibly E5, also exhibited transforming capability in immortalized fibroblasts. The development of human cervical carcinomas may therefore involve a series of steps involving multiple viral and cellular gene products. 相似文献
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Immortalization and altered differentiation of human keratinocytes in vitro by the E6 and E7 open reading frames of human papillomavirus type 18. 总被引:49,自引:30,他引:19 下载免费PDF全文
The E6-E7 region of human papillomavirus types 16 and 18 is selectively retained and expressed in cervical carcinoma cells. In cultured human keratinocytes, expression of the E6 and E7 open reading frames of human papillomavirus type 18, under the control of its homologous promoter, resulted in high-frequency immortalization. Furthermore, by using a system that allows for stratification of keratinocytes in vitro (raft system), we observed that the morphological differentiation of these E6-E7 immortalized cells was altered such that parabasal cells extended throughout most of the epithelium, with abnormal nuclei present in the upper regions. Examination of E6-E7-expressing cell lines in the raft system at a later passage revealed that complete loss of morphological differentiation had occurred. E7 alone was a much less effective immortalizing agent than E6 and E7 together and acted only minimally to alter morphological differentiation in vitro. No such activities were found for E6 alone. High-frequency transformation of human epithelial cells thus appears to require expression of both E6 and E7 gene products. 相似文献