标题：Localization of bovine papillomavirus type 1 E5 protein to transformed basal keratinocytes and permissive differentiated cells in fibropapilloma tissue.
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1992
卷号：89
期号：12
页码：5665-5669
DOI：10.1073/pnas.89.12.5665
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：We examined expression of the E5 transforming protein of bovine papillomavirus type 1 (BPV-1) in naturally and experimentally infected bovine cells. Bovine conjunctival fibroblasts transformed in vitro by experimental infection with purified BPV-1 virions expressed significantly higher amounts of the 7-kDa E5 protein than BPV-1-transformed murine C127 cells. Indirect immunofluourescence analysis revealed a cytoplasmic, predominantly juxtanuclear, localization of E5 protein in the in vitro virus-transformed bovine cells. In naturally infected bovine skin fibropapilloma tissue, two widely separated sites of E5 protein synthesis were identified within the epithelial layers. Transformed basal layer keratinocytes throughout the tumor tissue expressed cytoplasmic E5 protein at a low uniform level. In addition, abundant amounts of cytoplasmic E5 protein with a granular staining pattern were detected in highly differentiated keratinocytes in close association with sites of viral capsid protein synthesis. These observations imply roles for the viral E5 oncogene in the growth transformation of basal epidermal keratinocytes as well as in the differentiation-linked process of viral maturation. Detection of a papillomavirus protein in the basal cell population of warts lends support to the hypothesis that these cells are maintained in a transformed state by continuous expression of a viral transforming gene.
