Heck D V, Yee C L, Howley P M, Münger K
Laboratory of Tumor Virus Biology, National Cancer Institute, Bethesda, MD 20892.
Proc Natl Acad Sci U S A. 1992 May 15;89(10):4442-6. doi: 10.1073/pnas.89.10.4442.
The human papillomaviruses (HPVs) associated with genital tract lesions can be classified as either "high risk" or "low risk" based on their association with human anogenital cancer. The E7 proteins of the high-risk and the low-risk viruses are quite similar in their amino acid composition and structural organization yet differ in their transforming potential and in a number of biochemical properties. A series of chimeric proteins consisting of segments of the high-risk HPV-16 and the low-risk HPV-6 E7 proteins were constructed in order to define which domains within the amino-terminal half of E7 were responsible for the different biological and biochemical properties. The E7 oncogenic capacity, which was determined by assaying transformation of baby rat kidney cells in cooperation with an activated ras oncogene, segregated with the retinoblastoma tumor suppressor protein (pRB) binding domain of the HPV-16 E7 protein. A comparison of the pRB binding sites of the sequenced genital tract HPVs revealed a consistent amino acid difference (aspartic acid/glycine) between the high-risk and low-risk viruses. Single amino acid substitution mutations were generated at this position in the HPV-6 and HPV-16 E7 proteins, and this single amino acid residue was shown to be the principal determinant responsible for the differences in the apparent pRB binding affinity and transformation capacity distinguishing the HPV E7 proteins of the high-risk and low-risk HPVs.
与生殖道病变相关的人乳头瘤病毒（HPV）可根据其与人类肛门生殖器癌的关联分为“高危”或“低危”。高危和低危病毒的E7蛋白在氨基酸组成和结构组织上非常相似，但在转化潜能和一些生化特性方面存在差异。构建了一系列由高危HPV - 16和低危HPV - 6 E7蛋白片段组成的嵌合蛋白，以确定E7蛋白氨基末端一半内的哪些结构域导致了不同的生物学和生化特性。通过检测与激活的ras癌基因协同作用下对幼鼠肾细胞的转化来确定的E7致癌能力，与HPV - 16 E7蛋白的视网膜母细胞瘤肿瘤抑制蛋白（pRB）结合结构域相关。对已测序的生殖道HPV的pRB结合位点进行比较发现，高危和低危病毒之间存在一致的氨基酸差异（天冬氨酸/甘氨酸）。在HPV - 6和HPV - 16 E7蛋白的该位置产生了单氨基酸取代突变，并且该单氨基酸残基被证明是区分高危和低危HPV的HPV E7蛋白在表观pRB结合亲和力和转化能力方面差异的主要决定因素。
