Bernards R, de Leeuw M G, Houweling A, van der Eb A J
Virology. 1986 Apr 15;150(1):126-39. doi: 10.1016/0042-6822(86)90272-2.
We have investigated the contribution of each of the two adenovirus type 5 (Ad5) major early region 1b (E1b) proteins in cell transformation and in lytic infection. An Ad5 E1 plasmid, in which the reading frame for the 19-kDa E1b protein was abolished by a stop codon close to the initiation codon, transformed primary baby rat kidney (BRK) cells with an efficiency of about half of that of a wild type Ad5 E1 plasmid, whereas a plasmid with a mutation in the gene for the 58-kDa E1b protein transformed the same primary cells with only one-third of the wild type efficiency. Plasmids containing region E1a only or a plasmid carrying mutations in the genes for major E1b proteins all transformed primary cells with an efficiency of approximately 5% of wild type. To test the effect of the E1b mutations in virion-mediated cell transformation, the mutant E1b regions were introduced into intact viral genomes by overlap recombination and were subsequently used in a transformation assay on BRK cells. The 19 and 58-kDa mutant viruses were found to transform BRK cells with 11 and 25% of the efficiency of wild type virus, respectively. These results suggest that the 19-kDa E1b protein is essential for virus-mediated cell transformation, in agreement with results of others, but not for plasmid-mediated cell transformation. In lytic infection, the 19-kDa mutant virus was some 30-fold reduced in yield on HeLa cells, whereas the 58-kDa mutant virus was 3000-fold reduced in its ability to grow on HeLa cells at low multiplicity of infection, but showed a marked multiplicity-dependent leakiness. The 58-kDa mutant virus was not defective when its growth was assayed on human embryonic kidney (HEK) cells. This may indicate that cellular proteins are expressed in HEK cells that are functionally homologous to the 58-kDa E1b protein.
我们研究了腺病毒5型（Ad5）主要早期区域1b（E1b）的两种蛋白质在细胞转化和裂解感染中的作用。在一个Ad5 E1质粒中，靠近起始密码子的一个终止密码子使19 kDa E1b蛋白的阅读框被破坏，该质粒转化原代新生大鼠肾（BRK）细胞的效率约为野生型Ad5 E1质粒的一半，而一个58 kDa E1b蛋白基因发生突变的质粒转化相同原代细胞的效率仅为野生型的三分之一。仅含有E1a区域的质粒或携带主要E1b蛋白基因突变的质粒转化原代细胞的效率均约为野生型的5%。为了测试E1b突变在病毒介导的细胞转化中的作用，通过重叠重组将突变的E1b区域引入完整的病毒基因组，随后用于BRK细胞的转化试验。发现19 kDa和58 kDa突变病毒转化BRK细胞的效率分别为野生型病毒的11%和25%。这些结果表明，19 kDa E1b蛋白对于病毒介导的细胞转化是必不可少的，这与其他人的结果一致，但对于质粒介导的细胞转化并非如此。在裂解感染中，19 kDa突变病毒在HeLa细胞上的产量降低了约30倍，而58 kDa突变病毒在低感染复数时在HeLa细胞上生长的能力降低了3000倍，但表现出明显的复数依赖性渗漏。当在人胚肾（HEK）细胞上检测其生长时，58 kDa突变病毒没有缺陷。这可能表明HEK细胞中表达的细胞蛋白在功能上与58 kDa E1b蛋白同源。
