Buchschacher G L, Freed E O, Panganiban A T
McArdle Laboratory for Cancer Research, University of Wisconsin, Madison 53706.
J Virol. 1995 Feb;69(2):1344-8. doi: 10.1128/JVI.69.2.1344-1348.1995.
We have demonstrated previously that a human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein containing a Val-to-Glu substitution at the second amino acid of the transmembrane glycoprotein gp41 (termed the 41.2 mutant) dominantly interferes with wild-type envelope-mediated syncytium formation and virus infectivity. To understand the mechanism by which the 41.2 mutant exerts the dominant interfering phenotype and thereby determine further how the mutant might be used as an inhibitor of viral spread, additional mutations were made in the envelope gene, and the effects of these mutations on interference were determined. It was found that processing of the 41.2 mutant glycoprotein in gp120 and gp41 subunits and a functional CD4-binding domain are necessary for the interfering phenotype to be exhibited fully. However, neither a wild-type V3 loop nor the gp41 cytoplasmic tail is necessary for efficient interference. In addition, it was determined that the dominant interfering phenotype is not conferred exclusively by the glutamate substitution at amino acid 2 of gp41, since a substitution with a basic residue at this position also results in a dominant interfering envelope glycoprotein.
我们之前已经证明，一种在跨膜糖蛋白gp41的第二个氨基酸处含有缬氨酸到谷氨酸替换的1型人类免疫缺陷病毒（HIV-1）包膜糖蛋白（称为41.2突变体），可显著干扰野生型包膜介导的合胞体形成和病毒感染性。为了理解41.2突变体发挥显性干扰表型的机制，并进而确定该突变体如何用作病毒传播的抑制剂，我们在包膜基因中引入了其他突变，并确定了这些突变对干扰作用的影响。结果发现，41.2突变体糖蛋白在gp120和gp41亚基中的加工以及功能性CD4结合结构域对于充分展现干扰表型是必需的。然而，有效的干扰既不需要野生型V3环，也不需要gp41胞质尾巴。此外，还确定显性干扰表型并非仅由gp41第2位氨基酸的谷氨酸替换所赋予，因为在此位置用碱性残基进行替换也会产生显性干扰性包膜糖蛋白。
