Hallenberger S, Tucker S P, Owens R J, Bernstein H B, Compans R W
Department of Microbiology, University of Alabama, Birmingham 35294.
Virology. 1993 Mar;193(1):510-4. doi: 10.1006/viro.1993.1156.
We have characterized a truncated secreted form of the HIV-1 envelope glycoprotein gene. Expression via a recombinant vaccinia virus resulted in a glycoprotein product of approximately 140 kDa (gp160t) and a minor cleavage product of 120 kDa (gp120). Pulse-chase analysis revealed that the majority of gp160t remained cell-associated and underwent degradation within 10-20 hr of synthesis. A secreted form (gp160t/sec) and gp120 were detected in the media 2-4 hr postsynthesis and were not significantly degraded within a period of 20 hr. Most of the cell-associated gp160t remained sensitive to digestion with endoglycosidase H, whereas gp160t/sec and gp120 were largely resistant. Gp160t, gp160t/sec, and gp120 formed oligomers which were stabilized by intermolecular disulfide bonds and/or noncovalent interactions and were also found to bind to soluble CD4. Both wild type gp160 and wild type gp160t were observed to undergo a post-translational modification 4-5 hr postsynthesis, resulting in glycoproteins with a slightly increased electrophoretic mobility. These differences in electrophoretic mobility remained following treatment with N-glycosidase F, indicating that they are not a consequence of N-linked oligosaccharide processing, but may represent an additional modification of the envelope glycoprotein.
我们已对HIV-1包膜糖蛋白基因的一种截短的分泌形式进行了表征。通过重组痘苗病毒表达产生了一种约140 kDa的糖蛋白产物（gp160t）和一种120 kDa的小裂解产物（gp120）。脉冲追踪分析表明，大多数gp160t仍与细胞相关，并在合成后10 - 20小时内发生降解。在合成后2 - 4小时在培养基中检测到一种分泌形式（gp160t/sec）和gp120，并且在20小时内未发生明显降解。大多数与细胞相关的gp160t对内切糖苷酶H的消化仍敏感，而gp160t/sec和gp120大多具有抗性。Gp160t、gp160t/sec和gp120形成寡聚体，这些寡聚体通过分子间二硫键和/或非共价相互作用得以稳定，并且还发现它们能与可溶性CD4结合。野生型gp160和野生型gp160t在合成后4 - 5小时均观察到发生了翻译后修饰，产生了电泳迁移率略有增加的糖蛋白。用N-糖苷酶F处理后，这些电泳迁移率的差异仍然存在，表明它们不是N-连接寡糖加工的结果，而是可能代表包膜糖蛋白的一种额外修饰。
