Berkowitz R D, Goff S P
Howard Hughes Medical Institute, Columbia University College of Physicians and Surgeons, New York, New York 10032.
Virology. 1993 Oct;196(2):748-57. doi: 10.1006/viro.1993.1532.
Retroviral envelope proteins are synthesized in the infected cell and targetted to the assembling virion; during infection, they mediate receptor binding and fusion of the virion and cell membranes. We have generated a series of mutants of the Moloney murine leukemia virus (M-MuLV) with alterations in the TM protein, p15E, and determined whether the mutants are defective for replication and where the defects lie. Twenty-one point mutants were assessed for infectivity, virion-associated envelope protein levels, and the ability to confer resistance to superinfection. Only one mutant was specifically defective in a post-receptor binding step. Three other mutants encoded virion-associated envelope proteins that could not confer resistance to superinfection, implying that they could not bind to the receptor. These mutants demonstrate that in M-MuLV, receptor binding and early events such as membrane fusion can be affected by amino acid changes in the TM protein.
逆转录病毒包膜蛋白在受感染细胞中合成，并靶向组装中的病毒体；在感染过程中，它们介导病毒体与细胞膜的受体结合和融合。我们构建了一系列莫洛尼氏鼠白血病病毒（M-MuLV）的突变体，这些突变体的跨膜蛋白p15E发生了改变，并确定了这些突变体在复制方面是否存在缺陷以及缺陷所在位置。对21个点突变体的感染性、病毒体相关包膜蛋白水平以及赋予对超感染抗性的能力进行了评估。只有一个突变体在受体结合后的步骤中存在特异性缺陷。另外三个突变体编码的病毒体相关包膜蛋白不能赋予对超感染的抗性，这意味着它们不能与受体结合。这些突变体表明，在M-MuLV中，受体结合和诸如膜融合等早期事件可受跨膜蛋白中氨基酸变化的影响。
