Envelope Proteins of Vesicular Stomatitis Virus: Effect of Temperature-Sensitive Mutations in Complementation Groups III and V
Envelope Proteins of Vesicular Stomatitis Virus: Effect of Temperature-Sensitive Mutations in Complementation Groups III and V
复制标题
水泡性口炎病毒的包膜蛋白：互补组 III 和 V 中温度敏感突变的影响
作者：
F. Lafay
在感染水泡性口炎病毒温度敏感(Ts)互补群III和V突变体的鸡胚细胞中合成了5种主要病毒蛋白，并维持在不允许的温度下。对于野生型和tsIII感染的细胞，这些蛋白在以不连续蔗糖梯度分离的细胞质中的分布是相同的。从感染TSV突变体的细胞中观察到明显不同的G蛋白梯度；即使有，也很少，在最轻的部分中发现G蛋白。对野生型、受病毒感染的细胞进行的脉冲和追逐实验表明，蛋白G在进入病毒粒子之前从最重的部分移动到最轻的部分。在降低到允许的温度(30℃)后，TSV感染细胞在39.6℃合成的G蛋白与最轻的细胞部分相关，随后与释放的病毒粒子相关。相比之下，在感染tsIII的细胞中，在39.6℃下合成的M蛋白在下移后没有被整合到病毒粒子中。这些数据有力地表明，第一，M蛋白是由水泡性口炎基因III编码的，第二，在最轻的细胞组分中掺入G蛋白是水泡性口炎成熟的必要步骤。这一步受到TSV突变的影响。
All five major viral proteins were synthesized in chicken embryo cells infected with vesicular stomatitis virus temperature-sensitive (ts) mutants of complementation groups III and V and maintained at the nonpermissive temperature. The distribution of these proteins among cytoplasmic cellular fractions separated on discontinuous sucrose gradients was identical for wild-type and tsIII-infected cells. Strikingly different patterns were observed for the G protein in gradients from cells infected by tsV mutants; very little, if any, G protein was found in the lightest fraction. Pulse and chase experiments with wild-type, virus-infected cells showed that protein G moves from the heaviest to the lightest fraction before being incorporated into the virion. After shift down to the permissive temperature (30 C), G protein synthesized at 39.6 C in tsV-infected cells became associated with the lightest cellular fraction and later with the released virions. In contrast, M protein, synthesized at 39.6 C in tsIII-infected cells, was not incorporated into the virions after shift down. These data strongly suggest, first, that M protein is encoded by the vesicular stomatitis gene III, and second, that incorporation of G protein in the lightest cellular fraction is a necessary step of vesicular stomatitis maturation. This step is impaired by tsV mutations.