辛德毕斯病毒6K蛋白在病毒成熟释放中的作用

The Effect of 6K Protein of Sindbis Virus on Viral Maturation and Release

应用多种细胞生物学技术,对辛德毕斯病毒(Sindbis Virus,SbV)的6K蛋白在细胞中的分布和转运动态及在病毒释放过程中的作用进行了探讨,结果表明:6K蛋白不仅存在于成熟病毒粒子中,而且在粗面内质网合成后及在向细胞质膜的转运过程中均与囊膜蛋白E2形成复合物。对6K蛋白酰基化位点突变株的研究结果表明,它与E2突变株在病毒形态发生方面有惊人的相似之处,说明SbV的出芽释放过程不仅仅是靠E2蛋白C端与病毒核衣壳的相互作用,6K蛋白的酰基化修饰可能在这个过程中也起着十分重要的作用。根据6K蛋白的二级结构的预测及综合上述实验结果,对SbV出芽释放的模式提出了新的补充。

A small hydrophobic polypeptide of 55 amino acids, noted as the 6K protein, could be detected in purified preparations of Sindbis virions (SbV). 6K proteins become associated to the E2 protein after their cynthesis in the endoplasmic reticulum (ER) and during their transport process from ER to the cell surface. The morphogenetical characteristics of 6K mutant (Cys38→Ser) of SbV with acylation site replacement in the 6K protein showed that the behavior of 6K mutant is very similar to the E2 mu- tant of SbV with amino acid replacement (Ser419-Cys) in the cytoplasmic domain of the E2 protein. It suggests that the release of SbV not only requires specific interaction between cytoplasmic domains of E2 protein and nucleocapsid, but the 6K protein also play an important role. A modified model is pre sented here to demostrate the possible interaction among E2, C and 6K protein of SbV during budding process on the basis of 6K sequences and the results metioned above.