Jia X Y, Van Eden M, Busch M G, Ehrenfeld E, Summers D F
Departments of Microbiology and Molecular Genetics, University of California, Irvine, California 92697, USA.
J Virol. 1998 Oct;72(10):7972-7. doi: 10.1128/JVI.72.10.7972-7977.1998.
A trans-encapsidation assay was established to study the specificity of picornavirus RNA encapsidation. A poliovirus replicon with the luciferase gene replacing the capsid protein-coding region was coexpressed in transfected HeLa cells with capsid proteins from homologous or heterologous virus. Successful trans-encapsidation resulted in assembly and production of virions whose replication, upon subsequent infection of HeLa cells, was accompanied by expression of luciferase activity. The amount of luciferase activity was proportional to the amount of trans-encapsidated virus produced from the cotransfection. When poliovirus capsid proteins were supplied in trans, >2 x 10(6) infectious particles/ml were produced. When coxsackievirus B3, human rhinovirus 14, mengovirus, or hepatitis A virus (HAV) capsid proteins were supplied in trans, all but HAV showed some encapsidation of the replicon. The overall encapsidation efficiency of the replicon RNA by heterologous capsid proteins was significantly lower than when poliovirus capsid was used. trans-encapsidated particles could be completely neutralized with specific antisera against each of the donor virus capsids. The results indicate that encapsidation is regulated by specific viral nucleic acid and protein sequences.
建立了一种转衣壳化试验来研究小RNA病毒RNA衣壳化的特异性。将一个用荧光素酶基因取代衣壳蛋白编码区的脊髓灰质炎病毒复制子与来自同源或异源病毒的衣壳蛋白在转染的HeLa细胞中共表达。成功的转衣壳化导致病毒粒子的组装和产生，其在随后感染HeLa细胞时的复制伴随着荧光素酶活性的表达。荧光素酶活性的量与共转染产生的转衣壳化病毒的量成正比。当以反式提供脊髓灰质炎病毒衣壳蛋白时，产生>2×10⁶个感染性颗粒/毫升。当以反式提供柯萨奇病毒B3、人鼻病毒14、脑心肌炎病毒或甲型肝炎病毒（HAV）衣壳蛋白时，除HAV外，所有病毒都显示出复制子的一些衣壳化。异源衣壳蛋白对复制子RNA的总体衣壳化效率明显低于使用脊髓灰质炎病毒衣壳时。转衣壳化颗粒可以被针对每种供体病毒衣壳的特异性抗血清完全中和。结果表明衣壳化受特定病毒核酸和蛋白质序列的调控。
