Hunt D M, Mehta R, Hutchinson K L
Department of Microbiology and Immunology, University of South Carolina School of Medicine, Columbia 29208.
J Gen Virol. 1988 Oct;69 ( Pt 10):2555-61. doi: 10.1099/0022-1317-69-10-2555.
TsG16(I) is a temperature-sensitive (ts) mutant of vesicular stomatitis virus, Indiana serotype, which overproduces polyadenylic acid [poly(A)] in an in vitro transcription system due to a mutation in the L protein. Others have reported that L-S-adenosylhomocysteine (S-Ado-Hcy) causes wild-type (wt) virus to overproduce poly(A) in vitro. The possibility that tsG16(I) constitutively expresses a property induced by S-Ado-Hcy in the case of wt virus was found not to be so since polyadenylation by the mutant was still sensitive to S-Ado-Hcy. Indeed, S-Ado-Hcy caused tsG16(I) to overproduce poly(A) in vitro to a greater extent than its parental wt virus. The increase in polyadenylation observed in response to saturating levels of S-Ado-Hcy differed for tsG16(I), for its parental wt virus and for another wt strain. To characterize which viral protein modulated the polyadenylation response to S-Ado-Hcy, purified virions were fractionated and their phenotypes in homologous and heterologous reconstitution assays were examined. The results indicated that the viral L protein modulated the response in all three stocks of virus. These data provide further evidence to suggest that the L protein of vesicular stomatitis virus plays a role in polyadenylation of the viral mRNA.
TsG16(I)是水泡性口炎病毒印第安纳血清型的一种温度敏感（ts）突变体，由于L蛋白发生突变，它在体外转录系统中会过量产生聚腺苷酸[poly(A)]。其他人曾报道，L-S-腺苷同型半胱氨酸（S-Ado-Hcy）会使野生型（wt）病毒在体外过量产生poly(A)。结果发现，tsG16(I)在wt病毒情况下组成性表达由S-Ado-Hcy诱导的特性这种可能性并不成立，因为该突变体的聚腺苷酸化对S-Ado-Hcy仍敏感。实际上，S-Ado-Hcy使tsG16(I)在体外比其亲代wt病毒更大程度地过量产生poly(A)。对于tsG16(I)、其亲代wt病毒和另一个wt毒株，响应饱和水平的S-Ado-Hcy时观察到的聚腺苷酸化增加情况有所不同。为了表征哪种病毒蛋白调节对S-Ado-Hcy的聚腺苷酸化反应，对纯化的病毒粒子进行了分级分离，并检测了它们在同源和异源重组试验中的表型。结果表明，病毒L蛋白调节了所有三株病毒中的反应。这些数据提供了进一步的证据，表明水泡性口炎病毒的L蛋白在病毒mRNA的聚腺苷酸化中起作用。
