Sindbis virus nonstructural protein nsP2 is cytotoxic and inhibits cellular transcription
Sindbis virus nonstructural protein nsP2 is cytotoxic and inhibits cellular transcription
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DOI：
10.1128/jvi.02739-05
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发表时间：
2006-06-01
影响因子：
5.4
通讯作者：
Frolov, Ilya
中科院分区：
文献类型：
--
作者：
Garmashova, Natalia;Gorchakov, Rodion;Frolov, Ilya
甲病毒在脊椎动物细胞中的复制强烈影响细胞生理学，并最终导致细胞病变效应（CPE）和细胞死亡的发展。辛德毕斯病毒（SIN）复制引起细胞大分子合成的重大变化，其中细胞mRNA和rRNA转录的强烈下调起着关键作用。SIN非结构蛋白nsP 2以前被认为是病毒-宿主细胞相互作用的主要调节因子之一，因为nsP 2羧基端部分的点突变可以使SIN和其他甲病毒和复制子的细胞病变性降低，并且能够在一些脊椎动物细胞系中持续存在。这些突变体不能抑制转录和下调病毒应激诱导的细胞反应。在目前的工作中，我们证明：（i）SIN nsP 2是关键参与CPE的发展，不仅在复制SIN特异性RNA，而且当这种蛋白质单独表达从不同的表达盒;（ii）SIN nsP 2的细胞毒性效应似乎至少部分地由其能力，导致转录关闭;（iii）SIN nsP 2的这些功能由位于其解旋酶和蛋白酶结构域之外的该蛋白的羧基末端肽的完整性决定，而不是由其蛋白酶活性决定;和（iv）SIN nsP 2的细胞毒活性取决于该蛋白以游离形式存在，并且P123加工的改变消除了nsP 2引起CPE的能力。
Replication of alphaviruses in vertebrate cells strongly affects cell physiology and ultimately leads to development of a cytopathic effect (CPE) and cell death. Sindbis virus (SIN) replication causes major changes in cellular macromolecular synthesis, in which the strong downregulation of transcription of cellular mRNAs and rRNAs plays a critical role. SIN nonstructural protein nsP2 was previously proposed as one of the main regulators of virus-host cell interactions, because point mutations in the carboxy-terminal part of nsP2 could make SIN and other alphaviruses and replicons less cytopathic and capable of persisting in some vertebrate cell lines. These mutants were incapable of inhibiting transcription and downregulating a viral stress-induced cell response. In the present work, we demonstrate that (i) SIN nsP2 is critically involved in CPE development, not only during the replication of SIN-specific RNAs, but also when this protein is expressed alone from different expression cassettes; (ii) the cytotoxic effect of SIN nsP2 appears to be at least partially determined by its ability to cause transcriptional shutoff; (iii) these functions of SIN nsP2 are determined by the integrity of the carboxy-terminal peptide of this protein located outside its helicase and protease domains, rather than by its protease activity; and (iv) the cytotoxic activity of SIN nsP2 depends on the presence of this protein in a free form, and alterations in P123 processing abolish the ability of nsP2 to cause CPE.