Effects of palmitoylation of replicase protein nsP1 on alphavirus infection
Effects of palmitoylation of replicase protein nsP1 on alphavirus infection
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DOI：
10.1128/jvi.74.15.6725-6733.2000
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发表时间：
2000-08-01
影响因子：
5.4
通讯作者：
Auvinen, P
中科院分区：
文献类型：
--
作者：
Ahola, T;Kujala, P;Auvinen, P
与膜相关的甲病毒RNA复制复合物包含四个病毒编码的亚基，即非结构蛋白nsP1至nsP4。塞姆利基森林病毒（SFV）的nsP1通过半胱氨酸418至420的棕榈酰化进行疏水修饰。在此我们表明，辛德毕斯病毒的nsP1在相同位点（半胱氨酸420）也被棕榈酰化。当将阻止nsP1棕榈酰化的突变引入这两种甲病毒的基因组时，突变病毒仍然具有活性并能复制到高效价，尽管其生长稍有延迟。在突变体中，棕榈酰化缺陷型nsP1的亚细胞分布发生了改变：它不再定位于丝状伪足延伸部分，并且一部分是可溶的。甲病毒复制位点的超微结构看起来正常，并且其他非结构蛋白在突变体中的定位未改变。在野生型和突变病毒感染的细胞中，SFV的nsP3和nsP4只有用碱性溶液才能从膜上提取出来，而nsP2与膜的结合较松散。因此，甲病毒RNA复制复合物的膜结合特性不是由nsP1的棕榈酰化决定的。nsP1棕榈酰化缺陷型甲病毒在几种细胞类型中产生正常的空斑，但在HeLa细胞中不能形成空斑，尽管它们诱导了这些细胞的正常凋亡。SFV突变体在小鼠中无致病性：它引起血液病毒血症，但在大脑中未检测到传染性病毒。
The membrane-associated alphavirus RNA replication complex contains four virus-encoded subunits, the nonstructural proteins nsP1 to nsP4. Semliki Forest virus (SFV) nsP1 is hydrophobically modified by palmitoylation of cysteines 418 to 420, Here we show that Sindbis virus nsP1 is also palmitoylated on the same site (cysteine 420), When mutations preventing nsP1 palmitoylation were introduced into the genomes of these two alphaviruses, the mutant viruses remained viable and replicated to high titers, although their growth was slightly delayed. The subcellular distribution of palmitoylation-defective nsP1 was altered in the mutant: it no longer localized to filopodial extensions, and a fraction of it was soluble, The ultrastructure of the alphavirus replication sites appeared normal, and the Localization of the other nonstructural proteins was unaltered in the mutants. In both wild-type- and mutant-virus-infected cells, SFV nsP3 and nsP4 could be extracted from membranes only by alkaline solutions whereas the nsP2-membrane association was looser. Thus, the membrane binding properties of the alphavirus RNA replication complex were not determined by the palmitoylation of nsP1, The nsP1 palmitoylation-defective alphaviruses produced normal plaques in several cell types, but failed to give rise to plaques in HeLa cells, although they induced normal apoptosis of these cells. The SFV mutant was apathogenic in mice: it caused blood viremia, but no infectious virus was detected in the brain.