Identification of a consensus mutation in M protein of vesicular stomatitis virus from persistently infected cells that affects inhibition of host-directed gene expression
Identification of a consensus mutation in M protein of vesicular stomatitis virus from persistently infected cells that affects inhibition of host-directed gene expression
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DOI：
10.1006/viro.1997.8808
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发表时间：
1997-10-27
期刊：
影响因子：
3.7
通讯作者：
Lyles, DS
中科院分区：
文献类型：
--
作者：
Ahmed, M;Lyles, DS
水疱性口炎病毒(VSV)的病毒基质(M)蛋白除了在病毒组装中发挥作用外，还能抑制宿主导向的基因表达。这项研究的目的是确定M蛋白的序列变化是否有助于减少持续感染VSV的细胞中宿主基因表达的关闭。从持续感染VSV的L细胞中分离到的病毒抑制宿主RNA合成的速度比野生型VSV慢。对该病毒持续种群的M基因进行了克隆和测序。一个突变，即蛋白质序列(N163D)第163位的N到D改变，在所有分子克隆中都是共同的。N163D-M蛋白的合成速度为wt-M蛋白的30%，但其翻转速度与wt-M蛋白相似。表达N163D-M蛋白的mR-NA可抑制氯霉素乙酰转移酶(CAT)基因的表达，但其抑制作用比等量wt-M-mR-NA低6~10倍。这种差异不能用CAT mRNA的翻译差异来解释。因此，当考虑到M蛋白表达的差异时，N163D M蛋白在抑制宿主定向基因表达方面的效果比wt M蛋白低2-3倍，类似于在病毒感染细胞中观察到的宿主转录差异。在大约一半的M基因分子克隆中，除了N163D突变外，还发现了点突变。一个独立分离的分子克隆N163D.2的M基因在其羧基末端区域包含两个额外的点突变。N163D.2 M蛋白在抑制宿主基因表达方面存在严重缺陷，其翻转速度比wt M蛋白快。这些结果是晚餐吗？认为M基因突变有助于减少持续感染VSV的细胞的细胞病变效应的想法。(C)1997年学术出版社。
In addition to its function in virus assembly, the viral matrix (M) protein of vesicular stomatitis virus (VSV) inhibits host-directed gene expression. The goal of this study was to determine whether sequence changes in M protein contribute to a reduced shut off of host gene expression in cells persistently infected with VSV. Viruses isolated from L cells persistently infected with VSV inhibited host RNA synthesis more slowly than wild-type (wt) VSV. M genes of the persistent viral population were cloned and sequenced. One mutation, an N to D change at position 163 of the protein sequence (N163D), was common to all the molecular clones. The N163D M protein was synthesized from transfected mRNA at a rate that was 30% of that of wt M protein, but: was turned over al a rate that was similar to that of wt M protein. Transfection of mRNA encoding N163D M protein inhibited expression of a cotransfected target gene encoding chloramphenicol acetyl transferase (CAT), but the inhibition was 6 to 10 times less effective than transfection of equivalent amounts of wt M mRNA. This difference could not be accounted for by differences in translation of CAT mRNA. Thus, when the differences in M protein expression were taken into account, N163D M protein was 2 to 3 times less effective than wt M protein in the inhibition of host-directed gene expression, similar to the differences in host transcription observed in virus-infected cells. Point mutations in addition to the N163D mutation were found in about half of the M gene molecular clones. The M gene of an independently isolated molecular clone, N163D.2, contained two additional point mutations in its carboxy terminal region. N163D.2 M protein was highly defective in inhibition of host gene expression and was turned over more rapidly than wt M protein. These results supper? the idea that M gene mutations contribute to a reduced cytopathic effect in cells persistently infected with VSV. (C) 1997 Academic Press.