TRANSLATIONAL CONTROL OF PROTEIN-SYNTHESIS AFTER INFECTION BY VESICULAR STOMATITIS-VIRUS
TRANSLATIONAL CONTROL OF PROTEIN-SYNTHESIS AFTER INFECTION BY VESICULAR STOMATITIS-VIRUS
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DOI：
10.1128/jvi.36.3.719-733.1980
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发表时间：
1980-01-01
影响因子：
5.4
通讯作者：
PORTER, M
中科院分区：
文献类型：
--
作者：
LODISH, HF;PORTER, M
水泡性口炎病毒(VSV)感染BHK[仓鼠肾]细胞4h后，细胞总蛋白合成速率约为未感染细胞的65%，12-15种主要细胞多肽的合成水平约为对照细胞的25%。通过对分离的RNA进行体外翻译以及产物的一维和二维凝胶分析，所有主要的细胞mRNA在感染后都保持完整和可翻译。感染后，每细胞可翻译的信使核糖核酸总量增加了约3倍；这一额外的信使核糖核酸直接合成了5个VSV结构蛋白。为了确定感染前后细胞和病毒mRNA的亚细胞定位，从感染和未感染的细胞中提取不同大小的多聚体和非多聚体核糖核蛋白(RNP)的RNA并进行体外翻译。在对照细胞中，80%以上的优势种细胞内的信使核糖核酸与多聚体结合，而在感染细胞中，60%以上与多聚体结合。在感染和未感染的细胞中，12种主要的可翻译细胞mRNA中只有2种定位于RNP组分。感染后，翻译单个细胞mRNA的多聚体的平均大小减少了约2-3倍。在未感染的细胞中，肌动蛋白主要存在于具有12个核糖体的多聚体上，例如(Mw 42,000)mRNA；感染后，在具有5个核糖体的多聚体上发现，与翻译VSV N(Mw 52,000)和M(Mw 35,000)m RNA的多聚体大小相同。因此，VSV感染后细胞蛋白质合成的抑制在很大程度上是由于大量过剩的病毒mRNA竞争核糖体。在被感染的细胞中，启动细胞和病毒mRNA翻译的效率大致相同；细胞核糖体只是分布在比生长中的细胞中更多的mRNA中。约20-30%的优势细胞和病毒的mRNA存在于感染细胞中的RNP颗粒中，推测它们在蛋白质合成中不活跃。RNP感染后不存在细胞或病毒mRNA的优先滞留。
At 4 h after infection of BHK [hamster kidney] cells by vesicular stomatitis virus (VSV), the rate of total protein synthesis was about 65% that of uninfected cells and synthesis of the 12-15 predominant cellular polypeptides was reduced to a level of about 25% that of control cells. As determined by in vitro translation of isolated RNA and 1- and 2-dimensional gel analyses of the products, all predominant cellular mRNA remained intact and translatable after infection. The total amount of translatable mRNA per cell increased about 3-fold after infection; this additional mRNA directed synthesis of the 5 VSV structural proteins. To determine the subcellular localization of cellular and viral mRNA before and after infection, RNA from various sizes of polysomes and nonpolysomal ribonucleoproteins (RNP) was isolated from infected and noninfected cells and translated in vitro. Over 80% of most predominant species of cellular mRNA was bound to polysomes in control cells and over 60% was bound in infected cells. Only 2 of the 12 predominant species of translatable cellular mRNA were localized to the RNP fraction, both in infected and in uninfected cells. The average size of polysomes translating individual cellular mRNA was reduced about 2- to 3-fold after infection. In uninfected cells, actin, e.g., (MW 42,000) mRNA was found predominantly on polysomes with 12 ribosomes; after infection, it was found on polysomes with 5 ribosomes, the same size of polysomes that were translating VSV N (MW 52,000) and M (MW 35,000) mRNA. Thus, the inhibition of cellular protein synthesis after VSV infection is due, in large measure, to competition for ribosomes by a large excess of viral mRNA. The efficiency of initiation of translation on cellular and viral mRNA is about the same in infected cells; cellular ribosomes are simply distributed among more mRNA than are present in growing cells. About 20-30% of each of the predominant cellular and viral mRNA were present in RNP particles in infected cells and were presumably inactive in protein synthesis. There was no preferential sequestration of cellular or viral mRNA in RNP after infection.