Lloyd R E, Etchison D, Ehrenfeld E
Proc Natl Acad Sci U S A. 1985 May;82(9):2723-7. doi: 10.1073/pnas.82.9.2723.
Poliovirus infection of HeLa cells results in a rapid shutoff of host protein synthesis but does not inhibit the translation of poliovirus mRNA. It has been suggested that this virus-induced translational control is mediated by the inactivation of a cap binding protein (CBP) complex, and it has been shown that the 220,000-Da component(s) (p220) of the CBP complex is cleaved in infected HeLa cells to form antigenically related peptides of 100,000-130,000 Da. To determine whether the known viral protease (peptide 3C) was the mediator of the cleavage of p220, we used immunoblot techniques to analyze partially purified infected HeLa cell extracts for cleavage activity. We report here that p220 cleavage activity does not copurify with viral peptide 3C or with any precursors containing 3C sequences. We also show that cleavage of p220 can be demonstrated in vitro in HeLa cell extracts under conditions where the functional activity of the poliovirus protease is inhibited by specific antibody.
脊髓灰质炎病毒感染HeLa细胞会导致宿主蛋白质合成迅速停止，但不会抑制脊髓灰质炎病毒mRNA的翻译。有人提出，这种病毒诱导的翻译控制是由帽结合蛋白（CBP）复合物的失活介导的，并且已经表明，CBP复合物的220,000道尔顿成分（p220）在受感染的HeLa细胞中被切割，形成100,000 - 130,000道尔顿的抗原相关肽。为了确定已知的病毒蛋白酶（肽3C）是否是p220切割的介质，我们使用免疫印迹技术分析部分纯化的受感染HeLa细胞提取物的切割活性。我们在此报告，p220切割活性不会与病毒肽3C或任何含有3C序列的前体共纯化。我们还表明，在脊髓灰质炎病毒蛋白酶的功能活性被特异性抗体抑制的条件下，p220的切割可以在HeLa细胞提取物中体外证明。
