Harger J W, Meskauskas A, Nielsen J, Justice M C, Dinman J D
Department of Molecular Genetics and Microbiology, Graduate Program in Molecular Biosciences at UMDNJ/Rutgers Universities, The Cancer Institute of New Jersey, Piscataway, New Jersey 08854, USA.
Virology. 2001 Jul 20;286(1):216-24. doi: 10.1006/viro.2001.0997.
Programmed ribosomal frameshifting is utilized by a number of RNA viruses to ensure the correct ratio of viral structural to enzymatic proteins for viral particle assembly. Altering frameshifting efficiencies upsets this ratio, inhibiting virus propagation. Two yeast viruses that induce host cell ribosomes to shift translational reading frame were used as tools to explore the interactions between viruses and host cellular protein synthetic machinery. Previous studies showed that the ribosome-inactivating protein pokeweed antiviral protein specifically inhibited propagation of the Ty1 retrotransposable element of yeast as a consequence of inhibition of programmed +1 ribosomal frameshifting. Here, complementary genetic and pharmacological approaches were employed to test whether inhibition of Ty1 retrotransposition is a general feature of alterations in the translocation step of elongation and +1 frameshifting. The results demonstrate that cells harboring a variety of mutant alleles of two host-encoded proteins that are involved in translocation, eukaryotic elongation factor-2 and the ribosome-associated protein RPP0, have Ty1 propagation defects. We also show that sordarin, a fungus-specific inhibitor of eEF-2 function, specifically inhibits programmed +1 ribosomal frameshifting and Ty1 retrotransposition. These findings serve to link inhibition of Ty1 retrotransposition and +1 frameshifting to changes in the translocation step of elongation.
许多RNA病毒利用程序性核糖体移码来确保病毒结构蛋白与酶蛋白的比例正确，以进行病毒粒子组装。改变移码效率会破坏这一比例，从而抑制病毒传播。两种能诱导宿主细胞核糖体改变翻译阅读框的酵母病毒被用作工具，以探索病毒与宿主细胞蛋白质合成机制之间的相互作用。先前的研究表明，核糖体失活蛋白商陆抗病毒蛋白由于抑制了程序性+1核糖体移码，从而特异性地抑制了酵母Ty1逆转座子的传播。在此，我们采用互补的遗传学和药理学方法来测试抑制Ty1逆转座是否是延伸和+1移码转位步骤改变的一个普遍特征。结果表明，携带参与转位的两种宿主编码蛋白（真核延伸因子2和核糖体相关蛋白RPP0）各种突变等位基因的细胞存在Ty1传播缺陷。我们还表明，索德菌素是一种真菌特异性的eEF-2功能抑制剂，它能特异性地抑制程序性+1核糖体移码和Ty1逆转座。这些发现将抑制Ty1逆转座和+1移码与延伸转位步骤的变化联系起来。
