Translation elongation factor 1-alpha interacts specifically with the human immunodeficiency virus type 1 Gag polyprotein
Translation elongation factor 1-alpha interacts specifically with the human immunodeficiency virus type 1 Gag polyprotein
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DOI：
10.1128/jvi.73.7.5388-5401.1999
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发表时间：
1999-07-01
影响因子：
5.4
通讯作者：
Luban, J
中科院分区：
文献类型：
--
作者：
Cimarelli, A;Luban, J
人类免疫缺陷病毒1型（HIV-1）gag编码的蛋白质在病毒生命周期的几乎所有阶段发挥关键作用。由于这些功能可能需要与细胞因子的关联，HIV-1基质蛋白（MA）被用作酵母双杂交筛选的诱饵，以确定MA相互作用的蛋白质。研究发现MA与延伸因子1-α（EF 1 α）相互作用，后者是将氨酰-tRNA传递到核糖体的翻译机制的重要组成部分。EF 1 α随后显示结合整个HIV-1 Gag多蛋白。这种相互作用不仅由Mk介导，而且由核衣壳结构域介导，核衣壳结构域在Gag多蛋白上提供第二个独立的EF 1 α结合位点。EF 1 α被整合到HIV-1病毒体膜内，在那里它被病毒蛋白酶切割，并被外源添加的枯草杆菌蛋白酶保护而不被消化。EF 1 α不与非慢病毒MA结合，也不与莫洛尼鼠白血病病毒粒子结合，这一事实证明了相互作用的特异性。Gag-EF 1 α相互作用似乎是由RNA介导的，因为MA和NC中的碱性残基是结合EF 1 α所必需的，RNA酶破坏了相互作用，并且具有不可检测的EF 1 α结合活性的Gag突变体在其与细胞中tRNA结合的能力方面受损。最后，MA和EF 1 α之间的相互作用损害了体外翻译，这一结果与先前提出的模型一致，在该模型中，通过Gag的积累抑制翻译，从而从多核糖体释放病毒RNA，使RNA被包装成新生病毒粒子。
Human immunodeficiency virus type 1 (HIV-1) gag-encoded proteins play key functions at almost all stages of the viral life cycle. Since these functions may require association with cellular factors, the HIV-1 matrix protein (MA) was used as bait in a yeast two-hybrid screen to identify MA-interacting proteins. MA was found to interact with elongation factor 1-alpha (EF1 alpha), an essential component of the translation machinery that delivers aminoacyl-tRNA to ribosomes. EF1 alpha was then shown to bind the entire HIV-1 Gag polyprotein. This interaction is mediated not only by Mk, but also by the nucleocapsid domain, which provides a second, independent EF1 alpha-binding site on the Gag polyprotein. EF1 alpha is incorporated within HIV-1 virion membranes, where it is cleaved by the viral protease and protected from digestion by exogenously added subtilisin. The specificity of the interaction is demonstrated by the fact that EF1 alpha does not bind to nonlentiviral MAs and does not associate with Moloney murine leukemia virus virions. The Gag-EF1 alpha interaction appears to be mediated by RNA, in that basic residues in MA and NC are required for binding to EF1 alpha, RNase disrupts the interaction, and a Gag mutant with undetectable EF1 alpha-binding activity is impaired in its ability to associate with tRNA in cells. Finally, the interaction between MA and EF1 alpha impairs translation in vitro, a result consistent with a previously proposed model in which inhibition of translation by the accumulation of Gag serves to release viral RNA from polysomes, permitting the RNA to be packaged into nascent virions.