Popova Elena, Popov Sergei, Göttlinger Heinrich G
Program in Gene Function and Expression, Program in Molecular Medicine, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605, USA.
J Virol. 2010 Jul;84(13):6590-7. doi: 10.1128/JVI.00035-10. Epub 2010 Apr 28.
To facilitate the release of infectious progeny virions, human immunodeficiency virus type 1 (HIV-1) exploits the Endosomal Sorting Complex Required for Transport (ESCRT) pathway by engaging Tsg101 and ALIX through late assembly (L) domains in the C-terminal p6 domain of Gag. However, the L domains in p6 are known to be dispensable for efficient particle production by certain HIV-1 Gag constructs that have the nucleocapsid (NC) domain replaced by a foreign dimerization domain to substitute for the assembly function of NC. We now show that one such L domain-independent HIV-1 Gag construct (termed Z(WT)) that has NC-p1-p6 replaced by a leucine zipper domain is resistant to dominant-negative inhibitors of the ESCRT pathway that block HIV-1 particle production. However, Z(WT) became dependent on the presence of an L domain when NC-p1-p6 was restored to its C terminus. Furthermore, when the NC domain was replaced by a leucine zipper, the p1-p6 region, but not p6 alone, conferred sensitivity to inhibition of the ESCRT pathway. In an authentic HIV-1 Gag context, the effect of an inhibitor of the ESCRT pathway on particle production could be alleviated by deleting a portion of the NC domain together with p1. Together, these results indicate that the ESCRT pathway dependence of HIV-1 budding is determined, at least in part, by the NC-p1 region of Gag.
为促进感染性子代病毒粒子的释放，1型人类免疫缺陷病毒（HIV-1）通过其Gag蛋白C端p6结构域中的晚期组装（L）结构域与Tsg101和ALIX结合，利用运输所需的内体分选复合体（ESCRT）途径。然而，已知对于某些HIV-1 Gag构建体而言，p6中的L结构域对于高效产生病毒粒子并非必需，这些构建体的核衣壳（NC）结构域被一个外源二聚化结构域取代，以替代NC的组装功能。我们现在表明，一种这样的不依赖L结构域的HIV-1 Gag构建体（称为Z(WT)），其NC-p1-p6被一个亮氨酸拉链结构域取代，对阻断HIV-1病毒粒子产生的ESCRT途径的显性负性抑制剂具有抗性。然而，当NC-p1-p6恢复到其C端时，Z(WT)变得依赖于L结构域的存在。此外，当NC结构域被亮氨酸拉链取代时，p1-p6区域（而非单独的p6）赋予了对ESCRT途径抑制的敏感性。在真实的HIV-1 Gag背景下，通过删除一部分NC结构域和p1，可以减轻ESCRT途径抑制剂对病毒粒子产生的影响。这些结果共同表明，HIV-1出芽对ESCRT途径的依赖性至少部分由Gag的NC-p1区域决定。
