Kondo E, Mammano F, Cohen E A, Göttlinger H G
Division of Human Retrovirology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115, USA.
J Virol. 1995 May;69(5):2759-64. doi: 10.1128/JVI.69.5.2759-2764.1995.
The vpr gene of human immunodeficiency virus type 1 (HIV-1) encodes a virion-associated regulatory protein. Mutagenesis has shown that the virion association of Vpr requires sequences near the C terminus of the HIV-1 Gag polyprotein Pr55gag. To investigate whether Vpr incorporation is mediated by a specific domain of Pr55gag, we examined the ability of chimeric HIV-1/Moloney murine leukemia virus (MLV) Gag polyproteins to direct the incorporation of Vpr. Vpr expressed in trans did not associate with particles formed by the authentic MLV Gag polyprotein or with particles formed by chimeric Gag polyproteins that had the matrix (MA) or capsid (CA) domain of MLV precisely replaced by the corresponding domain of HIV-1HXB2. By contrast, Vpr was efficiently incorporated upon replacement of the C-terminal nucleocapsid (NC) domain of the MLV Gag polyprotein with HIV-1 p15 sequences. Vpr was also efficiently incorporated into particles formed by a MLV Gag polyprotein that had the HIV-1 p6 domain fused to its C terminus. Furthermore, a deletion analysis revealed that a conserved region near the C terminus of the p6 domain is essential for Vpr incorporation, whereas sequences downstream of the conserved region are dispensable. These results show that a virion association motif for Vpr is located within residues 1 to 46 of p6.
人类免疫缺陷病毒1型（HIV-1）的vpr基因编码一种与病毒粒子相关的调节蛋白。诱变研究表明，Vpr与病毒粒子的结合需要HIV-1 Gag多聚蛋白Pr55gag C末端附近的序列。为了研究Vpr的掺入是否由Pr55gag的特定结构域介导，我们检测了嵌合HIV-1/莫洛尼鼠白血病病毒（MLV）Gag多聚蛋白指导Vpr掺入的能力。反式表达的Vpr不与由天然MLV Gag多聚蛋白形成的颗粒结合，也不与由嵌合Gag多聚蛋白形成的颗粒结合，这些嵌合Gag多聚蛋白的基质（MA）或衣壳（CA）结构域被HIV-1 HXB2的相应结构域精确替换。相比之下，当用HIV-1 p15序列替换MLV Gag多聚蛋白的C末端核衣壳（NC）结构域时，Vpr能有效掺入。Vpr也能有效掺入由C末端融合了HIV-1 p6结构域的MLV Gag多聚蛋白形成的颗粒中。此外，缺失分析表明，p6结构域C末端附近的一个保守区域对于Vpr掺入至关重要，而该保守区域下游的序列则是可有可无的。这些结果表明，Vpr的病毒粒子结合基序位于p6的1至46位残基内。
