Michienzi Alessandro, Li Shirley, Zaia John A, Rossi John J
Divisions of Molecular Biology and Virology, Beckman Research Institute of the City of Hope, 1450 East Duarte Road, Duarte, CA 91010-3011, USA.
Proc Natl Acad Sci U S A. 2002 Oct 29;99(22):14047-52. doi: 10.1073/pnas.212229599. Epub 2002 Oct 10.
Tat is a critical regulatory factor in HIV-1 gene expression. It mediates the transactivation of transcription from the HIV-1 LTR by binding to the transactivation response (TAR) element in a complex with cyclin T1. Because of its critical and early role in HIV gene expression, Tat and its interaction with the TAR element constitute important therapeutic targets for the treatment of HIV-1 infection. Based on the known nucleolar localization properties of Tat, we constructed a chimeric small nucleolar RNA-TAR decoy that localizes to the nucleoli of human cells and colocalizes in the nucleolus with a Tat-enhanced GFP fusion protein. When the chimeric RNA was stably expressed in human T lymphoblastoid CEM cells it potently inhibited HIV-1 replication. These results demonstrate that the nucleolar trafficking of Tat is critical for HIV-1 replication and suggests a role for the nucleolus in HIV-1 viral replication.
Tat是HIV-1基因表达中的关键调节因子。它通过与细胞周期蛋白T1形成复合物，结合反式激活应答（TAR）元件，介导HIV-1长末端重复序列（LTR）转录的反式激活。由于Tat在HIV基因表达中起着关键的早期作用，Tat及其与TAR元件的相互作用构成了治疗HIV-1感染的重要治疗靶点。基于已知的Tat核仁定位特性，我们构建了一种嵌合小核仁RNA-TAR诱饵，其定位于人类细胞的核仁，并与Tat增强的绿色荧光蛋白融合蛋白在核仁中共定位。当嵌合RNA在人T淋巴母细胞样CEM细胞中稳定表达时，它能有效抑制HIV-1复制。这些结果表明，Tat的核仁运输对HIV-1复制至关重要，并提示核仁在HIV-1病毒复制中发挥作用。
