Role of TNPO3 in HIV-1 Replication

说明(申请人提供)：TNPO3是HIV-1感染所需的一种细胞核进口受体。TnPO3表达缺失可显著降低HIV-1、HIV-2和SIVmac等灵长类慢病毒的感染。TNPO3对于HIV-1复制的早期步骤至关重要。HIV-1感染中需要TNPO3的病毒决定因素已被基因定位到病毒衣壳上。与这些观察结果一致，我们已经证明了TNPO3特异性地结合了由衣壳组成的HIV-1核心。这些结果表明，TNPO3可能在感染早期就与传入的HIV-1核心相互作用。TNPO3的耗尽适度但持续地影响HIV-1的脱壳过程。人们认为TNPO3参与了HIV-1前整合复合体(PIC)的核进口；然而，这种解释值得商榷，因为最近的证据表明，TNPO3在核进口后有助于HIV-1的复制。考虑到以下证据：1)耗尽 TNPO3的表达影响HIV-1的复制，2)需要TNPO3的病毒决定因素映射到衣壳，3)TNPO3与HIV-1衣壳结合，4)TNPO3表达的缺失适度但持续地影响去涂层，以及5)我们最近的观察到，TNPO3在核输入之后但整合之前的一步中辅助HIV-1的复制。我们将测试这一假设，即当前整合复合体到达细胞核时，TNPO3与细胞质中HIV-1核心的结合允许发生生产性感染所需的过程。这项建议将通过监测在没有TNPO3的情况下HIV-1整合酶介导的两个关键过程，即3‘-启动子加工和DNA链转移，来探讨TNPO3对HIV-1整合到基因组中的贡献。其次，我们将研究TNPO3核进口在HIV-1感染中的作用。这些研究的目的是了解TNPO3用来帮助HIV-1复制的机制，未来的目标是将TNPO3用作阻断HIV-1复制的治疗靶点。好了！

DESCRIPTION (provided by applicant): TNPO3 is a cellular nuclear import receptor required for HIV-1 infection. Depletion of TNPO3 expression dramatically decreases the infection of primate lentiviruses such as HIV-1, HIV-2 and SIVmac. TNPO3 is essential for early steps on HIV-1 replication. The viral determinant for the requirement of TNPO3 in HIV-1 infection has been genetically mapped to the viral capsid. In agreement with these observations, we have demonstrated that TNPO3 specifically binds the HIV-1 core that is composed of capsid. These results imply that TNPO3 might be interacting with the incoming HIV-1 core early on infection. Depletion of TNPO3 moderately but consistently affects the uncoating process of HIV-1. It is believed that TNPO3 is involved in the nuclear import of the HIV-1 pre-integration complex (PIC); however, this interpretation is in question, as more recent evidence implies that TNPO3 assists HIV-1 replication after nuclear import. Considering the following evidence: 1) depletion of TNPO3 expression affects HIV-1 replication, 2) the viral determinant for the requirement of TNPO3 maps to capsid, 3) TNPO3 binds the HIV-1 capsid, 4) depletion of TNPO3 expression moderately but consistently affects uncoating, and 5) our recent observation that TNPO3 assists HIV-1 replication in an step after nuclear import but before integration. We will test the hypothesis that the binding of TNPO3 to the HIV-1 core in the cytoplasm allows the occurrence of a process that is required for productive infection when the pre-integration complex reaches the nucleus. This proposal will explore the contribution of TNPO3 to HIV-1 integration into the genome by monitoring the two pivotal processes mediated by HIV-1 integrase in the absence of TNPO3, namely 3'-prime processing and DNA strand transfer. Secondly, we will study the role of TNPO3 nuclear-import in HIV-1 infection. The goal of these studies are to understand the mechanism used by TNPO3 to assist HIV-1 replication with the future objective of using TNPO3 as a therapeutic target to block HIV-1 replication. !