Characterization of the antiviral activity of BCA2

项目摘要 BCA 2（乳腺癌相关基因2，也称为RNF 115、ZNF 364或Rabring 7）是一种细胞质型乳腺癌相关基因。 环指E3泛素连接酶，在大多数乳腺癌细胞系中响应雌激素而上调。一 最近的研究表明，BCA 2与Tetherin的胞质结构域相互作用，促进内化 和溶酶体降解系留的HIV-1颗粒，并且BCA 2的E3连接酶活性降低， 以增强Tetherin介导的对HIV-1的限制。因此，BCA 2将充当系链蛋白辅因子， 在不表达tetherin的细胞中缺乏抗病毒活性。然而，在这里，我们表明BCA 2抑制病毒， 通过降低HIV-1 Gag的细胞水平，以不依赖于栓系蛋白的方式生产，并且这种活性 需要E3连接酶活性。此外，我们发现BCA 2与Gag发生物理相互作用，并促进其 泛素化，这表明BCA 2可能是一种先天性抗病毒因子，靶向Gag多蛋白， 降解，从而阻碍病毒组装。我们想通过描述 BCA 2（Specific Aim 1）抗病毒活性的分子机制， 以及参与调节BCA 2活性的细胞通路（特异性目的2）。更好的 了解限制病毒产生的先天机制将有助于抗逆转录病毒药物的研制。 抑制病毒在受影响个体中复制的药物。因此，这里概述的目标直接 这与确定抗逆转录病毒治疗的新靶点以控制HIV-1感染有关。

PROJECT SUMMARY BCA2 (Breast Cancer-Associated gene 2, also known as RNF115, ZNF364 or Rabring7) is a cytoplasmic RING-finger E3 ubiquitin ligase that is upregulated in most breast cancer cell lines in response to estrogen. A recent study showed that BCA2 interacts with the cytoplasmic domain of tetherin to promote the internalization and lysosomal degradation of tethered HIV-1 particles, and that the E3 ligase activity of BCA2 is dispensable to enhance the tetherin-mediated restriction of HIV-1. Therefore, BCA2 would act as a tetherin co-factor, lacking antiviral activity in cells that do not express tetherin. However, here we show that BCA2 inhibits virus production in a tetherin-independent manner by reducing the cellular levels of HIV-1 Gag, and that this activity requires the E3 ligase activity. Furthermore, we show that BCA2 physically interacts with Gag and promotes its ubiquitination, suggesting that BCA2 may be an innate antiviral factor that targets the Gag polyprotein for degradation, thereby, impeding virus assembly. We want to formally address this hypothesis by characterizing the molecular mechanisms of the antiviral activity of BCA2 (Specific Aim 1) and by identifying the molecules and cellular pathways that participate in the regulation of BCA2's activity (Specific Aim 2). A better understanding of the innate mechanisms that limit virus production will help in the elaboration of antiretroviral drugs to contain virus replication in affected individuals. Therefore, the objectives outlined here are directly relevant to identifying new targets for antiretroviral therapy to control HIV-1 infection.