HIV-1 capsid assembly intermediates: cellular factors and links to pathogenesis

在这个抗逆转录病毒药物被用于治疗和预防艾滋病的时代，迫切需要发现新的药物靶点和新的抗逆转录病毒药物。病毒组装是HIV-1生命周期的一个复杂阶段，其中包含鲜为人知的药物靶点。这些靶点尚未得到充分研究，部分原因是HIV-1组装领域尚未解决的争议。该领域一直被自组装模型所主导，该模型是基于HIV-1 Gag在一个理想化的体外系统中自发组装的发现，该系统不概括细胞内环境。相反，这个应用是基于一个模型，提出细胞内环境存在组装障碍，病毒利用细胞酶克服这些障碍。研究表明，在未成熟的衣壳组装过程中，HIV-1 Gag通过由细胞蛋白组成的组装中间体的逐步能量依赖途径进行，包括两种促进组装的细胞酶，atp酶ABCE1和RNA解旋酶DDX6。因此，虽然HIV-1可以在理想的体外系统中自发组装，但细胞研究表明，HIV-1衣壳的组装至少需要两种宿主酶的促进。支持宿主催化ABCE1组装途径的进一步证据来自Prosetta抗病毒公司发现的靶向该途径的新型抗逆转录病毒化合物。今年夏天，百时美施贵宝宣布与Prosetta抗病毒药物公司合作开发这些新型抗逆转录病毒化合物。尽管在药物开发领域取得了这一突破，但对ABCE1途径的了解仍然很少。Aim 1的研究将测试ABCE1是否作为募集细胞机制的接头，并将确定Gag-ABCE1的结合位点，这似乎涉及Gag高度保守的主要同源区域。Aim 2将通过确定Paul Bieniasz实验室发现的首先与HIV-1基因组RNA相关联的含有gag的复合物是否与含有ABCE1的组装中间体相对应，从而帮助建立一个统一的组装模型。Aim 3将使用Eric Hunter小组产生的病毒来检查体内出现的Gag多态性是否可以改变病毒与宿主的相互作用，从而导致病毒组装动力学增加，病毒产量增加，感染个体的病毒载量增加。确定影响病毒产生的病毒-宿主相互作用可能会导致未来针对此类相互作用的策略。总之，这种“从实验室到病床”的应用将促进我们对结合Gag的细胞组装促进剂的理解，

DESCRIPTION: In this era in which antiretroviral drugs are being used for both treatment and prevention of AIDS, there is an urgent need for discovery of new drug targets and novel antiretroviral agents. Virus assembly is a complex stage of the HIV-1 life cycle that contains poorly understood drug targets. These targets are understudied, in part because of unresolved controversies in the HIV-1 assembly field. The field has been dominated by the self-assembly model, which is based on the finding that HIV-1 Gag assembles spontaneously in an idealized in vitro system that does not recapitulate the intracellular environment. In contrast, this application is based on a model proposing that the intracellular environment presents barriers to assembly, which the virus overcomes using cellular enzymes. This model is supported by studies demonstrating that during immature capsid assembly, HIV-1 Gag progresses through a stepwise, energy-dependent pathway of assembly intermediates composed of cellular proteins, including two cellular enzymes that facilitate assembly, the ATPase ABCE1 and the RNA helicase DDX6. Thus, while HIV-1 can assemble spontaneously in an idealized in vitro system, studies in cells indicate that HIV-1 capsid assembly is facilitated by at least two host enzymes. Further evidence in favor of the host-catalyzed ABCE1 assembly pathway comes from the discovery by Prosetta Antiviral of novel antiretroviral compounds that target this pathway. This summer Bristol Myers Squibb announced a partnership with Prosetta Antiviral to develop these novel antiretroviral compounds. Despite this breakthrough in the area of drug development, the ABCE1 pathway remains poorly understood. Studies in Aim 1 will test whether ABCE1 acts as an adaptor for recruiting cellular machinery and will also define the Gag-ABCE1 binding site, which appears to involve the highly conserved major homology region of Gag. Aim 2 will help establish a unified model of assembly by determining whether the Gag-containing complex that first associates with HIV-1 genomic RNA, identified by Paul Bieniasz's lab, corresponds to an ABCE1- containing assembly intermediate. Aim 3 will uses viruses generated by Eric Hunter's group to examine whether Gag polymorphisms that arise in vivo can alter viral host interactions, leading to increased virus assembly kinetics, greater virus production, and higher viral loads in infected individuals. Identifying viral-host interactions that impact virus production could lead t strategies for targeting such interactions in the future. In sum, this "bench to bedside" application will advance our understanding of a cellular facilitator of assembly that binds to Gag, help reach a consensus model of HIV-1 capsid packaging, and provide insights into how viral-host interactions in assembly affect pathogenesis.