Role of cellular Helicases and Nucleases in HIV-1 infection and lentiviral transduction.

HIV-1需要通过逆转录（RT）将其单链RNA基因组转化为线性双链DNA，然后才能整合到宿主细胞基因组中。最近的研究表明，HIV-1衣壳在到达或通过核孔之前可能保持完整，从而保护RT中间体免受降解和先天免疫感知。然而，在整合之前，病毒的双链dna必须离开它的保护壳。我们的研究结果表明，这为细胞解旋酶和核酸酶降解最终的RT产物提供了一个机会窗口，并在HIV-1成为不可逆地整合到细胞基因组之前阻止它。因此，限制前病毒整合可能直接限制潜伏HIV-1储存库的大小以及慢病毒基因传递的效率。在拟建的项目中，我们将确定BLM、EXO1、DNA2以及其他细胞解旋酶和核酸酶对原代CD4+ T细胞和巨噬细胞HIV-1感染和先天免疫激活的影响。此外，还将研究解旋酶/核酸酶逃避或对抗的病毒机制。最后，我们将确定DNA修复因子是否影响慢病毒基因传递的效率以及由此产生的不希望的先天免疫激活水平。我们的发现将为减少hiv -1感染者有害的慢性免疫激活和潜伏病毒库的大小提供新的机会，并可能有助于提高慢病毒基因转移的效率和安全性。

HIV-1 needs to perform reverse transcription (RT) to convert its single-stranded (ss) RNA genome into linear double-stranded (ds) DNA prior to integration into the host cell genome. Recent studies have shown that HIV-1 capsids may remain intact until they reach or pass the nuclear pores thereby shielding RT intermediates from degradation and innate immune sensing. Prior to integration, however, the viral dsDNA must leave its protective shell. Our results suggest that this provides a window of opportunity for cellular helicase and nucleases to degrade the final RT product and to block HIV-1 just before it becomes irreversibly integrated into the cellular genome. Thus, restriction of proviral integration may directly limit the size of the latent HIV-1 reservoirs as well as the efficiency of lentiviral gene delivery. In the proposed project, we will determine the impact of BLM, EXO1, DNA2 as well as other cellular helicases and nuclease on HIV-1 infection and innate immune activation in primary CD4+ T cells and macrophages. In addition, viral mechanisms of helicase/nuclease evasion or counteraction will be investigated. Finally, we will determine whether DNA repair factors affect the efficiency of lentiviral gene delivery and the resulting levels of undesired innate immune activation. Our findings will provide new opportunities to reduce harmful chronic immune activation and the size of latent viral reservoirs in HIV-1-infected individuals, and may help to improve the efficiency and safety of lentiviral gene transfer.