HIV-1潜伏是AIDS不能治愈的根本原因，缺乏适合的HIV-1直接感染动物模型限制了对潜伏机制的研究。平顶猴是唯一易感HIV-1的旧大陆猴，我们前期首次阐明了其易感的分子机制，发现HIV-1在北平顶猴体内呈低水平复制和长期潜伏特征，而潜伏可能与HIV-1mRNA剪接受阻有关。HIV-1 Tat是重要的HIV-1mRNA剪接调控蛋白，我们提出Tat在北平顶猴中功能受限从而抑制HIV-1mRNA剪接的假说。本申请拟开展：鉴定北平顶猴中HIV-1mRNA剪接受阻的具体位点。比较分析北平顶猴与人细胞中Tat的序列、修饰、与调节因子作用是否存在差异，从而导致剪接效率不同。通过体外定点突变和体内分离突变株，研究Tat和相关剪接因子变异在剪接受阻中作用及对复制的影响；筛选出毒力增强的突变病毒株体内感染北平顶猴。本研究将为阐明HIV-1复制的精细分子机制，创建合适的HIV-1北平顶猴模型奠定科学依据。

The persistence of HIV latency is a major barrier to curing AIDS and eradicating HIV. The lack of suitable animal models that mimic latent HIV-1 infections has also hindered attempts to develop effective strategies for eradicating infections. Among the old world monkeys, the pig-tailed macaques are the only Old World monkeys known to be susceptible to HIV-1 infection. We have firstly found they lack an HIV-1 restriction factor TRIM5α, which gives a potential molecular mechanism that can explain why the pig-tailed macaque is prone to HIV-1 infection. Northern pig-tailed macaque (Macaca leonina, NPM) is one species of PTMs and lives in southwest China. In our previous study, we have founded NPMs can be infected with HIV-1 in vivo and observed different HIV-1 strains can replicated at a low level and be latent in these macaques. Further researches identified that HIV-1 mRNA splicing was greatly inhibited in viral replication, which may be contributed to HIV-1 latency. The Tat protein of HIV-1 plays an important role in the regulation of viral mRNA splicing. Thus, we put forward a hypothesis that Tat protein lost its function in the regulation of viral mRNA splicing in NPMs, which lead to HIV-1 latency in vivo. To demonstrate it, in this study, the specific location of HIV-1 mRNA splicing inhibition in nucleus will be checked and the characteristics of the blockage of HIV-1mRNA splicing will be determined. To elucidate molecular mechanism of Tat in regulating HIV-1 mRNA splicing in NPMs, the modification of different Tat mutants and their interaction with regulatory proteins and regulatory sequences will be analyzed in NPM and human cells. By site-directed mutation in vitro and isolation of mutants in vivo of NPMs, the variations of Tat and its related splicing regulatory proteins and regulatory sequence will be constructed, and their roles in HIV-1 mRNA splicing and effects on replication will be identified, and on the other hand, the HIV-1 strains with virulent mutants will be selected out. NPMs will be infected with virulent HIV-1 strains with Tat related mutants. This work will contribute to elucidate the complex molecular mechanism of HIV-1 replication, and establish a suitable HIV/AIDS animal model of NPMs that directly infected with HIV-1.