病毒潜伏库的存在是全面清除HIV-1感染的主要障碍，而HIV-1 5' LTR的CpG甲基化是病毒潜伏库维持的重要因素。如何有效的激活潜伏病毒，已成为目前清除潜伏库、治愈艾滋病的关键。我们前期研究发现：APOBEC3(A3)家族成员A3A可激活潜伏病毒，并推测这与A3A利用其甲基化胞嘧啶脱氨酶活性，催化5' LTR甲基化CpG去甲基化有关。本项目在此基础上，首先利用体外实验，筛选出A3家族中具有甲基化胞嘧啶脱氨酶活性的分子；然后在5'LTR高度甲基化的J-Lat潜伏细胞中，利用重亚硫酸盐测序、qRT-PCR，探讨这些分子对5' LTR CpG甲基化程度、病毒活化的调节作用；并通过RNA干扰、Co-IP和ChIP，对其催化5' LTR DNA去甲基化的分子机制进行研究。以期揭示A3在激活HIV-1中的作用及其表观遗传学机制，为新型病毒激活剂的研发奠定基础。

HIV latent reservoir is the major barrier to the eradication of HIV-1 infection. Methylation of HIV-1 5' LTR CpG contributes to the maintenance of HIV-1 latency. Currently, the key of reservoir elimination and HIV eradication is how to efficiently reactivate latent virus. Our primary data indicated that A3A from APOBEC3(A3) family was able to reactive the latent HIV-1. And the data also suggests that A3A induced viral reactivation was associated with its 5-methyl cytosine (5mC) deaminase activity via promoting 5' LTR 5mCpG demethylation. Therefore, in this study, the A3 family proteins will be screened to identify the ones with 5-methyl cytosine deaminase activity. Then their functions in promoting 5' LTR CpG demethylation and latency reactivation will be evaluated in highly methylated J-Lat cells, by bisulfite sequencing and qRT-PCR. The mechanisms of promoting 5' LTR demethylation will be studied by RNA interference, Co-IP and ChIP. Overall, our finding will uncover the action of A3 in reactivation of HIV latency and in epigenetic modification; it will also provide valuable information in designing novel latency-reversing agents.