APOBEC3G/CEM15 Inhibition of Lentivirus Replication

人类基因组中的7个APOBEC3基因（APOBEC3A、B、C、DE、F、G和H）编码抗病毒胞苷脱氨酶。脱氨酶被专门包装到病毒粒子中，在病毒逆转录物的负链中脱氨胞嘧啶核苷酸。Vif辅助蛋白通过结合和诱导其降解来抵消APOBEC3F和G。该项目将研究APOBEC3生物学的几个特征。特异性目标1将产生一组针对家族成员的单克隆抗体，并使用这些抗体来表征单个家族成员的组织和细胞型表达。每个家族成员将在稳定的细胞系中进行测试，以评估其对HIV-1和SIV的抗病毒活性。具体目的2将研究APOBEC3基因的转录调控。微阵列表达谱分析将用于通过发现密切匹配的非允许细胞和允许细胞之间的表达差异来识别调节APOBEC3基因转录的转录因子。将鉴定出与APOBEC3G共调控的细胞基因。APOBEC3G启动子中的转录因子结合位点将被确定，以确定该基因是如何被调节的，并提供影响启动子活性的方法，从而增加细胞内保护性APOBEC3蛋白的水平。特异性目的3将研究APOBEC3蛋白被包装成病毒粒子的机制，并研究APOBEC3在只有一个APOBEC3基因的小鼠中的作用。Specific aim 4将利用小鼠模型研究APOBEC3在免疫应答中的作用。这些研究将利用APOBEC3敲除小鼠来研究APOBEC3在体内抑制逆转录病毒复制的机制，以及该蛋白是否在抑制逆转录转座子中发挥作用，还是在免疫系统中发挥尚未确定的作用。

The 7 APOBEC3 genes (APOBEC3A, B, C, DE, F, G and H) in the human genome encode antiviral cytidine deaminases. The deaminases are specifically packaged into virions where they deaminate cytosine nucleotides in the minus-strand of the viral reverse transcripts. The Vif accessory protein counteracts APOBEC3F and G by binding and inducing their degradation. The project will investigate several features APOBEC3 biology. Specific aim 1 will generate a panel of monoclonal antibodies against the family members and use these to characterize the tissue and cell-type expression of the individual family members. Each family member will be tested in stable cell lines to evaluate their antiviral activity against HIV-1 and SIV. Specific aim 2 will investigate the transcriptional regulation of the APOBEC3 genes. Microarray expression profiling will be used to identify the transcription factors that regulate transcription of the APOBEC3 genes by finding expression differences between closely matched nonpermissive and permissive cells. Cellular genes will be identified that are co-regulated with APOBEC3G. Transcription factor binding sites in the APOBEC3G promoter will be identified to define how the gene is regulated and to provide insight into ways to influence promoter activity that would increase the intracellular levels of protective APOBEC3 proteins. Specific aim 3 will investigate the mechanisms by which APOBEC3 proteins are packaged into virions will study the role of APOBEC3 in the mouse which has only a single APOBEC3 gene. Specific aim 4 will use the mouse model to study the role of APOBEC3 in the immune response. The studies will make use of an APOBEC3 knock-out mouse to investigate the mechanism by which APOBEC3 suppresses retrovirus replication in vivo and whether the protein plays a role in the suppression of retrotransposons or a yet unidentified role in the immune system.