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。脱氨酶被专门包装成病毒粒子，在那里它们使病毒反转录的负链中的胞嘧啶核苷酸脱氨。Vif辅助蛋白通过结合和诱导APOBEC3F和G的降解来中和它们。该项目将研究APOBEC3生物学的几个特征。特殊目的1将产生一组针对家庭成员的单抗，并使用这些抗体来表征单个家庭成员的组织和细胞类型的表达。每个家庭成员都将在稳定的细胞系中接受测试，以评估他们对HIV-1和SIV的抗病毒活性。特异性目标2将研究APOBEC3基因的转录调控。微阵列表达谱将用于通过发现紧密匹配的不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。将确定与APOBEC3G共同调控的细胞基因。将确定APOBEC3G启动子中的转录因子结合部位，以确定基因是如何调控的，并提供对影响启动子活性的方法的洞察，从而增加细胞内保护性APOBEC3蛋白的水平。具体目的3将研究APOBEC3蛋白被包装成病毒粒子的机制将研究APOBEC3在只有一个APOBEC3基因的小鼠中的作用。特异性目标4将使用小鼠模型来研究APOBEC3在免疫反应中的作用。这项研究将利用APOBEC3基因敲除小鼠来研究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反转录转座子方面发挥作用，或者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.