Jin Qingwen, Agrawal Lokesh, Meyer L, Tubiana R, Theodorou Ioannis, Alkhatib Ghalib
Department of Microbiology and Immunology, Indiana University School of Medicine, 635 Barnhill Drive, Rm. 420, Indianapolis, IN 46202, USA.
J Virol. 2008 Mar;82(5):2418-26. doi: 10.1128/JVI.01596-07. Epub 2007 Dec 19.
We have recently demonstrated that the CCR5Delta32 protein interacts with CCR5 and CXCR4 and down-modulates their cell surface expression. We have also reported the absence of detectable expression of the truncated CCR5Delta32 protein in four out of six human immunodeficiency virus-infected (HIV(+)) CCR5(-/-) individuals. To explain the defect in protein expression in these samples, we cloned and sequenced the promoter regions of the six HIV(+) individuals. We have identified several polymorphisms in the CCR5Delta32 promoter region, but these polymorphisms were not associated with significant differences in mRNA levels. Coupled in vitro transcription/translation and polyribosome analysis demonstrated a strong association between a variant genotype designated CCR5Delta32 59537-A/A and a low translation efficiency. Protein analysis indicated that the peripheral blood mononuclear cells from two of the HIV(+) CCR5(-/-) individuals carrying the CCR5Delta32 59537-A/A variant expressed trace amounts of CCR5Delta32 protein compared to the individuals carrying the CCR5Delta32 59537-G/G genotype. The results imply that the absence of CCR5Delta32 protein in two HIV(+) individuals is due to a genetic defect in the translation of the protein. Together, these results highlight the importance of the CCR5Delta32 protein as an HIV suppressive factor and provide further insight into the mechanism of the protective effect of the CCR5Delta32 mutation.
我们最近证实，CCR5Delta32蛋白与CCR5和CXCR4相互作用，并下调它们在细胞表面的表达。我们还报告称，在6名感染人类免疫缺陷病毒（HIV(+)）的CCR5(-/-)个体中，有4名未检测到截短的CCR5Delta32蛋白表达。为了解释这些样本中蛋白质表达的缺陷，我们对这6名HIV(+)个体的启动子区域进行了克隆和测序。我们在CCR5Delta32启动子区域发现了几种多态性，但这些多态性与mRNA水平的显著差异无关。体外转录/翻译偶联和多核糖体分析表明，一种名为CCR5Delta32 59537-A/A的变异基因型与低翻译效率之间存在密切关联。蛋白质分析表明，与携带CCR5Delta32 59537-G/G基因型的个体相比，两名携带CCR5Delta32 59537-A/A变异的HIV(+) CCR5(-/-)个体的外周血单核细胞表达的CCR5Delta32蛋白量极少。结果表明，两名HIV(+)个体中CCR5Delta32蛋白的缺失是由于该蛋白翻译过程中的遗传缺陷。总之，这些结果突出了CCR5Delta32蛋白作为一种HIV抑制因子的重要性，并为CCR5Delta32突变的保护作用机制提供了进一步的见解。
