艾滋病痴呆综合征病人HIV-1tat基因多态性及氨基酸序列分析

目的 研究艾滋病痴呆综合征患者体内HIV-1 tat第一外显子基因序列的特征和变异情况,为艾滋病痴呆综合征发病机制的研究提供依据.方法 提取1例艾滋病痴呆综合征病例尸检标本的外周组织(淋巴结、脾脏)和中枢神经组织(脑膜、额叶灰质、额叶白质、颞叶、基底核)共7个部位的基因组DNA,巢式PCR扩增HIV-1 tat第一外显子基因,与克隆载体pGEM-T连接,经转化、氨苄青霉素和蓝白斑筛选出阳性克隆,每个部位挑取5个菌落测序,测序结果利用BioEdit、MEGA4软件比对并生成系统进化树、计算基因距离和同义/非同义替换值(ds/dn),分析氨基酸位点的改变.结果 该病例感染的病毒是HIV-1 B亚型,分离自不同组织的HIV-1 tat第一外显子基因序列存在差异;与标准序列相比,该病例的HIV-1tat第一外显子基因编码的氨基酸序列有16个位点发生了变异,并且中枢各部位部分氨基酸位点的变异与外周不同,特别是中枢基底核5个序列及颞叶1个序列Q54R的变异值得关注.结论 艾滋病痴呆综合征患者体内,HIV-1 tat第一外显子序列与标准序列存在差异,并且在外周和中枢不同部位中存在的变异不同,这些变异是否与艾滋病痴呆综合征的发病机制有关,还有待进一步研究.

Abstract：

Objective To study the variation and characteristics of HIV-1 tat exon 1 gene from a patient with AIDS dementia complex( ADC), so as to research the pathogenesis of ADC. Methods The tat gene was amplified with nested PCR from genomic DNA which was extracted from lymph node, spleen and different brain tissues( meninges, grey matter from frontal cortex, white matter from frontal cortex, temporal cortex and basal ganglia) of a patient who died of ADC. PCR products were cloned into the pGEM-T vector,after transformation and selection by ampicillin and blue/white spotting. Five of positive clones were sequenced. HIV-1 tat sequences were processed with BioEdit and MEGA4. With the softwares, Neighbor-Joining tree, p-Distances, values of ds/dn, and analysis of amino acid motifs were all done. Results The samples were all identified as HIV-1 B and genetic variation exists in HIV-1 tat isolated from different tissue;Compared with HXB2, sixteen sites of the amino acid seque nce coded by the HIV-1 tat gene which was isolated from the patient changed. In addition, part of the changes were different between periphery and brain,especially, the five Q54R changes from basal ganglia and one Q54R change from temporal cortex are deserve to follow with interest. Conclusion Variations exist in the HIV-1 tat genes extracted from the ADC patient and the variations from peripheral and central nerve tissues were different, whether the variations concerned with the pathogenesis of ADC need more research.

Analysis of genetic diversity and amino acid sequence of HIV-1 tat from a patient with AIDS dementia complex

Objective To study the variation and characteristics of HIV-1 tat exon 1 gene from a patient with AIDS dementia complex( ADC), so as to research the pathogenesis of ADC. Methods The tat gene was amplified with nested PCR from genomic DNA which was extracted from lymph node, spleen and different brain tissues( meninges, grey matter from frontal cortex, white matter from frontal cortex, temporal cortex and basal ganglia) of a patient who died of ADC. PCR products were cloned into the pGEM-T vector,after transformation and selection by ampicillin and blue/white spotting. Five of positive clones were sequenced. HIV-1 tat sequences were processed with BioEdit and MEGA4. With the softwares, Neighbor-Joining tree, p-Distances, values of ds/dn, and analysis of amino acid motifs were all done. Results The samples were all identified as HIV-1 B and genetic variation exists in HIV-1 tat isolated from different tissue;Compared with HXB2, sixteen sites of the amino acid seque nce coded by the HIV-1 tat gene which was isolated from the patient changed. In addition, part of the changes were different between periphery and brain,especially, the five Q54R changes from basal ganglia and one Q54R change from temporal cortex are deserve to follow with interest. Conclusion Variations exist in the HIV-1 tat genes extracted from the ADC patient and the variations from peripheral and central nerve tissues were different, whether the variations concerned with the pathogenesis of ADC need more research.