ADC及非ADC患者外周和中枢HIV-1 tat基因多样性分析

Analysis of genetic diversity and amino acid sequence of HIV-ltat in CNS and peripheral tissue of a patient with ADC and a patient with non-ADC

目的 研究艾滋病痴呆综合征（ADC）及非ADC患者外周和中枢神经系统（CNS） HIV-1 tat基因的多样性，为HIV进化、入侵CNS的机制以及ADC发病机制研究提供依据。方法 提取一例非ADC患者（有广泛的脑动脉粥样硬化）及一例ADC患者尸检标本的外周脾脏和CNS基底核部位的基因组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、氨苄西林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）,研究HIV tat基因在外周和CNS的多样性。结果 ADC和非ADC患者来源的HIV-1 tat基因均存在变异，ADC患者tat基因进化时中枢和外周的区室化效应明显高于非ADC患者，ADC患者外周脾脏和CNS基底核的tat基因之间的差异比非ADC患者更大。dn/ds值显示，两例患者体内HIV-1自身变异起主要作用，而机体倾向于清除有害的非同义突变。结论 ADC和非ADC患者外周和CNS中tat基因变异的区室化效应不同，其原因推测与病毒入侵CNS的途径有关,CNS中HIV基因变异与ADC的关系仍需进一步研究。

Objective To study the diversity of HIV-1 tat gene in CNS and peripheral tissue of a patient with ADC and a patient with non-ADC, so as to research HIV evolution, the mechanism of CNS invasion and the pathogenesis of ADC. Methods The tat gene was amplified with nested PCR from genomic DNA which was extracted from spleen and basal ganglia of one non-ADC patient with a wide range of cerebral artery atherosclerosis and one ADC patient. 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, pdistances, values of ds/dn, and analysis of amino acid motifs were all done, so as to research the diversity of HIV-1 tat gene in CNS and peripheral tissue. Results Gene mutation of HIV-1 tat exist in the two patients,the mutation process of tat isolated from ADC patient suffered more compartmentalization than tat isolated from non-ADC patient, the differences of tat genes between CNS and peripheral tissue in ADC patient were greater than the non-ADC patient. Ds/dn showed that the virus gene mutation played a major role, the body intend to remove harmful non-synonymous mutations. ConclusionsThe compartmentation of tat gene in CNS and peripheral tissue of the two patients was different, the reason may be related to the pathway of HIV into the CNS, the relationship between HIV gene mutation in CNS and ADC still need more investigation.