医学检验信息网 检验医学 2007-2-11 13:02:21

关键词: 人类免疫缺陷病毒1型；tat基因；序列分析；B亚型；C亚型 【摘要】 目的 人类免疫缺陷病毒1型(HIV-1)tat基因是该病毒的调控基因之一。本研究是探讨tat基因变异是否影响HIV－1感染者的病程进展。方法 从云南HIV流行区的22例HIV感染后临床进程不同的人抽取外周血，提取核酸，用套式聚合酶链反应(PCR)扩增HIV-1的tat基因，并进行了核酸序列测定和分析。结果 22个HIV毒株中，有11株来自长期不进展者，均为B亚型。另外11株来自一般感染者的HIV毒株，5株为B亚型，6株为C亚型。长期不进展者和HIV-1 b亚型一般感染者的tat基因序列与国际B亚型共享序列比较，两组均在相同的固定的4个位点上氨基酸与共享序列不一致。在系统树分析中两组亦聚集在一起，未显示出分离。C亚型一般感染者的tat基因序例组内变异小，在固定的6个位点上与国际C亚型共享序列不一致。结论 长期不进展者与一般B亚型感染者的Tat蛋白序例均未发现规律性差异。HIV感染后的进展速率可能与HIV-1tat基因序例无明显关系。 Sequence analysis of human immunodeficiency virus type 1 tat gene among the long term HIV infected non-progressoris in Yunnan Province ZHAO feng, SHAO Yiming, DUAN Yijuan, et al.Institute of Virology, Chinese Academy of preventive Medicine, Beijing 100052 【Abstract】 Objective HIV-1 tat gene is one of its regulatory genes necessary for its riplication. This study is to explore whether the variation of tat gene influences the AIDS progress of HIV infectect individual.Methods We carried out investigation on tat gene of HIV among the long term HIV infected non-progressors and the commonly infected individuals. Mononuclear cells of peripheral blood were isolated and cellular DNA was extracted. Nested PCR method was used to amplify tat gene and their sequences were analyzed.Results Blood were collected from 22 HIV infected individuals, of which 11 cases were infected with B subtype strains based on previous env gene analysis and belonged to long term non-progressors according to clinical features and immunology. The other11 cases were common HIV infection of which 5 subtype B and 6 subtype C were found. both long term non-progressor group (subtype B) and the commonly HIV infectedly group (subtype B) had constantly four amino acids different from that of international b subtype consensus sequence The both groups clusteed randomly on the phylogenetic tree. In commonly HIV infected subtype C group there were 6 amino acids different from that of international subtype C. The variation inside the tatgene of common subtype C group was small.Conclusions There was no regular variation and significant difference between long term HIV infected non-progressve group and commonly HIV infected subtype B group. There is no evidence showing that progressive speed of AIDS correlated with the tat sequence profile of HIV-1. 【Key words】 Human immunodeficiency virus type 1 tat gene Sequence analysis Subtype B Subtype C HIV1的tat基因是该病毒的调控基因之一，是病毒复制所必需。它通过反式激活方式作用于转录产物RNA的5'端的TAR区，从而提高病毒RNA的水平^［1，2］。tat基因包括两个外显子，第一外显子包含72个密码子，第二外显子则随翻译终止密码子的位置不同使Tat蛋白变化于86至130个氨基酸之间，两外显子之间间隔约2.3 kb^［3］。已有的突变分析表明，第二外显子无任何功能，缺失该区域的Tat蛋白各种功能完全正常^［4］。既然tat基因是HIV复制所必需，tat基因的变异必然影响到病毒的复制，影响病毒的生物学特性，比如体外培养特性，感染者体内的病毒载量，感染者的潜伏期等。tat的严重缺失或突变则有可能使病毒完全不复制，这对于研究HIV减毒活疫苗能够提供帮助。 自HIV于80年代初传入我国以来，在云南某些地区HIV已有约10年的流行史，一些早期的HIV感染者目前仍存活(长期不进展者)，同时也不断有新的感染者出现。为阐明tat基因与HIV生物学特性之间的关系及该地区HIV-1 tat基因的变异状况，我们采集了该地区HIV感染的长期不进展者及一般感染者的外周血，克隆了其HIV-1 tat基因的第一外显子并进行了序列分析。 1 材料和方法

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