Chakrabarti L A, Luckay A, Marx P A
Aaron Diamond AIDS Research Center, Rockefeller University, New York, New York 10016,
AIDS Res Hum Retroviruses. 2001 Aug 10;17(12):1155-65. doi: 10.1089/088922201316912763.
SIVsm, the simian immunodeficiency virus that naturally infects sooty mangabeys in West Africa, is the closest lentiviral relative of human immunodeficiency virus type 2 (HIV-2). To determine the genetic characteristics of SIVsm in its natural host, we sequenced the full-length genome of SIVsmSL92b, a primary isolate obtained from a pet sooty mangabey in Sierra Leone. SIVsmSL92b proved to be the most divergent member of the HIV-2/SIVsm lineage found thus far, having as much as 35% nucleotide divergence from other HIV-2 genomes. A phylogenetic association between SIVsmSL92b and HIV-2 PA subtype E, which had been previously revealed by the analysis of partial gag sequences, was extended to the pol gene. SIVsmSL92b showed several divergent features, including a short Tat protein of 104 residues and an atypical TAR structure. Specifically, only one of the duplicate TAR elements contained the conserved hexanucleotide loop sequence CUGGGX important for Tat-cyclin T1 binding. These features suggested that the mechanism of SIVsmSL92b Tat and TAR interaction differed from that described for HIV-2. Taken together, these findings indicated that the structural diversity within the HIV-2/SIVsm lineage was greater than previously appreciated.
SIVsm是一种自然感染西非乌黑白眉猴的猿猴免疫缺陷病毒，是人类免疫缺陷病毒2型（HIV-2）最接近的慢病毒亲属。为了确定SIVsm在其天然宿主中的遗传特征，我们对SIVsmSL92b的全长基因组进行了测序，SIVsmSL92b是从塞拉利昂一只宠物乌黑白眉猴身上获得的原始分离株。SIVsmSL92b被证明是迄今为止发现的HIV-2/SIVsm谱系中差异最大的成员，与其他HIV-2基因组的核苷酸差异高达35%。之前通过对部分gag序列的分析揭示的SIVsmSL92b与HIV-2 PA亚型E之间的系统发育关联扩展到了pol基因。SIVsmSL92b表现出几个不同的特征，包括一个由104个残基组成的短Tat蛋白和一个非典型的TAR结构。具体来说，重复的TAR元件中只有一个包含对Tat-细胞周期蛋白T1结合很重要的保守六核苷酸环序列CUGGGX。这些特征表明，SIVsmSL92b的Tat与TAR相互作用机制与HIV-2中描述的不同。综上所述，这些发现表明HIV-2/SIVsm谱系内的结构多样性比之前认为的更大。
