Molecular cloning and characterization of cellular factors which associate with HIV-1 activation

为了确定与HIV-1激活相关的细胞因子，我们分离了7个具有TAR RNA结合特性的克隆。数据库检索结果显示，5个克隆分别鉴定为核因子90 （NF90）、聚a结合蛋白之一、酵母35.1kDa蛋白的人类同源物、鸡内着丝粒蛋白的人类同源物和小鼠磷酸化蛋白p150的人类同源物。剩下的2个克隆还没有被确定。NF90是活化t细胞产生白细胞介素-2所必需的，它有两个结构域，其中包含与TAR RNA结合蛋白（TRBP）等共同的双链RNA结合基元。TRBP是第一个被发现的编码TAR rna结合蛋白的基因。因此，我们的筛选条件似乎适合从lambdagt11载体构建的cDNA文库中筛选TAR rna结合蛋白。对克隆27（酵母35.1kDa蛋白的人类同源物JTR27）进行了全长cDNA测序，并对其性状进行了研究。JTR27反义寡核苷酸在存在或不存在Tat的情况下均能抑制HIV-1 ltr定向基因的表达。过表达JTR27不仅显著增强了HIV-1 LTR基础转录，而且显著增强了tat活化。综合这些结果，提示JTR27与HIV-1LTR基因表达有关。

To identify cellular factors which associate with HIV-1 activation, we have isolated 7 clones with their TAR RNA binding properties. Data base search revealed that 5 clones were identified as a nuclear factor 90 (NF90), one of poly A binding proteins, a human homologue of yeast 35.1kDa protein, a human homologoue of chicken inner centromere protein, and a human homologue of mouse phosphoprotein p150, respectively. The remaining 2 clones have not been identified. NF90, which is indispensable for activated T-cells to produce interleukin-2, has two domains, which contains a double-stranded RNA binding motif common to such as TAR RNA-binding protein (TRBP). TRBP is the first identified gene encoding a TAR RNA-binding protein. Thus, our screening conditions are seemed to be suitable for screening of TAR RNA-binding proteins from cDNA libraries constructed by the lambdagt11 vector. As for clone 27 (JTR27 ; a human homologue of yeast 35.1kDa protein), its full-length cDNA was sequenced and its characters were investigated. JTR27 antisense oligonucleotide repressed HIV-1 LTR-directed gene expression either in the presence or absence of Tat. Overexpression of JTR27 significantly augmented not only the HIV-1 LTR basal transcription but also Tat-activation. Taken together these results, it was suggested that JTR27 associates with HIV-1LTR gene expression.