Transcriptional activator Tax of HTLV-1 binds to the NF-kappa B precursor p105.
Transcriptional activator Tax of HTLV-1 binds to the NF-kappa B precursor p105.
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HTLV-1 的转录激活剂 Tax 与 NF-κ B 前体 p105 结合。
作者：
H. Hirai;J. Fujisawa;T. Suzuki;K. Ueda;M. Muramatsu;A. Tsuboi;N. Arai;M. Yoshida
人类t细胞白血病病毒1型（HTLV-1）诱导成人t细胞白血病，也是一种神经系统疾病，热带痉挛性截瘫。HTLV-1的Tax蛋白（p40tax）在长末端重复序列中反式激活自身转录增强子，也激活白细胞介素2受体α、粒细胞-巨噬细胞集落刺激因子、Fos、Jun和MHC类i等细胞基因中的转录增强子。因此，人们认为Tax在HTLV-1感染诱导的发病机制中起关键作用。在这里，我们报道了与NF-kappa B p50亚基的前体蛋白p105形成的Tax蛋白复合物。在转染了Tax表达质粒的HTLV-1感染细胞中，p105与Tax蛋白共免疫沉淀，而在转染了无活性Tax突变体的细胞中，p105与Tax蛋白共免疫沉淀。此外，大肠杆菌中产生的GST-p105融合蛋白与Tax蛋白结合。这些结果强烈提示反式激活子Tax蛋白与前体NF-kappa B p105形成复合物，并在转录起始的反式激活中发挥作用。
Human T-cell leukemia virus type 1 (HTLV-1) induces adult T-cell leukemia and also a neurological disease, tropical spastic paraparesis. Tax protein (p40tax) of HTLV-1 activates in trans its own transcriptional enhancer in the long terminal repeat and also those in some cellular genes such as interleukin 2 receptor alpha, granulocyte-macrophage colony-stimulating factor, Fos, Jun and MHC class I. Thus, Tax has been proposed to play a critical role in the pathogenesis induced by HTLV-1 infection. Here, we report formation of a complex of Tax protein with the precursor protein p105 of the NF-kappa B p50 subunit. p105 was co-immunoprecipitated with Tax protein from cells infected with HTLV-1 from cells transfected with the Tax expression plasmid, but not from cells transfected with inactive mutants of Tax. Furthermore, a GST-p105 fusion protein produced in Escherichia coli bound to Tax protein. These results strongly suggest that the trans-activator Tax protein forms a complex with precursor NF-kappa B p105 and plays a role in trans-activation of transcriptional initiation.