Hsiao P W, Chang C
Departments of Pathology, Urology, and Radiation Oncology, George Whipple Laboratory for Cancer Research, University of Rochester, Rochester, New York 14642, USA.
J Biol Chem. 1999 Aug 6;274(32):22373-9. doi: 10.1074/jbc.274.32.22373.
The androgen receptor (AR) is a member of the steroid receptor superfamily that may require coactivators for proper or maximal transactivation. Using a purified AR N-terminal peptide as a probe to screen the human testis expression library, we identified an androgen-enhanced AR N-terminal-associated protein ARA160, which consists of 1,093 amino acids with an apparent molecular mass of 160 kDa. Sequence comparison in GenBank(TM) reveals that ARA160 shares an identical sequence with a HIV-1 TATA element modulatory factor, TMF. The far-Western blotting and co-immunoprecipitation assays demonstrate that the AR can interact directly with ARA160/TMF. Affinity gel pull-down and mammalian two-hybrid assays further suggest androgen can enhance significantly the interaction between AR and ARA160. Transient transfection assays demonstrated that ARA160 might function as a coactivator for AR-mediated transactivation in human prostate cancer PC-3 cells. Our data further suggest that this AR N-terminal coactivator can function cooperatively with AR C-terminal coactivator, ARA70, in PC-3 cells. Together, our data demonstrate that ARA160 might represent the first identified androgen-enhanced N-terminal coactivator for the AR.
雄激素受体（AR）是类固醇受体超家族的成员，可能需要共激活因子来实现适当或最大程度的反式激活。我们使用纯化的AR N端肽作为探针筛选人睾丸表达文库，鉴定出一种雄激素增强的AR N端相关蛋白ARA160，它由1093个氨基酸组成，表观分子量为160 kDa。在GenBank(TM)中的序列比较显示，ARA160与HIV-1 TATA元件调节因子TMF具有相同的序列。远缘Western印迹和共免疫沉淀分析表明，AR可直接与ARA160/TMF相互作用。亲和凝胶下拉和哺乳动物双杂交分析进一步表明，雄激素可显著增强AR与ARA160之间的相互作用。瞬时转染分析表明，ARA160可能在人前列腺癌PC-3细胞中作为AR介导的反式激活的共激活因子发挥作用。我们的数据进一步表明，这种AR N端共激活因子可在PC-3细胞中与AR C端共激活因子ARA70协同发挥作用。总之，我们的数据表明，ARA160可能是首个被鉴定出的AR的雄激素增强N端共激活因子。
