Li Meng, Liu Pengcheng, Wiley Jessica D, Ojani Reyhaneh, Bevan David R, Li Jianyong, Zhu Jinsong
Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA.
Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA.
Mol Cell Endocrinol. 2014 Aug 25;394(1-2):47-58. doi: 10.1016/j.mce.2014.06.021. Epub 2014 Jul 6.
Methoprene-tolerant (Met) protein is a juvenile hormone (JH) receptor in insects. JH-bound Met forms a complex with the βFtz-F1-interacting steroid receptor coactivator (FISC) and together they regulate JH response genes in mosquitoes. Both proteins contain basic helix-loop-helix (bHLH) and PAS motifs. Here we demonstrated that FISC is the obligatory partner of Met for binding to JH-response elements (JHREs). Met or FISC alone could not bind a previously characterized JHRE, while formation of the Met-FISC complex was necessary and sufficient to bind to the JHRE. This binding required participation of the DNA-binding domains of both Met and FISC. The optimal DNA sequence recognized by Met and FISC contained a core consensus sequence GCACGTG. While formation of the Met-FISC complex in mosquito cells was induced by JH, heterodimerization and DNA binding of bacterially expressed Met and FISC were JH-independent, implying that additional mosquito proteins were required to modulate formation of the receptor complex.
耐甲氧普烯（Met）蛋白是昆虫中的一种保幼激素（JH）受体。与JH结合的Met与βFtz-F1相互作用类固醇受体共激活因子（FISC）形成复合物，它们共同调节蚊子中的JH反应基因。这两种蛋白质都含有碱性螺旋-环-螺旋（bHLH）和PAS基序。在这里，我们证明FISC是Met与JH反应元件（JHREs）结合的必需伴侣。单独的Met或FISC都不能结合先前鉴定的JHRE，而Met-FISC复合物的形成对于结合JHRE是必要且充分的。这种结合需要Met和FISC的DNA结合结构域的参与。Met和FISC识别的最佳DNA序列包含核心共有序列GCACGTG。虽然JH诱导蚊子细胞中Met-FISC复合物的形成，但细菌表达的Met和FISC的异二聚化和DNA结合不依赖于JH，这意味着需要额外的蚊子蛋白质来调节受体复合物的形成。
