School of Chemical and Biological Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 151-744, Korea.
Mol Microbiol. 2013 Jun;88(6):1120-34. doi: 10.1111/mmi.12246. Epub 2013 May 16.
Aro80, a member of the Zn(2)Cys(6) family proteins, activates expression of the ARO9 and ARO10 genes involved in catabolism of aromatic amino acids in response to aromatic amino acids that act as inducers. ARO9 and ARO10 are also under the control of nitrogen catabolite repression, but the direct roles for GATA factors, Gat1 and Gln3, in this regulation have not yet been elucidated. Here, we demonstrate that Aro80 is constitutively bound to its target promoters and activated by inducers at the level of transactivation. Although Aro80 also binds to its own promoter, ARO80 expression is induced only by rapamycin, but not by tryptophan. We show that Aro80 is absolutely required for Gat1 binding to the ARO9, ARO10 and ARO80 promoters upon rapamycin treatment. Gln3 binding to these promoters shows a partial requirement for Aro80. Rapamycin-dependent Gat1 and Gln3 binding to the Aro80 target promoters is not affected by tryptophan availability, suggesting that transactivation activity of Aro80 is not necessary for the recruitment of GATA factors. Rapamycin-dependent induction of Aro80 target genes also requires PP2A phosphatase complex, but not Sit4 phosphatase, acting downstream of TORC1.
Aro80 是 Zn(2)Cys(6)家族蛋白的成员，可响应作为诱导物的芳香族氨基酸激活参与芳香族氨基酸分解代谢的 ARO9 和 ARO10 基因的表达。ARO9 和 ARO10 也受氮分解代谢物抑制的控制，但 GATA 因子 Gat1 和 Gln3 在这种调节中的直接作用尚未阐明。在这里，我们证明 Aro80 与它的靶启动子持续结合，并在转录激活水平上被诱导物激活。虽然 Aro80 也与自身启动子结合，但 ARO80 的表达仅在 rapamycin 存在时被诱导，而不是在色氨酸存在时被诱导。我们表明，在 rapamycin 处理时，Aro80 绝对需要 Gat1 结合到 ARO9、ARO10 和 ARO80 启动子上。Gln3 结合到这些启动子上需要 Aro80 的部分。Rapamycin 依赖性 Gat1 和 Gln3 结合到 Aro80 靶启动子不受色氨酸可用性的影响，表明 Aro80 的转录激活活性对于 GATA 因子的募集不是必需的。Rapamycin 依赖性 Aro80 靶基因的诱导也需要 PP2A 磷酸酶复合物，但不需要 Sit4 磷酸酶，该酶作用于 TORC1 的下游。
