Osmostress-induced transcription by Hot1 depends on a Hog1-mediated recruitment of the RNA Pol II
Osmostress-induced transcription by Hot1 depends on a Hog1-mediated recruitment of the RNA Pol II
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DOI：
10.1093/emboj/cdg243
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发表时间：
2003-05-15
期刊：
影响因子：
11.4
通讯作者：
Posas, F
中科院分区：
文献类型：
--
作者：
Alepuz, PM;de Nadal, E;Posas, F
在芽殖酵母中，丝裂原激活蛋白激酶 (MAPK) Hog1 协调细胞在渗透压下生存所需的转录程序。 Hot1 转录因子在 MAPK 下游发挥作用，调节 Hog1 响应基因的子集。为了应对高渗透压，Hot1 将 Hog1 靶向特定的渗透压响应启动子。在这里，我们证明了 Hot1 依赖性启动子上通用转录机制的组装取决于 Hot1 和活性 Hog1 MAPK 的存在。出乎意料的是，RNA 聚合酶 (Pol) II 复合物向靶启动子的募集并不依赖于 MAPK 对 Hot1 激活剂的磷酸化。 Hog1 与 RNA Pol II 以及转录机制的一般组件相互作用。此外，当作为 LexA 融合蛋白连接到启动子时，Hog1 以应激调节的方式激活转录。因此，Hot1 激活剂将活性 Hog1 锚定到启动子对于 RNA Pol II 的招募和激活至关重要。哺乳动物 p38 还与 RNA Pol II 相互作用，这可能表明真核细胞中 SAPK 调节基因表达的保守机制。
In budding yeast, the mitogen-activated protein kinase (MAPK) Hog1 coordinates the transcriptional program required for cell survival upon osmostress. The Hot1 transcription factor acts downstream of the MAPK and regulates a subset of Hog1-responsive genes. In response to high osmolarity, Hot1 targets Hog1 to specific osmostress-responsive promoters. Here, we show that assembly of the general transcription machinery at Hot1-dependent promoters depends on the presence of Hot1 and active Hog1 MAPK. Unexpectedly, recruitment of RNA polymerase (Pol) II complex to target promoters does not depend on the phosphorylation of the Hot1 activator by the MAPK. Hog1 interacts with the RNA Pol II and with general components of the transcription machinery. More over, when tethered to a promoter as a LexA fusion protein, Hog1 activates transcription in a stress- regulated manner. Thus, anchoring of active Hog1 to promoters by the Hot1 activator is essential for recruitment and activation of RNA Pol II. The mammalian p38 also interacts with the RNA Pol II, which might suggest a conserved mechanism for regulation of gene expression by SAPKs among eukaryotic cells.