Gomar-Alba M, Del Olmo M
Departament de Bioquímica i Biologia Molecular, Facultat de Ciències Biològiques, Universitat de València, Dr. Moliner, 50, Burjassot, Valencia E-46100, Spain.
Biochem J. 2016 Oct 1;473(19):3065-79. doi: 10.1042/BCJ20160463. Epub 2016 Aug 1.
Hyperosmotic stress response involves the adaptative mechanisms needed for cell survival. Under high osmolarity conditions, many stress response genes are activated by several unrelated transcription factors that are controlled by the Hog1 kinase. Osmostress transcription factor Hot1 regulates the expression of several genes involved in glycerol biosynthesis, and the presence of this transcription factor in their promoters is essential for RNApol II recruitment. The physical association between Hog1 and Hot1 activates this transcription factor and directs the RNA polymerase II localization at these promoters. We, herein, demonstrate that physical and genetic interactions exist between Hot1 and several proteins involved in transcriptional and posttranscriptional processes: for example, transcription co-activator Sub1 and elongation complex Spt4/5. The results presented in this work demonstrate that Hot1 enrichment is not detected through the coding regions of its target genes and rule out a direct role in transcription elongation. Instead, other data presented herein indicate a key function of the Hot1 transcription factor in the recruitment of these proteins to the promoter or the 5'-coding region of the genes under its control.
高渗应激反应涉及细胞存活所需的适应性机制。在高渗透压条件下，许多应激反应基因由几种不相关的转录因子激活，这些转录因子受Hog1激酶调控。渗透压应激转录因子Hot1调节参与甘油生物合成的几个基因的表达，其启动子中该转录因子的存在对于RNA聚合酶II的募集至关重要。Hog1与Hot1之间的物理相互作用激活该转录因子，并指导RNA聚合酶II在这些启动子处的定位。我们在此证明，Hot1与参与转录和转录后过程的几种蛋白质之间存在物理和遗传相互作用：例如，转录共激活因子Sub1和延伸复合物Spt4/5。这项工作中呈现的结果表明，在其靶基因的编码区域未检测到Hot1富集，并排除了其在转录延伸中的直接作用。相反，本文呈现的其他数据表明，Hot1转录因子在将这些蛋白质募集到其控制下的基因的启动子或5'编码区域中具有关键功能。
