Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas/Universidad de Salamanca, 37007 Salamanca, Spain.
Mol Biol Cell. 2012 Nov;23(21):4297-312. doi: 10.1091/mbc.E12-04-0331. Epub 2012 Sep 12.
The transcriptional coactivator Sub1 has been implicated in several steps of mRNA metabolism in yeast, such as the activation of transcription, termination, and 3'-end formation. In addition, Sub1 globally regulates RNA polymerase II phosphorylation, and most recently it has been shown that it is a functional component of the preinitiation complex. Here we present evidence that Sub1 plays a significant role in transcription elongation by RNA polymerase II (RNAPII). We show that SUB1 genetically interacts with the gene encoding the elongation factor Spt5, that Sub1 influences Spt5 phosphorylation of the carboxy-terminal domain of RNAPII largest subunit by the kinase Bur1, and that both Sub1 and Spt5 copurify in the same complex, likely during early transcription elongation. Indeed, our data indicate that Sub1 influences Spt5-Rpb1 interaction. In addition, biochemical and molecular data show that Sub1 influences transcription elongation of constitutive and inducible genes and associates with coding regions in a transcription-dependent manner. Taken together, our results indicate that Sub1 associates with Spt5 and influences Spt5-Rpb1 complex levels and consequently transcription elongation rate.
转录共激活因子 Sub1 被认为参与了酵母中 mRNA 代谢的几个步骤，如转录激活、终止和 3'端形成。此外，Sub1 还全局调节 RNA 聚合酶 II 的磷酸化，最近的研究表明它是起始前复合物的一个功能成分。在这里，我们提供了证据表明 Sub1 在 RNA 聚合酶 II (RNAPII) 的转录延伸中起着重要作用。我们表明 SUB1 与编码延伸因子 Spt5 的基因在遗传上相互作用，Sub1 影响激酶 Bur1 对 RNAPII 大亚基羧基末端结构域的 Spt5 磷酸化，并且 Sub1 和 Spt5 都在同一个复合物中共同纯化，可能在早期转录延伸过程中。事实上，我们的数据表明 Sub1 影响 Spt5-Rpb1 相互作用。此外，生化和分子数据表明，Sub1 影响组成型和诱导型基因的转录延伸，并以依赖转录的方式与编码区结合。总之，我们的结果表明，Sub1 与 Spt5 相关，并影响 Spt5-Rpb1 复合物的水平，从而影响转录延伸率。
