RNA Polymerase II Carboxyl-terminal Domain Phosphorylation Regulates Protein Stability of the Set2 Methyltransferase and Histone H3 Di- and Trimethylation at Lysine 36
RNA Polymerase II Carboxyl-terminal Domain Phosphorylation Regulates Protein Stability of the Set2 Methyltransferase and Histone H3 Di- and Trimethylation at Lysine 36
复制标题
DOI：
10.1074/jbc.m111.273953
复制
发表时间：
2012-01-27
影响因子：
4.8
通讯作者：
Strahl, Brian D.
中科院分区：
文献类型：
--
作者：
Fuchs, Stephen M.;Kizer, Kelby O.;Strahl, Brian D.
组蛋白H3（H3 K36）上赖氨酸36的甲基化由Set 2甲基转移酶催化，并与转录调控有关。先前的研究表明，通过Set 2的H3 K36的三甲基化是通过其与RNA聚合酶C-末端结构域（RNAPII CTD）的磷酸化重复的缔合来指导的。在这里，我们表明，通过使用CTD磷酸化缺陷的酵母突变体在丝氨酸2导致Set 2蛋白水平和H3 K36甲基化的不稳定，这种相互作用的中断。与此一致，我们发现Set 2具有短的半衰期，并且在酵母的对数生长期间与RNAPII CTD磷酸化水平共调节。为了探测解偶联Set 2-RNAPII调节的功能后果，我们表达了截短的且更稳定的Set 2形式，其能够在体内二甲基化但不能三甲基化。高通量合成遗传分析的结果表明，该Set 2变体具有与SET 2或set 2 Delta不同的遗传学，并且具有许多转录延伸突变体，是合成性致病或致死的。总的来说，这些结果提供了对影响H3 K36甲基化状态的Set 2蛋白水平的调节的分子见解。
Methylation of lysine 36 on histone H3 (H3K36) is catalyzed by the Set2 methyltransferase and is linked to transcriptional regulation. Previous studies have shown that trimethylation of H3K36 by Set2 is directed through its association with the phosphorylated repeats of the RNA polymerase C-terminal domain (RNAPII CTD). Here, we show that disruption of this interaction through the use of yeast mutants defective in CTD phosphorylation at serine 2 results in a destabilization of Set2 protein levels and H3K36 methylation. Consistent with this, we find that Set2 has a short half-life and is co-regulated, with RNAPII CTD phosphorylation levels, during logarithmic growth in yeast. To probe the functional consequence of uncoupling Set2-RNAPII regulation, we expressed a truncated and more stable form of Set2 that is capable of dimethylation but not trimethylation in vivo. Results of high throughput synthetic genetic analyses show that this Set2 variant has distinct genetics from either SET2 or set2 Delta and is synthetically sick or lethal with a number of transcription elongation mutants. Collectively, these results provide molecular insight into the regulation of Set2 protein levels that influence H3K36 methylation states.