Fcp1 Dephosphorylation of the RNA Polymerase II C-Terminal Domain Is Required for Efficient Transcription of Heat Shock Genes
Fcp1 Dephosphorylation of the RNA Polymerase II C-Terminal Domain Is Required for Efficient Transcription of Heat Shock Genes
复制标题
RNA 聚合酶 II C 端结构域的 Fcp1 去磷酸化是热休克基因有效转录所必需的
DOI：
10.1128/mcb.00247-12
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发表时间：
2012-09-01
影响因子：
5.3
通讯作者：
Lisa, John T.
中科院分区：
文献类型：
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作者：
Fuda, Nicholas J.;Buckley, Martin S.;Lisa, John T.
Fcp1使RNA聚合酶II （Pol II）最大亚基的c端结构域去磷酸化，将其再循环成一种可以启动新一轮转录的形式。之前，我们发现果蝇Fcp1是热休克后Hsp70 mRNA积累的重要因素。在这里，我们研究了Fcp1在体内热休克基因转录中的作用。我们证明Fcp1定位于转录的活性位点，包括诱导的Hsp70基因。S2细胞中Fcp1的RNA干扰（RNAi）缺失导致Hsp70 mRNA积累减少，这是由于热休克诱导的高转录基因Hsp70、Hsp26和Hsp83编码区Pol II缺失所致。此外，Fcp1的缺失显著增加了非染色质结合的Pol II的磷酸化。无论是野生型还是催化死亡版本的Fcp1的重新表达都表明，热休克基因上Pol II水平的降低和磷酸化的游离Pol II水平的增加都依赖于Fcp1的催化活性。我们的研究结果表明，Fcp1需要维持启动能力的非磷酸化Pol II的池，这一功能对高度转录的热休克基因尤其重要。
ABSTRACT Fcp1 dephosphorylates the C-terminal domain of the largest subunit of RNA polymerase II (Pol II) to recycle it into a form that can initiate a new round of transcription. Previously, we identified Drosophila Fcp1 as an important factor in optimal Hsp70 mRNA accumulation after heat shock. Here, we examine the role of Fcp1 in transcription of heat shock genes in vivo. We demonstrate that Fcp1 localizes to active sites of transcription including the induced Hsp70 gene. The reduced Hsp70 mRNA accumulation seen by RNA interference (RNAi) depletion of Fcp1 in S2 cells is a result of a loss of Pol II in the coding region of highly transcribed heat shock-induced genes: Hsp70, Hsp26, and Hsp83. Moreover, Fcp1 depletion dramatically increases phosphorylation of the non-chromatin-bound Pol II. Reexpression of either wild-type or catalytically dead versions of Fcp1 demonstrates that both the reduced Pol II levels on heat shock genes and the increased levels of phosphorylated free Pol II are dependent on the catalytic activity of Fcp1. Our results indicate that Fcp1 is required to maintain the pool of initiation-competent unphosphorylated Pol II, and this function is particularly important for the highly transcribed heat shock genes.