Pin1 modulates RNA polymerase II activity during the transcription cycle.
Pin1 modulates RNA polymerase II activity during the transcription cycle.
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DOI：
10.1101/gad.1592807
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发表时间：
2007-11
影响因子：
10.5
通讯作者：
Yu-Xin Xu;J. Manley
中科院分区：
文献类型：
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作者：
Yu-Xin Xu;J. Manley
RNA聚合酶（RNAP）II最大亚基（CTD）的C末端结构域在协调前mRNA转录和加工中的多个事件中起关键作用。以前，我们报告说，肽脯氨酰异构酶Pin1调节RNAP II功能在细胞周期。在这里，我们提供的证据表明，Pin1影响RNAP II功能的多个方面，通过其调节CTD磷酸化。使用染色质免疫沉淀（ChIP）与CTD磷酸化特异性抗体的测定，我们证实，RNAP II显示在细胞周期中与特定基因的动态关联，优先与S期转录基因相关联，而在M期与CTD磷酸化变化相关的物质中解离。使用诱导型Pin1细胞系，我们表明Pin1过表达足以从染色质中释放RNAP II，然后在核斑点相关结构中以过度磷酸化的形式积累。体外转录试验表明，Pin1抑制核提取物中的转录，而一个失活的Pin1突变体，事实上刺激it.Several分析表明，抑制主要反映Pin1在转录起始期间的活动，而不是延长，这表明Pin1调制CTD磷酸化，RNAP II活性，在转录周期的早期阶段。
The C-terminal domain of the RNA polymerase (RNAP) II largest subunit (CTD) plays a critical role in coordinating multiple events in pre-mRNA transcription and processing. Previously we reported that the peptidyl prolyl isomerase Pin1 modulates RNAP II function during the cell cycle. Here we provide evidence that Pin1 affects multiple aspects of RNAP II function via its regulation of CTD phosphorylation. Using chromatin immunoprecipitation (ChIP) assays with CTD phospho-specific antibodies, we confirm that RNAP II displays a dynamic association with specific genes during the cell cycle, preferentially associating with transcribed genes in S phase, while disassociating in M phase in a matter that correlates with changes in CTD phosphorylation. Using inducible Pin1 cell lines, we show that Pin1 overexpression is sufficient to release RNAP II from chromatin, which then accumulates in a hyperphosphorylated form in nuclear speckle-associated structures. In vitro transcription assays show that Pin1 inhibits transcription in nuclear extract, while an inactive Pin1 mutant in fact stimulates it. Several assays indicate that the inhibition largely reflects Pin1 activity during transcription initiation and not elongation, suggesting that Pin1 modulates CTD phosphorylation, and RNAP II activity, during an early stage of the transcription cycle.