Mechanistic analyses of transcriptional regulation via RNA-binding proteins

一种新的协同激活子hnRNP R（异质核核糖核蛋白R）在体外与Mediator合作促进c-fos启动子的转录重启动。由CDK8、Cyclin C、MED12和MED13组成的CDK8模块减少了hnRNP R和Mediator的协同作用。hnRNP与支架组分（Mediator， TBP和TFIIH）以及TFIIB相互作用，将Pol II和TFIIF招募到支架中。无g盒产生的RNA转录物通过RNA识别基序（RRMs）和精氨酸-甘氨酸-甘氨酸（RGG）结构域与hnRNP R相互作用。小鼠细胞中hnRNP R的敲低损害了几个直接早期基因的快速诱导。这些结果表明hnRNP在调节即时早期基因的强烈反应中起着重要作用。

A novel coactivator hnRNP R (heterogeneous nuclear ribonucleoprotein R) facilitates transcription reinitiation from the c-fos promoter in vitro in cooperation with Mediator. The cooperative action of hnRNP R and Mediator is diminished by the CDK8 module, which is comprised of CDK8, Cyclin C, MED12, and MED13 of the Mediator subunits. Consistently, hnRNP R interacts with the Scaffold components (Mediator, TBP, and TFIIH) as well as TFIIB, which recruits Pol II and TFIIF to Scaffold. The RNA transcript produced from the G-free cassette interacts with hnRNP R through its RNA recognition motifs (RRMs) and arginine-glycine-glycine (RGG) domain. Knockdown of hnRNP R in mouse cells compromised rapid induction of several immediate-early genes. These results suggest an important role for hnRNP R in regulating robust response of immediate-early genes.