Transcriptional pausing caused by NELF plays a dual role in regulating immediate-early expression of the junB gene
Transcriptional pausing caused by NELF plays a dual role in regulating immediate-early expression of the junB gene
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DOI：
10.1128/mcb.02366-05
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发表时间：
2006-08-01
影响因子：
5.3
通讯作者：
Handa, Hiroshi
中科院分区：
文献类型：
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作者：
Aida, Masatoshi;Chen, Yexi;Handa, Hiroshi
体外实验中，人5，6-dichloro-1-beta-D-ribofuranosylbenzimidazole敏感性诱导因子和负性延伸因子负性调节RNA聚合酶II的转录延伸。然而，这种负性调节的生理作用还没有被很好地理解。在这里，通过使用一些方法来识别体内蛋白质-DNA的相互作用，我们证明了DSIF和NELF介导的转录暂停在调节人类JunB基因的即刻-早期表达方面具有双重功能。在IL-6诱导前，RNAPII、DsIF和NELF在JunB基因启动子近端聚集，主要集中在转录起始点+50左右。诱导后，这些蛋白继续与启动子近端结合，而RNAPII和DSIF也存在于下游区域。通过RNA干扰去除NELF的一个亚基可以提高诱导前后JunB的mRNA水平，表明DSIF和NELF介导的暂停不仅通过诱导RNAPII在诱导前暂停，而且通过抑制诱导后的转录，有助于负调控JunB的表达。这些调节机制似乎在其他即刻早期基因中也是保守的。
Human 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole sensitivity-inducing factor (DSIF) and negative elongation factor (NELF) negatively regulate transcription elongation by RNA polymerase II (RNAPII) in vitro. However, the physiological roles of this negative regulation are not well understood. Here, by using a number of approaches to identify protein-DNA interactions in vivo, we show that DSIF- and NELF-mediated transcriptional pausing has a dual function in regulating immediate-early expression of the human junB gene. Before induction by interleukin-6, RNAPII, DSIF, and NELF accumulate in the promoter-proximal region of junB, mainly at around position +50 from the transcription initiation site. After induction, the association of these proteins with the promoter-proximal region continues whereas RNAPII and DSIF are also found in the downstream regions. Depletion of a subunit of NELF by RNA interference enhances the junB mRNA level both before and after induction, indicating that DSIF- and NELF-mediated pausing contributes to the negative regulation of junB expression, not only by inducing RNAPII pausing before induction but also by attenuating transcription after induction. These regulatory mechanisms appear to be conserved in other immediate-early genes as well.