Interplay between E-box and NF-κB in regulation of A20 gene by DRB sensitivity-inducing factor (DSIF)
Interplay between E-box and NF-κB in regulation of A20 gene by DRB sensitivity-inducing factor (DSIF)
复制标题
DOI：
10.1074/jbc.m706767200
复制
发表时间：
2008-01-18
影响因子：
4.8
通讯作者：
Dikstein, Rivka
中科院分区：
文献类型：
--
作者：
Amir-Zilberstein, Liat;Dikstein, Rivka
NF-κ B靶基因A20作为转录延伸的基因特异性控制的范例。该基因由延伸因子DSIF（DRB敏感性诱导因子）在基础状态和NF-κ B激活状态下通过两种不同的机制调节。在NF-κ B刺激之前，A20基因被聚合酶II占据，并且延伸被DSIF抑制。这种抑制是由上游启动子元件称为ELIE（延伸抑制元件）介导的。在NF-κ B激活后，DSIF对A20基因的抑制持续存在，但现在NF-κ B和核心启动子调节DSIF而不是ELIE。我们研究了ELIE对DSIF的调节以及NF-κ B诱导后从ELIE到NF-κ B的调节转换。电泳迁移率变动分析揭示了两种不同的蛋白质复合物，特异性地与ELIE相互作用，其中之一是E-box蛋白USF 1。有趣的是，在NF-κ B诱导后，USF 1从A20启动子置换。ELIE的E-box部分的突变减少了USF 1和DSIF募集的结合。与这些发现相一致，E盒对于静息细胞中的DSIF抑制是至关重要的，但对于NF-κ B刺激的细胞则不是。这些发现揭示了DSIF的动态调节，涉及E-box或NF-κ B，这取决于生理环境。
The NF-kappa B target gene A20 serves as a paradigm for gene-specific control of transcription elongation. This gene is regulated by the elongation factor DSIF (DRB sensitivity-inducing factor) under basal and NF-kappa B-activated states by two distinct mechanisms. Prior to NF-kappa B stimulation, the A20 gene is occupied by polymerase II, and elongation is inhibited by DSIF. This inhibition is mediated by an upstream promoter element termed ELIE (elongation inhibitory element). Upon NF-kappa B activation, inhibition of the A20 gene by DSIF persists, but now NF-kappa B and the core promoter regulate DSIF instead of ELIE. Here we investigated the regulation of DSIF by ELIE and the regulatory switch from ELIE to NF-kappa B following NF-kappa B induction. Electrophoretic mobility shift assays revealed two distinct protein complexes that specifically interact with ELIE, one of which is the E-box protein USF1. Interestingly, USF1 is displaced from the A20 promoter upon induction of NF-kappa B. A mutation in the E-box section of ELIE diminished the binding of USF1 and DSIF recruitment. Consistent with these findings, the E-box is crucial for DSIF inhibition in resting, but not NF-kappa B stimulated, cells. These findings reveal a dynamic regulation of DSIF involving either E-box or NF-kappa B depending on the physiological circumstances.