Induction of the reelin promoter by retinoic acid is mediated by Sp1
Induction of the reelin promoter by retinoic acid is mediated by Sp1
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DOI：
10.1111/j.1471-4159.2007.04797.x
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发表时间：
2007-10-01
影响因子：
4.7
通讯作者：
Grayson, Dennis R.
中科院分区：
文献类型：
--
作者：
Chen, Ying;Kundakovic, Marija;Grayson, Dennis R.
我们之前已经描述了人类reelin启动子的克隆，并提供了证据表明，它在一定程度上是通过甲基化的变化来调节的。我们目前的研究结果为该启动子以及转录因子Sp1和配对的盒基因6(Pax6)与其识别位点的相互作用提供了更详细的分析。该启动子在NT2细胞中进行了研究，NT2细胞是一种在体外进行分化的神经前体细胞。在用维甲酸(RA)处理这些细胞6天后，我们检测了Reelin mRNA和启动子的诱导。缺失和定点突变显示了调控所必需的功能相关序列。凝胶位移分析表明，启动子的主要作用部位位于这些转录因子可能结合的紧密排列的区域(类似于25bp)，可能形成DNA/蛋白质复合体。根据我们的结果，RA似乎可能通过与Pax6位点相邻的一个关键Sp1位点来诱导reelin的表达。我们发现，RA对Reelin启动子的诱导伴随着更高数量的Sp1和Pax6与该区域的结合。最后，我们表明，虽然Sp1位点的突变阻止了RA介导的启动子的诱导，但Pax6位点的类似突变不会。这些数据表明，虽然Pax6位点在调节reelin表达方面发挥了作用，但它并不是RA诱导所必需的。
We have previously described the cloning of the human reelin promoter and provided evidence that it is regulated, in part, through changes in methylation. Results from our current studies provide a more detailed analysis of this promoter and the interactions of the transcription factors Sp1 and paired box gene 6 (Pax6) with their recognition sites. The promoter was studied in NT2 cells which are a neuroprogenitor line that undergoes differentiation in vitro. We examined reelin mRNA and promoter induction following a 6-day treatment of these cells with retinoic acid (RA). Deletion and site-directed mutations showed functionally relevant sequences necessary for regulation. Gel-shift assays demonstrated that the main site of action of the promoter lies within a closely packed (similar to 25 bp) region in which these transcription factors likely bind, possibly forming a DNA/protein complex. Based on our results, it appears likely that RA-induces reelin expression through a critical Sp1 site that resides adjacent to the Pax6 site within this multisite enhancer region. We show that induction of the reelin promoter with RA is accompanied by higher amounts of Sp1 and Pax6 binding to this region. Finally, we show that while mutations in the Sp1 site prevent the RA-mediated promoter induction, similar mutations in the Pax6 site do not. The data suggest that while the Pax6 site plays a role in modulating reelin expression, it is not absolutely required for induction by RA.