The Tbx20 homolog Midline represses wingless in conjunction with Groucho during the maintenance of segment polarity
The Tbx20 homolog Midline represses wingless in conjunction with Groucho during the maintenance of segment polarity
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DOI：
10.1016/j.ydbio.2012.07.004
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发表时间：
2012-09-15
影响因子：
2.7
通讯作者：
Brook, William J.
中科院分区：
文献类型：
--
作者：
Formaz-Preston, Ann;Ryu, Jae-Ryeon;Brook, William J.
果蝇外胚层中的无翅体节极性基因的调控对果蝇外胚层的正确形成至关重要。我们以前已经表明，不对称激活的无翼下游的Hedghog信号依赖于T-box转录因子，中线和H15。Hedgehog激活Hedgehog结构域前面的无翅，中线/H15部分负责抑制Hedgehog表达细胞后面的细胞中的无翅。在这里，我们表明，中线结合格劳乔共阻遏物直接通过enrailed同源性-1域，并需要一个完整的enrailed同源性-1域抑制无翅。相反，调节锯齿，中线抑制的第二个目标，是不依赖于enrailed-homology-1结构域。此外，我们确定了一个中线响应区的无翼顺式调控区，并显示中线结合到该区域内的序列。在转基因报告构建体中突变这些序列导致在中线表达结构域中的异位报告表达，这与无翅是中线阻遏的直接靶标一致。(C)2012 Elsevier Inc. All rights reserved.
The regulation of the segment polarity gene wingless is essential for the correct patterning of the Drosophila ectoderm. We have previously shown that the asymmetric activation of wingless downstream of Hedghog-signaling depends on the T-box transcription factors, midline and H15. Hedgehog activates wingless anterior to the Hedgehog domain, midline/H15 are responsible in part for repressing wingless in cells posterior to the Hedgehog expressing cells. Here, we show that Midline binds the Groucho co-repressor directly via the engrailed homology-1 domain and requires an intact engrailed-homology-1 domain to repress wingless. In contrast, the regulation of Serrate, a second target of midline repression, is not dependent on the engrailed-homology-1 domain. Furthermore, we identify a midline responsive region of the wingless cis-regulatory region and show that Midline binds to sequences within this region. Mutating these sequences in transgenic reporter constructs results in ectopic reporter expression in the midline-expression domain, consistent with wingless being a direct target of Midline repression. (C) 2012 Elsevier Inc. All rights reserved.