Hepker J, Wang Q T, Motzny C K, Holmgren R, Orenic T V
Department of Biochemistry, Northwestern University, Evanston, IL 60208, USA.
Development. 1997 Jan;124(2):549-58. doi: 10.1242/dev.124.2.549.
The Drosophila segment polarity gene cubitus interruptus (ci) encodes a zinc finger protein that is required for the proper patterning of segments and imaginal discs. Epistasis analysis indicates that ci functions in the Hedgehog (Hh) signal transduction pathway and is required to maintain wingless expression in the embryo. In this paper, the role of the Ci protein in the Hh signaling pathway is examined in more detail. Our results show that ectopic expression of ci in imaginal discs and the embryo activates the expression of Hh target genes. One of these target genes, patched, forms a negative feedback loop with ci that is regulated by Hh signal transduction. Activation is also achieved using the Ci zinc finger domain fused to a heterologous transactivation domain. Conversely, repression of Hh target genes occurs in animals expressing the Ci zinc finger domain fused to a repression domain. To examine Ci function in more detail, regions of the Ci protein that are responsible for its ability to transactivate and its subcellular distribution have been identified.
果蝇体节极性基因间断翅脉（ci）编码一种锌指蛋白，该蛋白是体节和成虫盘正确模式形成所必需的。上位性分析表明，ci在刺猬信号（Hh）转导途径中起作用，并且是维持胚胎中无翅基因表达所必需的。在本文中，我们更详细地研究了Ci蛋白在Hh信号通路中的作用。我们的结果表明，ci在成虫盘和胚胎中的异位表达激活了Hh靶基因的表达。这些靶基因之一，patched基因与ci形成了一个由Hh信号转导调节的负反馈环。使用与异源反式激活结构域融合的Ci锌指结构域也能实现激活。相反，在表达与抑制结构域融合的Ci锌指结构域的动物中，Hh靶基因受到抑制。为了更详细地研究Ci的功能，已经确定了Ci蛋白中负责其反式激活能力及其亚细胞分布的区域。
