Identification and differential expression of multiple isoforms of mouse Coiled-coil-DIX1 (Ccd1), a positive regulator of Wnt signaling
Identification and differential expression of multiple isoforms of mouse Coiled-coil-DIX1 (Ccd1), a positive regulator of Wnt signaling
复制标题
DOI：
10.1016/j.molbrainres.2004.12.002
复制
发表时间：
2005-04-27
期刊：
影响因子：
--
通讯作者：
Masu, M
中科院分区：
文献类型：
--
作者：
Shiomi, K;Kanemoto, M;Masu, M
Wnt 信号传导在细胞生长、分化、极性形成和神经发育中发挥重要作用。在规范途径中，含有两个DIX结构域； Disheveled (Dvl) 和 Axin 蛋白调节 β-连环蛋白的降解，从而通过 TCF/LEF 家族转录因子激活 Wnt 靶基因。最近，我们分离出了第三种具有 DIX 结构域的蛋白，Coiled-coil-DIX1 (Ccd1)。 Ccd1 与 DO 和 Axin 形成同聚和异聚复合物，并通过 Writ 通路激活调节斑马鱼胚胎中的神经模式。在这里，我们报告了小鼠 Ccd1 的分离和表征。通过不同的启动子使用和选择性剪接产生了 14 种假定的 mRNA 亚型，每种亚型在不同组织中显示出不同的表达模式。预测的 Ccd1 蛋白分为三种亚型，一种称为 CCd1A 的新形式具有 N 末端钙调蛋白同源结构域，表明该亚型与肌动蛋白或其他蛋白存在额外的相互作用。当 Ccd1 蛋白在 Hela 细胞中单独表达时，它们自身几乎没有表现出 TCF 依赖性报告基因转录的激活。然而，当 Dvl 蛋白在自身不激活 Writ 途径的水平与 Ccd1 共表达时，报告基因转录以 Ccd1 剂量依赖性方式大大增强。此外，Writ 通路的 Ccd1 和 Wnt3a 依赖性激活被 Axin 或显性失活 Ccd1 抑制。这些结果表明小鼠 Ccd1 作为 Wnt/β-连环蛋白途径的正调节因子发挥作用。此外，Ccd1 在胚胎和成人大脑中高度表达并与 Wnt 信号分子共定位，这表明 Ccd1 在 Wnt 介导的神经元发育、可塑性和重塑中的重要性。 (c) 2004 Elsevier B.V 保留所有权利。
The Wnt signaling plays important roles in cell growth, differentiation, polarity formation, and neural development. In the canonical pathway, two DIX domain-containing; proteins, Dishevelled (Dvl) and Axin, regulate the degradation of beta-catenin that activates Wnt target genes through TCF/LEF family transcription factors. Recently, we have isolated a third type of DIX domain-possessing protein, Coiled-coil-DIX1 (Ccd1). Ccd1 forms homomeric and heteromeric complexes with DO and Axin, and regulates the neural patterning in zebrafish embryos through Writ pathway activation. Here, we report the isolation and characterization of mouse Ccd1. Fourteen putative mRNA isoforms are generated by different promoter usage and alternative splicing, and each isoform shows different expression patterns in various tissues. The predicted Ccd1 proteins are classified into three subtypes, and a novel form, termed CCd1A, possesses an N-terminal calponin homology domain, suggesting an additional interaction of the isoform with actin or other proteins. When Ccd1 proteins were singularly expressed in Hela cells, they showed almost no activation of TCF-dependent reporter transcription on their own. However, when Dvl protein, at the level that did not activate Writ pathway by itself, was co-expressed with Ccd1, the reporter transcription was greatly potentiated in Ccd1-dose-dependent manner. In addition, Ccd1- and Wnt3a-dependent activation of Writ pathway was inhibited by Axin or a dominant negative Ccd1. These results indicate that mouse Ccd1 functions as a positive regulator of the Wnt/beta-catenin pathway. Furthermore, Ccd1 is highly expressed and co-localized with Wnt signaling molecules in the embryonic and adult brain, implicating the importance of Ccd1 in the Wnt-mediated neuronal development, plasticity, and remodeling. (c) 2004 Elsevier B.V All rights reserved.