Wada Shuichi, Hamada Mayuko, Kobayashi Kenji, Satoh Nori
CREST (Core Research for Evolutional Science and Technology), Japan Science Technology Agency, Kawaguchi, Saitama 333-0012, Japan.
Dev Growth Differ. 2008 May;50(4):215-27. doi: 10.1111/j.1440-169X.2008.01012.x. Epub 2008 Mar 10.
We report here characterization of five genes for novel components of the canonical Wnt/beta-catenin signaling pathway. These genes were identified in the ascidian Ciona intestinalis through a loss-of-function screening for genes required for embryogenesis with morpholinos, and four of them have counterparts in vertebrates. The five genes we studied are as follows: Ci-PGAP1, a Ciona orthologue of human PGAP1, which encodes GPI (glycosylphosphatidylinositol) inositol-deacylase, Ci-ZF278, a gene encoding a C2H2 zinc-finger protein, Ci-C10orf11, a Ciona orthologue of human C10orf11 that encodes a protein with leucine-rich repeats, Ci-Spatial/C4orf17, a single counterpart for two human genes Spatial and C4orf17, and Ci-FLJ10634, a Ciona orthologue of human FLJ10634 that encodes a member of the J-protein family. Knockdown of each of the genes mimicked beta-catenin knockdown and resulted in suppression of the expression of beta-catenin downstream genes (Ci-FoxD, Ci-Lhx3, Ci-Otx and Ci-Fgf9/16/20) and subsequent endoderm formation. For every gene, defects in knockdown embryos were rescued by overexpression of a constitutively active form, but not wild-type, of Ci-beta-catenin. Dosage-sensitive interactions were found between Ci-beta-catenin and each of the genes. These results suggest that these five genes act upstream of or parallel to Ci-beta-catenin in the Wnt/beta-catenin signaling pathway in early Ciona embryos.
我们在此报告了经典Wnt/β-连环蛋白信号通路新组分的五个基因的特征。这些基因是通过使用吗啉代寡核苷酸对胚胎发育所需基因进行功能缺失筛选，在海鞘文昌鱼中鉴定出来的，其中四个在脊椎动物中有对应物。我们研究的五个基因如下：Ci-PGAP1，人类PGAP1的文昌鱼同源物，其编码糖基磷脂酰肌醇（GPI）肌醇脱酰酶；Ci-ZF278，一个编码C2H2锌指蛋白的基因；Ci-C10orf11，人类C10orf11的文昌鱼同源物，其编码具有富含亮氨酸重复序列的蛋白质；Ci-Spatial/C4orf17，两个人类基因Spatial和C4orf17的单一对应物；以及Ci-FLJ10634，人类FLJ10634的文昌鱼同源物，其编码J蛋白家族的一个成员。敲低每个基因都会模拟β-连环蛋白敲低，并导致β-连环蛋白下游基因（Ci-FoxD、Ci-Lhx3、Ci-Otx和Ci-Fgf9/16/20）的表达受到抑制，随后内胚层形成受阻。对于每个基因，敲低胚胎中的缺陷可通过组成型活性形式而非野生型的Ci-β-连环蛋白的过表达来挽救。在Ci-β-连环蛋白与每个基因之间发现了剂量敏感相互作用。这些结果表明，这五个基因在早期文昌鱼胚胎的Wnt/β-连环蛋白信号通路中作用于Ci-β-连环蛋白的上游或与之平行。
