Gene replacement reveals a specific role for E-cadherin in the formation of a functional trophectoderm
Gene replacement reveals a specific role for E-cadherin in the formation of a functional trophectoderm
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DOI：
10.1242/dev.02722
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发表时间：
2007-01-01
期刊：
影响因子：
4.6
通讯作者：
Kemler, Rolf
中科院分区：
文献类型：
--
作者：
Kan, Natalia G.;Stemmler, Marc P.;Kemler, Rolf
在哺乳动物胚胎发生过程中，滋养外胚层是形成的第一个上皮结构。细胞粘附分子E-cadherin对于从致密桑椹胚到胚泡形成的过渡是最终必需的，以确保在滋养外胚层中正确建立粘附连接。在这里，我们分析了在何种程度上E-cadherin赋予独特的粘附和信号转导特性的滋养外胚层形成在体内。使用基因置换的方法，我们引入了N-钙粘蛋白的cDNA到E-钙粘蛋白基因组位点。我们发现，从E-钙粘蛋白基因座驱动的N-钙粘蛋白的表达反映了内源性E-钙粘蛋白的表达模式。共表达E-和N-钙粘蛋白的杂合子小鼠是至关重要的，并显示正常的胚胎发育。有趣的是，N-钙粘蛋白纯合突变胚胎表型复制E-钙粘蛋白缺失突变胚胎。去除母体E-钙粘蛋白后，我们证明N-钙粘蛋白能够提供足够的细胞粘附来介导桑椹胚压实，但不足以随后形成完全极化的功能性滋养外胚层。当ES细胞从N-钙粘蛋白纯合突变胚胎和畸胎瘤中分离出来时，这些ES细胞分化成各种各样的组织样结构。重要的是，形成了表达N-钙粘蛋白的不同上皮样结构，包括呼吸道上皮、具有角化迹象的鳞状上皮和具有杯状细胞的分泌上皮。因此，N-钙粘蛋白可以维持上皮细胞在分化的ES细胞，但不是在滋养外胚层的形成。我们的研究结果指出了E-钙粘蛋白在小鼠着床前发育过程中的特异性和独特的功能。
During mammalian embryogenesis the trophectoderm represents the first epithelial structure formed. The cell adhesion molecule E-cadherin is ultimately necessary for the transition from compacted morula to the formation of the blastocyst to ensure correct establishment of adhesion junctions in the trophectoderm. Here, we analyzed to what extent E-cadherin confers unique adhesion and signaling properties in trophectoderm formation in vivo. Using a gene replacement approach, we introduced N-cadherin cDNA into the E-cadherin genomic locus. We show that the expression of N-cadherin driven from the E-cadherin locus reflects the expression pattern of endogenous E-cadherin. Heterozygous mice co-expressing E- and N-cadherin are vital and show normal embryonic development. Interestingly, N-cadherin homozygous mutant embryos phenocopy E- cadherin-null mutant embryos. Upon removal of the maternal E- cadherin, we demonstrate that N-cadherin is able to provide sufficient cellular adhesion to mediate morula compaction, but is insufficient for the subsequent formation of a fully polarized functional trophectoderm. When ES cells were isolated from N-cadherin homozygous mutant embryos and teratomas were produced, these ES cells differentiated into a large variety of tissue-like structures. Importantly, different epithelial-like structures expressing N-cadherin were formed, including respiratory epithelia, squamous epithelia with signs of keratinization and secretory epithelia with goblet cells. Thus, N-cadherin can maintain epithelia in differentiating ES cells, but not during the formation of the trophectoderm. Our results point to a specific and unique function for E- cadherin during mouse preimplantation development.