Rula Malgorzata E, Cai Kathy Q, Moore Robert, Yang Dong-Hua, Staub Cory M, Capo-Chichi Callinice D, Jablonski Sandra A, Howe Philip H, Smith Elizabeth R, Xu Xiang-Xi
Ovarian Cancer and Tumor Cell Biology Programs, Department of Medical Oncology, Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA.
Genesis. 2007 Jun;45(6):327-38. doi: 10.1002/dvg.20298.
The differentiation and formation of the primitive endoderm in early embryos can be mimicked in vitro by the aggregation of embryonic stem cells to form embryoid bodies. We present morphological evidence that primitive endoderm cells often first locate in the interior of embryoid bodies and subsequently migrate to the surface. Cell mixing experiments indicate that surface positioning is an intrinsic property of endoderm epithelial cells. Moreover, Disabled-2 (Dab2) is required for surface sorting and positioning of the endoderm cells: when Dab2 expression was eliminated, the differentiated endoderm epithelial cells distributed throughout the interior of the embryoid bodies. Surprisingly, E-cadherin is dispensable for primitive endoderm differentiation and surface sorting in embryoid bodies. These results support the model that primitive endoderm cells first emerge in the interior of the inner cell mass and are subsequently sorted to the surface to form the primitive endoderm.
早期胚胎中原始内胚层的分化和形成可以在体外通过胚胎干细胞聚集形成胚状体来模拟。我们提供了形态学证据，表明原始内胚层细胞通常首先位于胚状体内部，随后迁移到表面。细胞混合实验表明，表面定位是内胚层上皮细胞的固有特性。此外，Disabled-2（Dab2）是内胚层细胞表面分选和定位所必需的：当Dab2表达被消除时，分化的内胚层上皮细胞分布在胚状体的整个内部。令人惊讶的是，E-钙黏蛋白对于胚状体中原始内胚层的分化和表面分选是可有可无的。这些结果支持了这样一个模型，即原始内胚层细胞首先在内细胞团内部出现，随后被分选到表面以形成原始内胚层。
