Phosphorylation of ezrin on threonine T567 plays a crucial role during compaction in the mouse early embryo
Phosphorylation of ezrin on threonine T567 plays a crucial role during compaction in the mouse early embryo
复制标题
DOI：
10.1016/j.ydbio.2004.03.024
复制
发表时间：
2004-07-01
影响因子：
2.7
通讯作者：
Maro, B
中科院分区：
文献类型：
--
作者：
Dard, N;Louvet-Vallée, S;Maro, B
小鼠胚胎着床前的发育导致了前两个细胞谱系的分化，即内细胞团和滋养外胚层。在8-细胞期的致密过程中微绒毛极的形成和在有丝分裂过程中的不对称遗传是这两个细胞群出现的关键事件。Ezrim是ERM蛋白家族的成员，似乎参与了顶端微绒毛极的形成和稳定。为了进一步确定其在早期发育中的功能，我们突变了关键残基T567，据报道，T567是通过磷酸化调节Ezrin功能所必需的。在这里，我们证明了Ezrin突变体的表达，其中COOH末端的苏氨酸T567被天冬氨酸(模拟磷酸化残基；T567D)或丙氨酸(为了避免磷酸化；T567A)取代，干扰了E-钙粘蛋白的功能，并破坏了发育的第一个形态发生事件：紧致和空化。活性突变体Ezrin-T567D可诱导卵裂球表面形成大量异常长的微绒毛。此外，它分布在细胞皮质周围，并在八细胞阶段抑制细胞与细胞的黏附和细胞极化。在接下来的几个阶段中，只有一半的胚胎能够致密并最终空化。在这些胚胎中，Ezrin-T567D在基外区的数量减少，而贴壁连接的比例增加。反向失活突变体Ezrin-T567A主要是细胞质的，不干扰8-细胞期的紧致。然而，在16-细胞期，它重新定位在基底外侧皮质，导致附着连接表面的强烈减少，最终导致胚胎流产发育。我们的结果表明，Ezrin直接参与了小鼠早期胚胎微绒毛的形成。此外，他们还表明，Ezrin在基底外侧区域的维持可以防止微绒毛的破坏，并抑制正常细胞的形成。E-钙粘附素介导的接触，从而损害胚泡的极化和胚泡的形态发生。(C)2004 Elsevier Inc.保留所有权利。
The preimplantation development of the mouse embryo leads to the divergence of the first two cell lineages, the inner cell mass and the trophectoderm. The formation of a microvillus pole during compaction at the eight-cell stage and its asymmetric inheritance during mitosis are key events in the emergence of these two cell populations. Ezrim, a member of the ERM protein family, seems to be involved in the formation and stabilization of this apical microvillus pole. To further characterize its function in early development, we mutated the key residue T567, which was reported to be essential for regulation of ezrin function through phosphorylation. Here, we show that expression of ezrin mutants in which the COOH-terminal threonine T567 was replaced by an aspartate (to mimic a phosphorylated residue; T567D) or by an alanine (to avoid phosphorylation; T567A) interferes with E-cadherin function and disrupts the first morphogenetic events of development: compaction and cavitation. The active mutant ezrin-T567D induces the formation of numerous and abnormally long microvilli at the surface of blastomeres. Moreover, it localizes all around the cell cortex and inhibits cell-cell adhesion and cell polarization at the eight-cell stage. During the following stages, only half of the embryos are able to compact and finally to cavitate. In those embryos, the amount of ezrin-T567D decreases in the basolateral areas, while the proportion of adherens junctions increases. The reverse inactive mutant ezrin-T567A is mainly cytoplasmic and does not perturb compaction at the eight-cell stage. However, at the 16-cell stage, it relocalizes at the basolateral cortex, leading to a strong decrease in the surface of adherens junctions, and finally, embryos abort development. Our results show that ezrin is directly involved in the formation of microvilli in the early mouse embryo. Moreover, they indicate that maintenance of ezrin in basolateral areas prevents microvilli breakdown and inhibits the formation of normal cell-cell. contacts mediated by E-cadherin, thereby impairing blastomeres polarization and morphogenesis of the blastocyst. (C) 2004 Elsevier Inc. All rights reserved.