Oriented cell divisions asymmetrically segregate aPKC and generate cell fate diversity in the early Xenopus embryo
Oriented cell divisions asymmetrically segregate aPKC and generate cell fate diversity in the early Xenopus embryo
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DOI：
10.1242/dev.00490
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发表时间：
2003-06-01
期刊：
影响因子：
4.6
通讯作者：
Papalopulu, N
中科院分区：
文献类型：
--
作者：
Chalmers, AD;Strauss, B;Papalopulu, N
早期脊椎动物发育的一个关键特征是表层上皮细胞的形成，它们覆盖在非上皮深层细胞上。在非洲爪蟾中，深层和表层细胞显示出一系列差异，包括不同的初级神经发生能力。我们表明，这两个细胞群体产生的囊胚阶段的垂直定向分裂。这些发生在几次细胞分裂中，以可变的模式发生，但在胚胎之间以及从一次分裂到下一次分裂的百分比变化不大。分裂方向与细胞形状相关，表明简单的几何规则可能控制该系统中的分裂方向。我们发现，分裂细胞的分子极化，使aPKC是本地化的外部，顶端，膜。膜定位的aPKC早在单细胞阶段就可以看到，并且在囊胚分裂期间，它优先由表面细胞遗传。最后，我们表明，当64细胞阶段分离的卵裂球垂直分裂和女儿分别培养，只有继承顶膜的细胞的后代打开bHLH基因，ESR6e。我们的结论是，定向细胞分裂产生表层和深层细胞，并建立它们之间的细胞命运的多样性。
A key feature of early vertebrate development is the formation of superficial, epithelial cells that overlie nonepithelial deep cells. In Xenopus, deep and superficial cells show a range of differences, including a different competence for primary neurogenesis. We show that the two cell populations are generated during the blastula stages by perpendicularly oriented divisions. These take place during several cell divisions, in a variable pattern, but at a percentage that varies little between embryos and from one division to the next. The orientation of division correlates with cell shape suggesting that simple geometric rules may control the orientation of division in this system. We show that dividing cells are molecularly polarised such that aPKC is localised to the external, apical, membrane. Membrane localised aPKC can be seen as early as the one-cell stage and during the blastula divisions, it is preferentially inherited by superficial cells. Finally, we show that when 64-cell stage isolated blastomeres divide perpendicularly and the daughters are cultured separately, only the progeny of the cells that inherit the apical membrane turn on the bHLH gene, ESR6e. We conclude that oriented cell divisions generate the superficial and deep cells and establish cell fate diversity between them.