Impact of node ablation on the morphogenesis of the body axis and the lateral asymmetry of the mouse embryo during early organogenesis
Impact of node ablation on the morphogenesis of the body axis and the lateral asymmetry of the mouse embryo during early organogenesis
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DOI：
10.1006/dbio.1999.9276
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发表时间：
1999-07-01
影响因子：
2.7
通讯作者：
Tam, PPL
中科院分区：
文献类型：
--
作者：
Davidson, BP;Kinder, SJ;Tam, PPL
小鼠原肠胚结是脊索、底板和肠内胚层祖细胞的主要来源。该节点还可能发挥形态发生作用，因为它可以在异位移植后诱导部分身体轴。通过原肠胚形成晚期节点的消融，研究了失去这些祖细胞和形态发生活动对体轴发育的影响。在被消融的胚胎中，在早期器官发生过程中形成了明显完整的前后体轴，具有形态正常的头部褶皱、神经管和原始条纹。细胞命运分析表明，节点的丢失会引起周围胚层组织中神经外胚层和闪族中胚层的重新募集。这导致神经管和近轴中胚层的恢复。然而，胚胎的体轴被缩短，体节形成被延迟。组织学和基因表达研究表明，在大多数节点消融的胚胎中，躯干中的脊索要么缺失，要么中断，并且重建神经管腹侧区域的底板缺失。节点的丢失并不影响肠内胚层的分化或中肠和后肠的形成。在节点消融的胚胎中，侧板中胚层中Pitx2基因的表达不再局限于左侧，而是在身体两侧发现或在侧板中胚层中完全缺失。因此，节点的丢失导致无法描绘身体轴的侧向性。因此，该节点及其衍生物在早期器官发生过程中的腹侧神经管和侧向身体轴的模式中发挥着关键作用，但在前后轴的模式中则没有。 (C) 1999 年学术出版社。
The node of the mouse gastrula is the major source of the progenitor cells of the notochord, the floor plate, and the gut endoderm. The node may also play a morphogenetic role since it can induce a partial body axis following heterotopic transplantation. The impact of losing these progenitor cells and the morphogenetic activity on the development of the body axes was studied by the ablation of the node at late gastrulation. In the ablated embryo, an apparently intact anterior-posterior body axis with morphologically normal head folds, neural tube, and primitive streak developed during early organogenesis. Cell fate analysis revealed that the loss of the node elicits de novo recruitment of neural ectoderm and semitic mesoderm from the surrounding germ-layer tissues. This leads to the restoration of the neural tube and the paraxial mesoderm. However, the body axis of the embryo was foreshortened and somite formation was retarded. Histological and gene expression studies reveal that in most of the node-ablated embryos, the notochord in the trunk was either absent or interrupted, and the floor plate was absent in the ventral region of the reconstituted neural tube. The loss of the node did not affect the differentiation of the gut endoderm or the formation of the mid- and hindgut. In the node-ablated embryo, expression of the Pitx2 gene in the lateral plate mesoderm was no longer restricted to the left side but was found on both sides of the body or was completely absent from the lateral plate mesoderm. Therefore, the loss of the node results in the failure to delineate the laterality of the body axis. The node and its derivatives therefore play a critical role in the patterning of the ventral neural tube and lateral body axis but not of the anterior-posterior axis during early organogenesis. (C) 1999 Academic Press.