Oteíza Pablo, Köppen Mathias, Concha Miguel L, Heisenberg Carl-Philipp
Laboratory of Experimental Ontogeny, Program of Anatomy and Developmental Biology, Institute of Biomedical Sciences, University of Chile, Clasificador 7 - Correo 7, Santiago, Chile.
Development. 2008 Aug;135(16):2807-13. doi: 10.1242/dev.022228. Epub 2008 Jul 17.
Handedness of the vertebrate body plan critically depends on transient embryonic structures/organs that generate cilia-dependent leftward fluid flow within constrained extracellular environments. Although the function of ciliated organs in laterality determination has been extensively studied, how they are formed during embryogenesis is still poorly understood. Here we show that Kupffer's vesicle (KV), the zebrafish organ of laterality, arises from a surface epithelium previously thought to adopt exclusively extra-embryonic fates. Live multi-photon confocal imaging reveals that surface epithelial cells undergo Nodal/TGFbeta signalling-dependent ingression at the dorsal germ ring margin prior to gastrulation, to give rise to dorsal forerunner cells (DFCs), the precursors of KV. DFCs then migrate attached to the overlying surface epithelium and rearrange into rosette-like epithelial structures at the end of gastrulation. During early somitogenesis, these epithelial rosettes coalesce into a single rosette that differentiates into the KV with a ciliated lumen at its apical centre. Our results provide novel insights into the morphogenetic transformations that shape the laterality organ in zebrafish and suggest a conserved progenitor role of the surface epithelium during laterality organ formation in vertebrates.
脊椎动物身体结构的左右不对称性关键取决于在受限的细胞外环境中产生依赖纤毛的向左流体流动的瞬时胚胎结构/器官。尽管纤毛器官在左右不对称性决定中的功能已得到广泛研究，但它们在胚胎发生过程中如何形成仍知之甚少。在这里，我们表明斑马鱼的左右不对称性器官库普弗囊泡（KV）起源于先前被认为仅具有胚外命运的表面上皮。实时多光子共聚焦成像显示，在原肠胚形成之前，表面上皮细胞在背侧胚环边缘经历依赖于Nodal/TGFβ信号的内陷，从而产生KV的前体细胞背侧先驱细胞（DFC）。然后，DFC迁移并附着于上方的表面上皮，并在原肠胚形成末期重排形成玫瑰花结样上皮结构。在早期体节形成期间，这些上皮玫瑰花结合并成一个单一的玫瑰花结，在其顶端中心分化为具有纤毛腔的KV。我们的结果为塑造斑马鱼左右不对称性器官的形态发生转变提供了新的见解，并表明表面上皮在脊椎动物左右不对称性器官形成过程中具有保守的祖细胞作用。
