Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany.
Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany.
Dev Cell. 2015 Jan 26;32(2):203-19. doi: 10.1016/j.devcel.2014.12.001. Epub 2015 Jan 15.
Pseudostratified epithelia are widespread during animal development and feature elongated cells whose nuclei adopt various positions along the apicobasal cell axis. Before mitosis, nuclei migrate toward the apical surface, and subsequent divisions occur apically. So far, the exact purpose of this nuclear migration remained elusive. One hypothesis was that apical migration ensures that nuclei and centrosomes meet for mitosis. We here demonstrate that in zebrafish neuroepithelia apical nuclear migration occurs independently of centrosome position or integrity. It is a highly reproducible phenomenon linked to the cell cycle via CDK1 activity. We propose that the robustness of bringing nuclei apically for mitosis ensures that cells are capable of reintegrating into the epithelium after division. Nonapical divisions lead to cell delamination and formation of cell clusters that subsequently interfere with neuronal layering. Therefore, positioning divisions apically in pseudostratified neuroepithelia could serve to safeguard epithelial integrity and enable proper proliferation and maturation.
假复层上皮在动物发育过程中广泛存在，其特征为细胞细长，细胞核沿细胞的顶底轴呈现出各种位置。在有丝分裂之前，细胞核向顶端表面迁移，随后的分裂发生在顶端。到目前为止，这种核迁移的确切目的还不清楚。有一种假设是，顶端迁移确保了细胞核和中心体在有丝分裂时相遇。我们在这里证明，在斑马鱼神经上皮中，顶端核迁移的发生与中心体的位置或完整性无关。这是一个高度可重复的现象，通过 CDK1 活性与细胞周期相关联。我们提出，将细胞核带到顶端进行有丝分裂的稳健性确保了细胞在分裂后能够重新整合到上皮中。非顶端分裂导致细胞分层和细胞簇的形成，随后干扰神经元的分层。因此，在假复层神经上皮中，将有丝分裂定位在顶端可以起到保护上皮完整性的作用，并使增殖和成熟正常进行。
