Dries Ramona, Lange Annemarie, Heiny Sebastian, Berghaus Katja I, Bastmeyer Martin, Bentrop Joachim
Zoological Institute, Cell- and Neurobiology, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany.
Front Cell Dev Biol. 2021 Jan 14;8:591011. doi: 10.3389/fcell.2020.591011. eCollection 2020.
The posterior lateral line system (pLLS) of aquatic animals comprises small clustered mechanosensory organs along the side of the animal. They develop from proneuromasts, which are deposited from a migratory primordium on its way to the tip of the tail. We here show, that the Neural Cell Adhesion Molecule Ncam1b is an integral part of the pathways initiating and regulating the development of the pLLS in zebrafish. We find that morpholino-knockdowns of (i) reduce cell proliferation within the primordium, (ii) reduce the expression of Fgf target gene , (iii) severely affect proneuromast formation, and (iv) affect primordium migration. Ncam1b directly interacts with Fgf receptor Fgfr1a, and a knockdown of causes similar phenotypic changes as observed in -morphants. We conclude that Ncam1b is involved in activating proliferation by triggering the expression of . In addition, we demonstrate that Ncam1b is required for the expression of chemokine receptor Cxcr7b, which is crucial for directed primordial migration. Finally, we show that the knockdown of destabilizes proneuromasts, suggesting a further function of Ncam1b in strengthening the cohesion of proneuromast cells.
水生动物的后侧线系统（pLLS）由沿着动物身体侧面的小簇机械感觉器官组成。它们由原神经丘发育而来，原神经丘是在迁移原基向尾尖移动的过程中沉积下来的。我们在此表明，神经细胞黏附分子Ncam1b是启动和调节斑马鱼pLLS发育途径的一个组成部分。我们发现，对（i）的吗啉代敲低会（i）减少原基内的细胞增殖，（ii）降低Fgf靶基因的表达，（iii）严重影响原神经丘的形成，以及（iv）影响原基迁移。Ncam1b直接与Fgf受体Fgfr1a相互作用，对的敲低会导致与在 - 突变体中观察到的类似表型变化。我们得出结论，Ncam1b通过触发的表达参与激活增殖。此外，我们证明Ncam1b是趋化因子受体Cxcr7b表达所必需的，而Cxcr7b对于定向原基迁移至关重要。最后，我们表明对的敲低会使原神经丘不稳定，这表明Ncam1b在加强原神经丘细胞凝聚力方面还有进一步的功能。
