PDF(Pubmed)
Abstract：
During neural development, sculpting of early formed circuits by cell death and synaptic pruning is necessary to generate a functional and efficient nervous system. This allows for the establishment of rudimentary circuits which necessitate early organism survival to later undergo subsequent refinement. These changes facilitate additional specificity to stimuli which can lead to increased behavioral complexity. In multiple species, Rohon-Beard neurons (RBs) are the earliest mechanosensory neurons specified and are critical in establishing a rudimentary motor response circuit. Sensory input from RBs gradually becomes redundant as dorsal root ganglion (DRG) neurons develop and integrate into motor circuits. Previous studies demonstrate that RBs undergo a dramatic wave of cell death concurrent with development of the DRG. However, contrary to these studies, we show that neurogenin1+ (ngn1) RBs do not undergo a widespread wave of programmed cell death during early zebrafish development and instead persist until at least 15 days post fertilization (dpf). Starting at 2 dpf, we also observed a dramatic medialization and shrinkage of ngn1+ RB somas along with a gradual downregulation of ngn1 in RBs. This alters a fundamental premise of early zebrafish neural development and opens new avenues to explore mechanisms of RB function, persistence, and circuit refinement.
摘要：
在神经发育过程中,通过细胞死亡和突触修剪来雕刻早期形成的电路对于产生功能性和有效的神经系统是必要的。这允许建立基本的回路，这需要早期的有机体存活，以便以后进行后续的精炼。这些变化促进了对刺激的额外特异性，这可能导致行为复杂性增加。在多个物种中，Rohon-Beard神经元（RB）是最早指定的机械感觉神经元，对于建立基本的运动反应回路至关重要。随着背根神经节（DRG）神经元的发展并整合到运动电路中，来自RB的感觉输入逐渐变得多余。先前的研究表明，与DRG的发展同时，RB经历了巨大的细胞死亡浪潮。然而,与这些研究相反，我们表明，neurogenin1+（ngn1）RB在斑马鱼早期发育过程中不会经历广泛的程序性细胞死亡波，而是持续到受精后至少15天。从2dpf开始，我们还观察到ngn1+RB体的急剧中介化和收缩，以及rbs中ngn1的逐渐下调。这改变了早期斑马鱼神经发育的基本前提，为探索RB功能机制开辟了新的途径。持久性,和电路细化。
