Departments of Systems Biology and Biochemistry and Molecular Biophysics, Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA; Departments of Pathology and Cell Biology, Neurology, and Neuroscience, Center for Motor Neuron Biology and Disease, Columbia Stem Cell Initiative, Columbia University, New York, NY 10032, USA.
Departments of Systems Biology and Biochemistry and Molecular Biophysics, Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA.
Neuron. 2018 Feb 21;97(4):853-868.e6. doi: 10.1016/j.neuron.2018.01.020. Epub 2018 Feb 1.
Neuronal maturation requires dramatic morphological and functional changes, but the molecular mechanisms governing this process are not well understood. Here, we studied the role of Rbfox1, Rbfox2, and Rbfox3 proteins, a family of tissue-specific splicing regulators mutated in multiple neurodevelopmental disorders. We generated Rbfox triple knockout (tKO) ventral spinal neurons to define a comprehensive network of alternative exons under Rbfox regulation and to investigate their functional importance in the developing neurons. Rbfox tKO neurons exhibit defects in alternative splicing of many cytoskeletal, membrane, and synaptic proteins, and display immature electrophysiological activity. The axon initial segment (AIS), a subcellular structure important for action potential initiation, is diminished upon Rbfox depletion. We identified an Rbfox-regulated splicing switch in ankyrin G, the AIS "interaction hub" protein, that regulates ankyrin G-beta spectrin affinity and AIS assembly. Our data show that the Rbfox-regulated splicing program plays a crucial role in structural and functional maturation of postmitotic neurons.
神经元成熟需要显著的形态和功能变化，但调控这一过程的分子机制尚不清楚。在这里，我们研究了 Rbfox1、Rbfox2 和 Rbfox3 蛋白的作用，它们是一组组织特异性剪接调控因子，在多种神经发育障碍中发生突变。我们生成了 Rbfox 三重敲除（tKO）腹侧脊髓神经元，以确定 Rbfox 调控下的替代外显子的综合网络，并研究它们在发育神经元中的功能重要性。Rbfox tKO 神经元表现出许多细胞骨架、膜和突触蛋白的剪接缺陷，并表现出不成熟的电生理活性。轴突起始段（AIS）是一种对于动作电位起始很重要的亚细胞结构，在 Rbfox 耗竭时会减少。我们在 ankyrin G 中鉴定出一个 Rbfox 调控的剪接开关，ankyrin G 是 AIS 的“相互作用枢纽”蛋白，调节 ankyrin G-β spectrin 的亲和力和 AIS 的组装。我们的数据表明，Rbfox 调控的剪接程序在有丝分裂后神经元的结构和功能成熟中起着关键作用。
