1Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
2University of the Chinese Academy of Sciences, Beijing 100049, China
3Department of Applied Mathematics, University of Washington, Seattle, Washington 98195, USA

Abstract 

A salient feature of neurons is their intrinsic ability to grow and extend neurites, even in the absence of external cues. Compared to the later stages of neuronal development, such as neuronal polarization and dendrite morphogenesis, the early steps of neuritogenesis remain relatively unexplored. Here we showed that redistribution of cortical actin into large aggregates preceded neuritogenesis and determined the site of neurite initiation. Enhancing actin polymerization by jasplakinolide treatment effectively blocked actin redistribution and neurite initiation, while treatment with the actin depolymerizing agents latrunculin A or cytochalasin D accelerated neurite formation. Together, these results demonstrate a critical role of actin dynamics and reorganization in neurite initiation. Further experiments showed that microtubule dynamics and protein synthesis are not required for neurite initiation, but are required for later neurite stabilization. The redistribution of actin during early neuronal development was also observed in the cerebral cortex and hippocampus in vivo.

Keywords

Neurite initiation Neuritogenesis Actin aggregations Actin Microtubules

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