生物谷报道：最近，中科院上海生命科学研究院神经研究所袁小兵研究组的陈罡、司马健和金明等的研究首次证明了一种梯度表达的分泌性导向分子Semaphorin-3A指引了皮层神经元的放射状迁移。采用在体子宫内基因电转技术，他们可长时程观察一群皮层神经元在体内的迁移。发现体内通过阻断Semaphorin-3A的信号可以导致迁移的停滞并伴随神经元伸展方向的错乱。1月10日，Nature Neuroscience发表了该成果。
体外实验也发现内源性Semaphorin-3A的浓度梯度对于新生神经元的正确迁移是必须的，并且起吸引性导向作用。这些研究首次证明了神经元的放射状迁移受胞外导向分子的指引。这种迁移的趋化性导向假说有助于我们更好的理解高度有序的皮层结构是如何形成的。
该项研究工作得到了中国科学院、“973”计划、重要科学研究计划、国家自然科学基金委员会杰出青年基金及上海市启明星计划的资助。（援引上海生命科学研究院）
生物谷推荐原始出处：
Nature Neuroscience 11, 36 - 44 (2007)
Published online: 2 December 2007 | Corrected online: 9 December 2007 | doi:10.1038/nn2018
Semaphorin-3A guides radial migration of cortical neurons during development
Gang Chen1,2,3, Jian Sima1,2,3, Ming Jin1,3, Kai-yu Wang1,2, Xiao-jing Xue1,2, Wang Zheng1,2, Yu-qiang Ding1 & Xiao-bing Yuan1
Abstract
Postmitotic neurons in the developing cortex migrate along radial glial fibers to their proper location in the cortical plate and form the layered structure. Here we report that the radial migration of rat layer II/III cortical neurons requires guidance by the extracellular diffusible factor Semaphorin-3A (Sema3A). This factor is expressed in a descending gradient across the cortical layers, whereas its receptor neuropilin-1 (NP1) is highly expressed in migrating neurons. Downregulation or conditional knockout of NP1 in newborn cortical neurons impedes their radial migration by disrupting their radial orientation during migration without altering their cell fate. Studies in cultured cortical slices further show that the endogenous gradient of Sema3A is required for the proper migration of newborn neurons. In addition, transwell chemotaxis assays show that isolated newborn neurons are attracted by Sema3A. Thus, Sema3A may function as a chemoattractive guidance signal for the radial migration of newborn cortical neurons toward upper layers.
Institute of Neuroscience and Key State Laboratory of Neurobiology, Shanghai Institute for Biological Sciences, 320 Yue Yang Road, Shanghai 200031, China.
Graduate School of the Chinese Academy of Sciences, Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, China.
These authors contributed equally to this work.
Correspondence to: Xiao-bing Yuan1 e-mail: yuanxb@ion.ac.cn
* In the version of the supplementary information originally published online for this manuscript, the legends for Supplementary Video #3 and Supplementary Video #4 were inadvertently switched. This error has now been corrected and the legends correctly describe the appropriate videos
