Distinct roles for secreted semaphorin signaling in spinal motor axon guidance
Distinct roles for secreted semaphorin signaling in spinal motor axon guidance
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DOI：
10.1016/j.neuron.2005.12.003
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发表时间：
2005-12-22
期刊：
影响因子：
16.2
通讯作者：
Kolodkin, AL
中科院分区：
文献类型：
--
作者：
Huber, AB;Kania, A;Kolodkin, AL
神经纤毛蛋白，分泌的脑信号蛋白共受体，在离散的脊髓运动神经元群体中表达，这表明它们为功能性运动回路的建立提供了关键的指导信息。我们在这里表明，运动轴突的生长和指导是受损的Sema 3A-Npn-1信号的情况下。运动轴突早熟地进入肢体，表明Sema 3A控制运动轴突向肢体内生长的时间。脊神经内的外侧运动柱（LMC）运动轴突在向肢体生长并会聚在丛区域时被去束化。内侧和外侧LMC运动轴突显示背腹引导缺陷的前肢。相比之下，Sema 3F-Npn-2信号引导内侧亚组LMC神经元的轴突到腹侧肢体，但在调节其成束中没有发挥主要作用。因此，Sema 3A-Npn-1和Sema 3F-Npn-2信号传导控制脊髓运动连接形成期间运动轴突生长和引导的不同步骤。
Neuropilins, secreted semaphorin coreceptors, are expressed in discrete populations of spinal motor neurons, suggesting they provide critical guidance information for the establishment of functional motor circuitry. We show here that motor axon growth and guidance are impaired in the absence of Sema3A-Npn-1 signaling. Motor axons enter the limb precociously, showing that Sema3A controls the timing of motor axon in-growth to the limb. Lateral motor column (LMC) motor axons within spinal nerves are defasciculated as they grow toward the limb and converge in the plexus region. Medial and lateral LMC motor axons show dorso-ventral guidance defects in the forelimb. In contrast, Sema3F-Npn-2 signaling guides the axons of a medial subset of LMC neurons to the ventral limb, but plays no major role in regulating their fasciculation. Thus, Sema3A-Npn-1 and Sema3F-Npn-2 signaling control distinct steps of motor axon growth and guidance during the formation of spinal motor connections.