Loss of neural recognition molecule NB-3 delays the normal projection and terminal branching of developing corticospinal tract axons in the mouse
Loss of neural recognition molecule NB-3 delays the normal projection and terminal branching of developing corticospinal tract axons in the mouse
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DOI：
10.1002/cne.22772
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发表时间：
2012-04-15
影响因子：
2.5
通讯作者：
Liu, Yaobo
中科院分区：
文献类型：
--
作者：
Huang, Zhenhui;Yu, Yang;Liu, Yaobo
神经识别分子NB-3参与神经发育和突触形成。然而，其在轴突束形成中的作用尚不清楚。在本研究中，我们发现NB-3在小鼠运动皮层深层的时间表达与皮质脊髓束（CST）的发育一致。明确的NB-3免疫反应性的CST轨迹强烈建议，NB-3的表达，特别是在投射CST轴突。通过追踪NB-3-/-小鼠不同发育阶段的CST轴突，我们发现这些轴突能够投射并形成正常的轨迹。然而，与野生型（WT）小鼠相比，NB-3-/-小鼠从胚胎到出生后阶段的投射大大延迟，这一时期与小鼠CST投射的完成一致。随后，尽管它们的投射被延迟，但NB-3-/-小鼠中的CST轴突逐渐完成正常投射。到P21阶段，NB-3-/-小鼠的CST投射特征与WT小鼠的CST投射特征无统计学差异。此外，我们还发现，在NB-3-/-小鼠中，CST轴突分支进入脊髓灰质也被延迟。与WT小鼠相比，NB-3-/-小鼠脊髓灰质中的CST神经支配面积在P30之前大大减少，并在P45时逐渐恢复正常。这些数据表明，NB-3是参与正常的投影和终端分支的发展CST轴突。J. Comp.神经元520：12271245，2012。(C)2011 Wiley Periodicals，Inc.
Neural recognition molecule NB-3 is involved in neural development and synapse formation. However, its role in axon tract formation is unclear. In this study, we found that the temporal expression of NB-3 in the deep layers of the motor cortex in mice was coincident with the development of the corticospinal tract (CST). Clear NB-3 immunoreactivity in the CST trajectory strongly suggested that NB-3 was expressed specifically in projecting CST axons. By tracing CST axons in NB-3-/- mice at different developmental stages, we found that these axons were capable of projecting and forming a normal trajectory. However, the projection was greatly delayed in NB-3-/- mice compared with wild-type (WT) mice from the embryonic to postnatal stages, a period that is coincident with the completion of the CST projection in mice. Subsequently, although their projection was delayed, CST axons in NB-3-/- mice gradually completed a normal projection. By stage P21, the characteristics of CST projections in NB-3-/- mice were not statistically different from those in WT mice. In addition, we found that the branching of CST axons into spinal gray matter also was delayed in NB-3-/- mice. The CST innervation area in the spinal gray matter of NB-3-/- mice was greatly reduced in comparison with WT mice until P30 and gradually became normal by P45. These data suggest that NB-3 is involved in the normal projection and terminal branching of developing CST axons. J. Comp. Neurol. 520:12271245, 2012. (C) 2011 Wiley Periodicals, Inc.