Yip Yee Ping, Capriotti Christine, Drill Emily, Tsai Li-Huei, Yip Joseph W
Department of Neurobiology, University of Pittsburgh, School of Medicine, Pittsburgh, Pennsylvania 15261, USA.
J Comp Neurol. 2007 Jul 10;503(2):297-307. doi: 10.1002/cne.21377.
It has been shown that cyclin-dependent kinase 5 (Cdk5) is crucial for neuronal migration and survival in the brain. However, the role of Cdk5 in neuronal migration in the spinal cord has never been investigated. The present study is the first to show that Cdk5 affects the migration of different populations of neurons in the developing spinal cord. In the absence of Cdk5, at least four neuronal populations failed to migrate to their final destinations: sympathetic and parasympathetic preganglionic neurons, as well as dorsally originating and ventrally originating (U-shaped group) diaphorase-positive dorsal horn interneurons. In contrast, the migration of somatic motor neurons and various types of ventral and dorsal interneurons was unaffected by the absence of Cdk5. Moreover, our results suggest that Cdk5-dependent migration in the developing spinal cord is axon- or glial fiber-mediated. Finally, our results show that sympathetic preganglionic neurons and somatic motor neurons in Cdk5-deficient mice continue to extend processes and project toward their normal target areas, suggesting that Cdk5 has no obvious effects on axonal outgrowth and guidance mechanisms of these two neuronal populations in spinal cord development.
研究表明，细胞周期蛋白依赖性激酶5（Cdk5）对大脑中神经元的迁移和存活至关重要。然而，Cdk5在脊髓神经元迁移中的作用从未被研究过。本研究首次表明，Cdk5影响发育中脊髓不同类型神经元的迁移。在缺乏Cdk5的情况下，至少有四类神经元未能迁移到它们的最终目的地：交感和副交感节前神经元，以及背侧起源和腹侧起源（U形组）的黄递酶阳性背角中间神经元。相比之下，躯体运动神经元以及各种类型的腹侧和背侧中间神经元的迁移不受Cdk5缺失的影响。此外，我们的结果表明，发育中脊髓中依赖Cdk5的迁移是由轴突或胶质纤维介导的。最后，我们的结果表明，Cdk5缺陷小鼠中的交感节前神经元和躯体运动神经元继续延伸突起并向其正常靶区投射，这表明Cdk5在脊髓发育中对这两类神经元的轴突生长和导向机制没有明显影响。
