精神发育迟滞相关基因CDKL3对神经元轴突形态发育的影响

The Role of Non-syndromic Mild Mental Retardation Correlative Gene CDKL3 in the Development of Neuronal Dendrites

目的:探讨精神发育迟滞相关基因CDKL3在神经元轴突生长发育中的作用,从而揭示CDKL3失活与精神发育迟滞间的内在联系。方法:采用逆转录-聚合酶链反应(RT-PCR)和逆转录-实时定量聚合酶链反应(RT-realtimequantitivePCR)方法研究内源性CDKL3基因在小鼠中枢神经系统发育中mRNA水平的时空表达,采用RNA干扰技术和免疫荧光组化方法研究CDKL3在小鼠体外培养神经元轴突早期发育中的作用。结果:RT-PCR和RT-realtimequantitivePCR结果显示,CDKL3在小鼠胚胎14d开始表达,出生时达峰,随后下降,出生14d时降至较低水平并维持至成年后。免疫荧光组化结果显示,用RNA干扰技术敲减体外培养神经元中的CDKL3可引起神经元轴突分支数量和总长度的显著增加,而上调神经元中的CDKL3可引起相反的结果,并且敲减CDKL3对神经元的病理影响可被转染入神经元的RNA干扰质粒相对应的CDKL3-Res质粒所拯救。结论:CDLK3的表达和活动在神经元轴突的生长、分支形成中具有至关重要的作用,CDKL3失活引起神经元轴突形态发育异常可能与非综合征轻型精神发育迟滞的特征表现相关。

Aim： To investigate the role of CDKL3 in the development of neuronal axons and further reveal the underline relationship between CDKL3 inactivation and the non-syndromic mild mental retardation. Methods： CDKL3 distribution and expression in the mouse developing nervous system were investigated by RT-PCR and realtime quantitive PCR. The role of CDKL3 in the development of neuronal axons in vitro were investigated by RNAi and immunofluorescence. Results： The results of RT-PCR and realtime quantitive PCR showed that CDKL3 was first detected at E14, peaked at birth, and then declined slightly. It maintained at low levels from P14 to adulthood. Depleting CDKL3 promoted axon growth and branching, while CDKL3 upregulation had the opposite effect on axon branching without affecting total axon length,and co-expressing CDKL3-Res prevented the shRNA-#2-mediated defects. Conclusion： CDKL3 takes a critical role in the development of neuronal axon. Furthermore, CDKL3 inactivation may contribute to non-syndromic mild mental retardation by affecting axon morphogenesis during crucial stages of their formation.