Effects of N-cadherin on neuronal migration during chicken optic tectum development.

N-cadherin, a member of the cadherin family, plays an important role in neural development. In addition, N-cadherin has been reported to be crucial in neuronal migration, axonal outgrowth, and axonal path-finding. However, the mechanism underlying the effects of N-cadherin in neuronal migration is not entirely clear. In this study, we investigated the overexpression or knockdown of N-cadherin in the optic tectum during chicken embryo development, and then analyzed the effect of N-cadherin on neuronal migration. The results showed that compared with the control group, in the N-cadherin knockdown group, the neuronal migration of the optic tectum was significantly affected and could not arrive at destination. The stratum griseum central layer of the optic tectum mainly includes multipolar neurons, which could not be formed after the knockdown of N-cadherin, and more neurons form the bipolar or monopolar neurons compared with the control group. Compared with the control group, more cells stayed in the neuroepithelium layer. The axonal length in the optic tectum was significantly (P < 0.001) shorter in the N-cadherin knockdown group than in the control group. These results reveal that the knockdown of N-cadherin mainly affects the length of axons and formation of multipolar neurons in the development of the chicken optic tectum, which eventually results in the inhibition of neuronal migration.