The Differential Expression Of NeuroD In Brain During Rat Development

Objective Through investigating the changes in expression levels and location of NeuroD during neural system development of rat, to discover the NeuroD influence on neural differentiation.Methods To study the spatiotemporal expression of NeuroD during the different periods of rat brain development, the colocalization of NeuroD with NSE or GFAP was observed by immunofluorescence through confocal microscope, the expression levels of NeuroD protein were examined by Western-blotting, the expression levels of NeuroD mRNA were detected by RT-PCR.Results The result of immunofluorescence staining shown that the distribution area of NeuroD (green) was coincide with NSE (red), meanwhile, partly covered GFAP (red). NeuroD was mostly occupied in cortex, and then partly exhibited in cerebellum. NeuroD was mostly expressed near the lateral cerebral ventricle in diencephalon. The result of Western-blotting shown that NeuroD expressed in every part of brain, among these, the tiptop was in cortex, the next were in diencephalon and cerebellum. NeuroD exhibited in the different periods of brain development. The expression level of NeuroD protein increased constantly from the shape of neural tube(E9. 5) to the setup of brain form(E12. 5), and reached its head in E12.5. In the last period of embryonic development (E21. 5), brain form made the perfection, brain tissue stepped into its maturation, at the same time, NeuroD reached its head secondly. NeuroD kept itself at the same level after born. NeuroD mRNA came to exist in E7. 5. NeuroD gene andβ-actin reached their own tiptop separately from E10.5 to E12.5, and again in E21.5. The result of RT-PCR was basically met with Western-blotting. Conclusions NeuroD was expressed in the different spatio-temporal patterns during brain development. The expression level of NeuroD obviously increased in two periods, i.e., one was the early metaphase in neural development from neural tube closure(E9.5) to the primodium of prosencephalon,mesencephalon and metencephalon setup(E12.5), the other was the anaphase in neural development, when brain form made the perfection, brain tissue stepped into its maturation. NeuroD kept itself at the same level after born. Thus, it suggested the functions of NeuroD: 1,it influenced the generation and differentiation of nerve cells; 2,it played its role in the shape of synapse in the maturation of nervous system; 3,NeuroD obviously expressed near the lateral cerebral ventricle in diencephalon, which revealed that NeuroD might have the relationship with the neural stem cells migration under ependyma, still to be proved.