ABSTRACT
Objective To construct a eukaryotic vector of chicken-derived Wnt3a tagged with EGFP (pCAG-MCs-Wnt3a-EGFP) and investigate the influence to the proliferation and axonal formation of neural precursor cells when Wnt3a was overexpressed during the development of chick embryonic spinal cord. Methods Wnt3a gene was amplified from the total RNA obtained from chick embryonic spinal cord using molecular techniques, then connected with pCAG-MCs-EGFP to construct pCAG-MCs-Wnt3a-EGFP, which was identified by digestion and genetic sequencing. At embryonic day (E) 2.5-3.0, pCAG-MCs-Wnt3a-EGFP (experimental group) and pCAG-MCs-EGFP (control group) were transfected into the chick embryonic spinal cord using in vivo electroporation, respectively. Samples were collected at E4 (5 simples of each groups) and then conducted frozen section. The immunofluorescent staining was performed to detect the expression of Wnt3a and proliferating cell nuclear actigen (PCNA) for analyzing the relationship between Wnt3a and cell proliferation, and observe the axonal formation of neural precursor according to the green fluorescence of Wnt3a protein. Results pCAG-MCs-Wnt3a-EGFP was obtained and its gene sequencing was identical with the Gene bank. Green fluorescence was observed at E4 after pCAG-MCs-Wnt3a-EGFP transformed to chick spinal cord. In transversal section of chick embryonic spinal cord, the results of immunofluorescent staining showed Wnt3a was successfully overexpressed. Meanwhile, the amount of neurons projecting axons was dramatically decreased (n=3, P < 0.01), compared to the control group, concomitant with the significant elevation of PCNA level (n =3, P < 0.01). Conclusion pCAG-MCs-Wnt3a-EGFP is successfully constructed and our study confirmed that Wnt3a plays a vital role in the proliferation and axonal formation of neural precursor cells in the developing chick spinal cord.