小鼠脊髓发育候选基因Wnt7b的初步研究

目的:探讨Wnt7b基因及Wnt信号系统分子对小鼠脊髓发育的作用。方法:基因测序比较A/J和C57BL/6J两种小鼠Wnt7b基因开放阅读框架序列差异;以RT-PCR方法测定Wnt7b基因在两种小鼠组织中的表达差异;免疫组化法测定Frizzled在2种孕14天胎鼠脊髓上的表达和分布。结果:测序结果中发现两种小鼠Wnt7b开放阅读框架序列结构具有差异;在2种小鼠8种组织中,脊髓、肌肉、脾和肾中的Wnt7b基因表达具有明显差异;免疫组化的测定表明,发育14天的胎鼠脊髓上的Frizzled表达强度和分布范围具有显著差异,尤其是A/J小鼠在神经管周围表达明显强于C57BL/6J。结论:基因表达差异和基因结构差异提示,Wnt7b基因与脊髓发育具有一定的关联,应为一脊髓发育候选基因;Frizzled的强表达与脊髓发育的抑制相关,Wnt7b的信号转导途径介导了控制脊髓发育的过程。

Preliminary studies on Wnt7b: A Candidate Gene Controlling Development of Spinal Cord in Mice

Objective: To determine the role that Wnt7b gene and Wnt signaling pathway play during the mouse spinal cord development. Methods: Firstly, the amplified products for ORF region of Wnt7b gene of the two strain mice A/J and C57BL/6J were sequenced to compare their differences. Secondly, the difference in the expression of Wnt7b gene between the tissues of the two strains was detected by RT-PCR. Thirdly, immunohistochemistry using a Frizzled 7 monoclonal antibody was used to detect the expression and distribution of Frizzled receptors in the spinal cord at the frozen sections of embryonic day(E) 14 embryos.Results: According to the results of gene sequencing of ORF region of Wnt7b, there were differences between the two inbred strains. Among the 8 tissues, there were significant differences in Wnt7b gene expression in tissues of the spinal cord, muscle, spleen and kidney between the two strains. Finally, based on the immunochemistry data, it could be deduced that there were significant differences in the expression level and distribution of Frizzled receptors in the spinal cords between the two strains of mice from embryonic day(E) 14. And especially around the area of neuronal tube, the expression level of Frizzleds receptor in A was obviously higher than that in B6.Conclussion: The differences in the gene expression and gene sequencing suggest that Wnt7b gene must be related to the spinal cord development. That is to say, Wnt7b gene must be a candidate gene for the spinal cord development. And the strong expression of Frizzled receptors is related to the suppression of the spinal cord development, which shows that Wnt7b signal pathway participates in the process of controlling the development of the spinal cord.