原钙黏附蛋白18b基因抑制对斑马鱼神经系统发育的影响

原钙黏附蛋白18b(Protocadherin18b，Pcdh18b)属于钙黏附蛋白家族成员．为了研究pcdh18b基因抑制对斑马鱼神经系统发育的影响，针对pcdh18b的翻译起始位点设计一个吗啡啉修饰的反义寡核苷酸抑制其表达，在斑马鱼受精卵一到二细胞期注射并且验证其有效性．注射后用原位杂交和吖啶橙染色检测神经系统的表型和标志基因的表达．pcdh18b下调使神经前体细胞的标志基因neurog1、神经元标志基因elavl3和神经胶质细胞标志基因gfap的表达均出现下调，中后脑边界的标志基因pax2a和wnt1表达减弱并出现神经管分叉现象，同时与后脑分节相关的基因krox20表达减少．吖啶橙染色显示pcdh18b下调后斑马鱼中脑、后脑及中后脑边界细胞凋亡增多．这些结果表明pcdh18b抑制导致了斑马鱼神经系统发育的异常．

The Effects of Protocadherin18b Down Regulation on Embryonic Neurogenesis in Zebrafish

Protocadherin18b (Pcdh18b) belongs to the protocadherins, which make up the largest subgroup within the cadherin superfamily. To study the role of pcdh18b on embryonic neurogenesis in zebrafish, one type of well designed antisense morpholino oligonucleotide was injected into one or two-cell stage embryos to block the translation of pcdh18b. After injection, the phenotypes of nervous system were monitored by whole mount in situ hybridization and acridine orange staining. Whole-mount in situ hybridization with neurog1, elavl3, gfap and krox20 RNA probes showed that the expression of neural precursor cells, neurons, neuroglia cells and rhombencephalon3, 5 was strikingly affected; meanwhile, the expression of MHB (midbrain-hindbrain boundary) markers pax2a and wnt1 was significantly compromised and showed duplication of neural tube in pcdh18b down regulation group. Acridine orange staining pointed out that down regulation of pcdh18b increased cell apoptosis in midbrain, hindbrain and MHB region. These results suggest that pcdh18b plays an important role in the zebrafish neurogenesis.