Basic study for establishment of the chromosome deletion model mouse

为了深入了解染色体缺失与定位于p（CCG）重复的脆性位点（其随着传播而扩展）的关联，并开发这种疾病的动物模型，我们已经产生了在转基因中携带p（CCG）重复的转基因小鼠。以CCG和CGG三核苷酸重复寡聚体（40个重复）为引物和模板，通过PCR扩增出不间断的30、60和100个重复的p（CCG）DNA片段。通过将这些合成的p（CCG）DNA片段连接到由巨细胞病毒增强子、β-肌动蛋白启动子、β-珠蛋白内含子、LacZ和polyA信号序列组成的LacZ高表达载体的5 '-非翻译区来制备构建体。无论使用的重复序列的数量如何，在转基因小鼠中这些含有CCG重复序列的转基因在传递时没有显示重复序列长度的变化。在转基因小鼠中既没有观察到染色体缺失，也没有观察到转基因的表型效应。因此，我们可能需要考虑在构建体中使用更长的CCG重复序列或单独使用三核苷酸重复序列长度以外的因素来解释CCG不稳定性并创建模型小鼠。

To gain insight into the association of a chromosome deletion with a fragile site localized to the p (CCG) repeat which expand with transmission and to develop an animal model of this disorder, we have generated transgenic mice carrying p (CCG) repeats in the transgene. Uninterrupted 30-, 60-, and 100-repeats p (CCG) DNA fragment were amplified by PCR using CCG and CGG trinucleotide repeat oligomers (40repeat) as both primers and template. Constructs were prepared by ligation of these synthesized p (CCG) DNA fragments into the 5'-untranslated region of LacZ high expression vector composed of cytomegalovirus enhancer, beta-actin promoter, beta-globin intron, LacZ and polyA signal sequence. Regardless of the number of repeat used, these transgenes containing the CCG repeat in transgenic mice showed on change in repeat length with transmission. Neither the chromosome deletion nor phenotypic effects of the transgenes were observed in transgenic mice. Therefore, we may need to consider the use of longer CCG repeat in the constructs or factors other than trinucleotide repeat length alone to explain CCG instability and create a model mouse.