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)重复序列的脆性部位的关联，并建立这种疾病的动物模型，我们在转基因中产生了携带p(CCG)重复序列的转基因小鼠。以CCG和CGG三核苷酸重复低聚物(40个重复)为模板，用聚合酶链式反应扩增出不间断的30、60和100个重复序列的DNA片段。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。无论使用多少重复次数，这些含有CCG重复的转基因小鼠的重复长度随着传播而发生变化。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，我们可能需要考虑使用更长的CCG重复在构建或因素以外的三核苷酸重复长度单独解释CCG的不稳定性，并建立一个模型小鼠。

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.