Mxi1基因敲除小鼠遗传背景的转换研究

Genetic background transformation in Mxi1 gene knockout mice

目的对FVB/N品系Mxi1基因敲除(knock out,KO)(Mxi1^(^(-/-)))小鼠进行遗传背景转换,为研究疾病发病机制提供更多种类的基因修饰小鼠。方法将FVB/N品系杂合子小鼠(Mxi1^(+/-))与异性C57BL/6品系野生型(wild type,WT)小鼠(Mxi1^(+/+))杂交,获得杂合子F1代后将其与C57BL/6品系Mxi1+/+小鼠回交,再选择F2杂合子与C57BL/6品系Mxi1^(+/+)小鼠回交,依此再回交8次后,子代互交。利用鼠尾DNA进行基因型鉴定及微卫星DNA(msDNA)检测,组织信使RNA(mRNA)和组织蛋白检测背景转换效率。结果基因型鉴定为Mxi1^(-/-)的互交子代小鼠msDNA检测结果与WT型C57BL/6小鼠一致,与FVB/N小鼠不同。PCR和Western印迹结果显示,随机选取的任意自交子代纯合子小鼠体内不表达Mxi1的mRNA和蛋白质,成功获得C57BL/6品系Mxi1^(-/-)小鼠。结论通过杂交-回交的方式成功获得的新品系Mxi1^(-/-)小鼠能稳定地将突变基因传递给子代。这一成果为疾病动物模型的建立提供了更多的选择。

Objective To breed various genetically modified mice for pathogenetic studies by investigating the genetic background conversion of Mxi1 knockout（ KO）（ Mxi1^（-/-）） mice of FVB/N strain. Methods FVB/N strain Mxi1 heterozygous mice（ Mxi1^（＋/-）） were hybridized with C57BL/6 strain wild-type（ WT） mice（ Mxi1＋ / ＋） of the opposite sex.The mice of heterozygous F1 were backcrossed with C57 BL /6 strain Mxi1＋ / ＋mice. Then,the mice of heterozygous F2 were backcrossed with C57 BL /6 strain Mxi1^（＋/＋）mice. The above backcross process was repeated 8 times. After that,the Mxi1^（＋/-）mice were reciprocally crossed. The DNA collected from the mouse tail was identified and ms DNA was detected.Tissue messenger RNA（ mRNA） and protein were tested to evaluate the efficiency of background conversion. Results The mice generated by reciprocal cross,whose genotype was identified as Mxi1^（-/-）,had the same ms DNA test results as C57 BL/6 strain WT mice. However,it was different from that of FVB/N mice. PCR and Western blotting testing results showed random mice generated by reciprocal cross had no Mxi1 mRNA or protein expression. These results indicated that C57 BL /6 strain Mxi1^（-/-）mice were successfully bred. Conclusion New strain Mxi1^（-/-）mice are generated by the crossbackcross process and their mutated gene could be passed on to their offspring. This work provides another option for the establishment of the animal disease model.