【摘要】 背景与目的已有的研究证明CRISPR/Cas9(Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated 9)系统是一种能够在哺乳动物细胞中高效操作的新型基因编辑技术,应用人工设计的向导RNA(single-guide RNA,sgRNA)介导外源表达的Cas9蛋白与靶点DNA特异性结合以实现对基因组DNA的切割,被切割后的基因组DNA通过非同源重组或同源重组的方式进行修复,从而实现基因的敲除、或者外源基因的敲入等目标。本研究的目的是应用CRISPR/Cas9技术构建小鼠肺部EZH2基因敲除的动物模型。方法针对EZH2基因的编码区,设计两个靶向EZH2基因Exon3和Exon4的sgRNA,通过慢病毒包装、感染细胞、SURVEYOR assay等一系列体外实验,验证所设计的sgRNA的有效性。应用支气管插管的方式把慢病毒灌注到小鼠肺部,利用免疫组化方法和qRT-PCR进行检测。结果 NIH-3T3细胞的体外实验结果验证了实验所设计的sgEZH2能够有效地在体外细胞系中介导Cas9切割靶DNA;小鼠支气管插管实验及肺部组织免疫组化和qRT-PCR方法检测EZH2基因敲除的效率,发现实验组小鼠肺部组织EZH2表达明显降低。结论本研究成功设计了两条能够敲除EZH2功能的sgRNA,并应用CRISPR/Cas9技术成功建立了肺部EZH2基因敲除的小鼠模型,为研究EZH2的功能和作用机制提供了有效的动物模型。更多还原

【Abstract】 Background and objective It has been proven that CRISPR/Cas9(Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated 9) system was the modern gene-editing technology through the constitutive expression of nucleases Cas9 in the mammalian, which binds to the specific site in the genome mediated by single-guide RNA(sg RNA) at desired genomic loci. The aim of this study is that the animal model of EZH2 gene knockout was constructed using CRISPR/Cas9 technology. Methods In this study, we designed two single-guide RNAs targeting the Exon3 and Exon4 of EZH2 gene. Then, their gene-targeting efficiency were detected by SURVEYOR assay. The lentivirus was perfused into the lungs of mice by using a bronchial tube and detected by immunohistochemistry and qRT-PCR. Results The experimental results of NIH-3 T3 cells verify that the designed sg EZH2 can efficiently effect the cleavage of target DNA by Cas9 in vitro. The immunohistochemistry and qRT-PCR results showed that the EZH2 expression in experimental group was significantly decreased in the mouse lung tissue. Conclusion The study successfully designed two sgRNA which can play a knock-out EZH2 function. An EZH2 knockout animal model was successfully constructed by CRISPR/Cas9 system, and it will be an effective animal model for studying the functions and mechanisms of EZH2.更多还原