摘要:
目的 利用CRISPR/Cas9技术,构建靶向精氨酸甲基转移酶3(PRMT3)的基因编辑质粒,建立prmt3基因稳定敲除的A549细胞株,检验prmt3基因敲除效率及其对A549细胞增殖的影响.方法 设计靶向prmt3基因的sgRNA序列,将合成的片段克隆到CRISPR/Cas9质粒载体LentiCRISPR中,挑取单克隆进行测序验证.将构建好的重组质粒和空载体分别进行慢病毒包装,并感染A549细胞,利用嘌罗霉素进行筛选获得PRMT3稳定敲除细胞株,Western印迹检测细胞中PRMT3蛋白的敲除效率.将敲除PRMT3的A549细胞进行单克隆分选,分别利用平板克隆形成实验检测PRMT3敲除后细胞增殖能力,平板划痕实验检测其迁移能力,流式细胞技术检测细胞周期的变化,质谱进行蛋白质组学分析,初步筛查PRMT3可能的底物.结果 经测序验证,成功构建了靶向prmt3基因的LentiCRISPR-PRMT3-sgRNA质粒.经Western印迹检测,A549 PRMT3敲除株中PRMT3的蛋白表达水平明显降低.经单克隆分选,成功获得PRMT3完全敲除的A549细胞株.PRMT3敲除导致A549细胞的克隆形成能力明显增强,细胞迁移能力不变,细胞周期发生G2/M期阻滞.进一步用蛋白质组学的方法初步鉴定了PRMT3可能的底物.结论 利用CRISPR/Cas9技术成功构建了PRMT3稳定敲除的A549细胞株,发现PRMT3能调控细胞周期和增殖,并对其分子机制做了初步探索.%Objective To construct plasmids for knock-out of protein arginine methyltransferase 3 (prmt3) gene using CRISPR/Cas9 gene editing method and examine the effect of prmt3 knockout on the proliferation of human non-small cell lung cancer(NSCLC)A549 cells.Methods Synthesized sgRNA oligos targeting prmt3 gene were cloned into LentiCRISPR vector and positive constructs confirmed by sequencing later .After infection with the packaged virus , A549 cells were screened with puromycin , and then the single clones were isolated .The protein level of PRMT3 in individual cell clones was analyzed with Western blot . Biological assay of clone formation , wound healing , flow cytometry assay and mass spectrometry ( MS) analysis were used to compare cellular proliferation behavior changes between control cells and cells with prmt3 gene knockout .Results The LentiCRISPR plasmids targeting prmt3 gene were confirmed by sequencing , and the PRMT3 protein level was significantly decreased in PRMT 3 KO cells compared with control cells .Depletion of PRMT3 promoted cell proliferation and led to cell cycle arrest at G 2/M phase, but had no influence on cell migration .Besides, some PRMT3 substrate candidates were identified with mass spectrum assays .Conclusion A549 cells with prmt3 gene knockout based on CRISPR/Cas9 are successfully established .PRMT3 can regulate cell cycle and proliferation .