仅采用 PCR 进行分子克隆的方法探索

摘要

目的：针对目前各种费时且易失败的克隆方法和价格昂贵的试剂盒等问题,对一种仅采用聚合酶链反应(polymerase chain reaction,PCR)分子克隆方法进行了探索。方法利用高保真的 DNA 聚合酶具有3'-核酸外切酶活性的特点,采用 PCR 把载体和插入片段扩增出来,二者的扩增产物先加限制性内切酶 DpnI 后再按一定比例混合来消化甲基化的 DNA 模板,最后把DpnI 消化产物直接转化到感受态细胞来得到克隆基因。结果是一种简单、高效、可靠、且仅采用 PCR 的分子克隆方法,并利用此方法成功地把构建在载体 pET 上的α-突触核蛋白全长基因和构建在 pCDNA3.1上的乙酰胆碱受体亚基的全长基因分别重新构建在载体 pGEX-4T-1和 pGEMHE 上。结论在 PCR 扩增时能够通过引物设计来确定克隆位点,所以该方法可以把任何 DNA片段插入到质粒载体内的任何位置,而不需要考虑载体多克隆位点限制的问题。此外,该方法省去了传统的酶切消化、纯化回收和连接过程。%Objective Due to the high cost in both time and money in gene cloning, a simple molecular cloning method based on polymerase chain reaction(PCR) is presented. Methods The vector and insert are amplified by PCR separately. After DpnI digestion of the mixture of the amplified vector and insert to eliminate the DNA templates used in PCR reactions, the mixture is directly transformed into competent E. coli DH5 cells to obtain the desired clones. Results Here we report a highly simplified,reliable and efficient PCR-based cloning technique to subclone total α-synuclein gene(cDNA) from vector pET into vector pGEX-4T-1, and place total nAChRβ2 gene from vector pCDNA3. 1 into vector pGEMHE. Conclusion This technique has many advantages over other cloning methods. First, we can insert any interested DNA sequences into a vector anywhere by primer designation, and it does not need to consider the restriction of multiple cloning site. Second, there is no need for any specialized enzyme digestion, gel purification of PCR product and linearized vector and enzyme ligation.