中文摘要：

目的：构建变形链球菌gcp基因突变菌株,以便研究变形链球菌gcp基因功能。方法：厌氧培养变形链球菌UA159,以前期研究中pMD19T-gcp为模板,PCR扩增gcp基因内部序列,连接自杀载体pVA8912,酶切鉴定;将鉴定正确的质粒转化变形链球菌UA159,挑取阳性克隆,提取基因组DNA,用PCR结合酶切鉴定。结果：发现PCR产物及插入片段大小与预期值相符,表明成功构建了重组质粒pVA8912/gcp;经PCR鉴定：gcp基因失活株基因组中gcp基因内部成功插入了重组载体片段。结论：成功构建了变形链球菌gcp基因失活株,为该基因功能的研究奠定了基础。

英文摘要：

Objective： To construct streptococcus Mutans with gcp gene knockout mutant. Methods： pMD19T-gcp was served as template, and PCR was performed to amplify gcp sequence （873bp）, followed by connection with to T vector, The gene frame was inserted into suicide vector pVA8912, Then pVA8912/gcp was transformed into UA159 and positive clone was selected. The selected clone was then verified by PCR and enzymatic analysis on the extracted genomic DNA of the positive clone. Results： Enzymatic analysis found the product of PCR had the same size as the inserted piece, which implies the construction of pVA8912/gcp was successful.The gcp mutant was identified by PCR. Conclusion： The construction of S. Mutans with gcp gene knockout mutant was successful which provides a reference for the study of the function of gcp gene.