具有不同酶活性并可抵抗特异shRNA降解的nm23-H1真核表达载体的构建和表达

BACKGROUND AND OBJECTIVE: It has been proven that nm23-H1 gene was a tumor metastatic suppressor gene. However, it's molecular mechanism of suppressing metastasis remains unexplored. There is a closely relationship between the abnormality of stucturs and functions of nm23-H1 gene, and cancer invasion and metastasis. We have constructed the vector with nm23-H1-shRNA and the vector with nm23-H1cDNA resistant to the specific shRNA. So, we plan to construct shRNA-resistant eukaryotic expression vector of nm23-H1 gene by site-directed mutagenesis, rescue experiment was performed to verify the nm23-H1 gene expression, and to provide basement for studying the biochemical mechanisms of nm23-H1 gene. METHODS: Site-directed mutagenesis of nm23-H1 gene was performed by overlap extension PCR method. Pure plasmid containing gene of nm23-H1 (shRNA-resistant) was prepared. The desired five mutations were constructed and cloned into the eukaryotic vector pcDNA3.1Hygro(+). The human lung adenocarcinoma cell A549/nm23-H1-shRNA (stable nm23-H1 gene silencing) was transfected with the five mutants, and the expression of the mutant proteins was determined by Western blot. RESULTS: Five eukaryotic expression vectors (shRNA-resistant) of nm23-H1, nm23-H1(S44A), nm23-H1(P96S), nm23-H1(H118F), nm23-H1(S120G), nm23-H1(P96S-S120G), were successfully constructed. The results of DNA sequencing confirmed that the base sequences of the genes were completely concordant with experiment design. The expression of nm23-H1 mutant proteins was verified by Western blot. CONCLUSION: Five eukaryotic expression vectors (shRNA-resistant) of nm23-H1 gene were successfully constructed, and the mutant proteins were verified. The site-directed mutagenesis technical of overlap extension PCR is a efficient, simple and economical method.