Abstract: Objective: To construct expressive vector containing double suicide genes targeted by MDR1 promoter for the purpose of targeted gene therapy for MDR leukemia. Methods: The DNA fragment of MDR1 promoter was amplified from genome DNA of K562/A02 cells with PCR and was inserted into the upstream of CD-TK to construct pcDNA3MDR1PromoterCDTK.This recombinant vector was transfected into K562, K562/A02 cells by means of liposome. PCR and RTPCR were resorted to identify the integration and expression of CD and TK genes. Results: The length and sequence of MDR1 promoter amplified by PCR were confirmed by DNA sequencing. The pcDNA3MDR1PromoterCD-TK expression vectors were constructed successfully. PCR proved double suicide genes were integrated into K562/A02 and K562 cells. RT-PCR revealed that CD and TK genes expressed in K562/A02/CD-TK cells, whereas not in K562/CDTK cells. Conclusion: Construction of expressive vector containing double suicide genes targeted by MDR1 promoter and its specific expression in K562/A02 cell provide a sound basis for targeted gene therapy for MDR leukemia.

Key words: Genes, MDR, Promoter, Sucide gene, Plasmid