BACKGROUND:Islet beta cell replacement therapy is one of the most promising approaches for treating type 1 diabetes mellitus. However, its large scale application is hampered by a shortage of islet beta cells for transplantation. Pluripotent stem cells are one of ideal seed cells for islet beta cell replacement therapy, but pancreatic beta-cell differentiation is time-consuming and labor-intensive. OBJECTIVE:To construct a high efficient pancreatic and duodenal homeobox 1 (Pdx1)/insulin dual-reporter vector and to monitor the key genes expression during pancreatic beta-cell differentiation from pluripotent stem cells. METHODS:In order to construct a high efficient Pdx1/insulin dual-reporter vector, puromycin resistance gene was firstly introduced into pTiger vector, and then the original 410 bp mouse Ins1 promoter of the vector was replaced by 646 bp mouse Ins1 promoter. Finally, the dual-reporter vector was transduced into INS-1 and human induced pluripotent stem cells to testify its function. RESULTS AND CONCLUSION:The high efficient Pdx1/insulin dual-reporter vector was constructed successfully. The vector successfully acquired puromycin resistance gene and high gene expression efficacy of insulin in INS-1 cells. The specific gene expression pattern of Pdx1/insulin was first found in INS-1 cells. To conclude, the real-time monitoring function of Pdx1/insulin expression is preliminarily confirmed during pancreatic beta-cell differentiation.

To establish a gene regulation system compatible with biopharmaceutical industry and gene therapy, we constructed a fusion protein of biotin ligase from Bacillus subtilis (BS-BirA) and the trans-activation domain, and used its expression vector as the regulatory vector. Meanwhile, BS-BirA-specific operators were ligated upstream of attenuated CMV promoter to obtain the response vector. In this way, a novel eukaryotic gene regulation system responsive to biotin was established and named BS-Biotin-On system. BS-Biotin-On system was further investigated with the enhancing green fluorescent protein (EGFP) as the reporter gene. The results showed that our system was superior to the current similar regulation system in its higher induction ratio, and that the expression of interest gene could be tuned in a rapid and efficient manner by changing the biotin concentrations in the cultures, Our results show that the established system may provide a new alternative for the exogenous gene modulation.
Bacillus subtilis ; Biotin ; chemistry ; Eukaryotic Cells ; metabolism ; Gene Expression Regulation ; Genetic Vectors ; Promoter Regions, Genetic ; Trans-Activators