Conditional gene expression: Intelligent designs

A novel inducible lentiviral system for multi-gene expression with human HSP70 promoter and tetracycline-induced promoter

Despite lentiviral system's predominance, its ultimate potential for gene therapy has not been fully exploited. Currently, most lentivirus vectors are non-inducible expression system or single-gene-induced system, which limits the extensive application in gene therapy. In this study, we designed a novel lentiviral vector containing HSP70 promoter and TRE promoter. Compared to traditional lentiviral vectors and inducible vectors, our controllable system has many advantages. Firstly, it contains multiple gene or shRNA targets. Secondly, genes expression is on/off in response to heat shock and DOX induction in time of need respectively with high effectivity and sensitivity. Thirdly, TRE promoter and HSP70 promoter can work with no interference from each other in the same inducible lentiviral vector. In addition, our study also shows that our novel vector has a higher downstream gene expression efficiency than co-transfection method and can co-position multi-genes in single cell effectively. Finally, we propose four derived models based on our vector at the end, which may be useful in biological research and clinical research in the future. Therefore, we believe that this novel lentiviral system could be promising in gene therapy for tumor.

Multiple platforms of a HIV-2 derived lentiviral vector for expanded utility

Using the Indian Human immunodeficiency virus type 2 (HIV-2) isolate derived lentiviral vector (LV) system reported earlier, we have derived multiple differently configured transfer vectors. Among the features imparted, the novel ones include a blue/white colony screening platform, a shorter vector backbone candidate and availability of default dual tags. Simultaneously, panels with different utilities were also made using this LV. These include neomycin or puromycin or hygromycin selection markers, with options of default promoter, dual multiple cloning site (MCS) availability and drug inducible transgene expression. All the transfer vectors contain the main MCS with the option of single step sub-cloning of a PCR amplified transgene cassette by T/A cloning strategy apart from cohesive and blunt end cloning sites, as described for the original parent vector. Each transfer vector format was tested by appropriate transgene expression function by transduction of target cells. This is the most comprehensive HIV-2 based lentiviral vector system developed so far and it will significantly aid in preferential applications and thus increase its utility as a versatile system for gene transfer technology.

The power of reversibility regulating gene activities via tetracycline-controlled transcription

Tetracycline-controlled transcriptional activation systems are widely used to control gene expression in transgenic animals in a truly conditional manner. By this we refer to the capability of these expression systems to control gene activities not only in a tissue specific and temporal defined but also reversible manner. This versatility has made the Tet regulatory systems to a preeminent tool in reverse mouse genetics. The development of the technology in the past 15 years will be reviewed and guidelines will be given for its implementation in creating transgenic rodents. Finally, we highlight some recent exciting applications of the Tet technology as well as its foreseeable combination with other emerging technologies in mouse transgenesis.