Influence of different promoters on expression of transgene containing MAR expression vector in recombinant CHO cells / 重庆医学

Objective To investigate the effect of different promoters on the expression level of transgene containing MAR expression vector in recombinant CHO cells.Methods The CMV promoter and 3-globin MAR were amplified by PCR,then CMV promoter was replaced the SV40 promoter in pCAT1 for constructing the expression vector droved by CMV promoter.The control vectors of pCAT1 and pCAT2 without containing MAR were simultaneously transfected into the CHO cells.Then the stably transfected cell line was screened by G418.The CAT gene expression level was analyzed by ELISA.Results The expression level of CAT enzyme in the cells transfected with MAR-containing vectors was increased compared with the cells transfected by pCATG and pCAT3 vectors without containing MAR,which were increased by 1.75 and 1.25 times respectively(P＜0.05);but CAT enzyme expression level in the pCAT1 transfected cells droved by SV40 promotor with the MAR-containing expression vectors was 1.4 times higher than that in the pCAT2 vector droved by the CMV promoter(P＜0.05).Conclusion MAR can enhance the transgene expression level in stably recombinant CHO cells,and the promoting efficiency of SV40 promoter and MAR combination is superior to that of CMV promoter and MAR combination.

A Gene and Neural Stem Cell Therapy Platform Based on Neuronal Cell Type-Inducible Gene Overexpression

PURPOSE: Spinal cord injury (SCI) is associated with permanent neurological damage, and treatment thereof with a single modality often does not provide sufficient therapeutic outcomes. Therefore, a strategy that combines two or more techniques might show better therapeutic effects. MATERIALS AND METHODS: In this study, we designed a combined treatment strategy based on neural stem cells (NSCs) introduced via a neuronal cell type-inducible transgene expression system (NSE::) controlled by a neuron-specific enolase (NSE) promoter to maximize therapeutic efficiency and neuronal differentiation. The luciferase gene was chosen to confirm whether this combined system was working properly prior to using a therapeutic gene. The luciferase expression levels of NSCs introduced via the neuronal cell type-inducible luciferase expression system (NSE::Luci) or via a general luciferase expressing system (SV::Luci) were measured and compared in vitro and in vivo. RESULTS: NSCs introduced via the neuronal cell type-inducible luciferase expressing system (NSE::Luci-NSCs) showed a high level of luciferase expression, compared to NSCs introduced via a general luciferase expressing system (SV::Luci-NSCs). Interestingly, the luciferase expression level of NSE::Luci-NSCs increased greatly after differentiation into neurons. CONCLUSION: We demonstrated that a neuronal cell type-inducible gene expression system is suitable for introducing NSCs in combined treatment strategies. We suggest that the proposed strategy may be a promising tool for the treatment of neurodegenerative disorders, including SCI.

Generation of HIV-1 based bi-cistronic lentiviral vectors for stable gene expression and live cell imaging.

The study of protein-protein interactions, protein localization, protein organization into higher order structures and organelle dynamics in live cells, has greatly enhanced the understanding of various cellular processes. Live cell imaging experiments employ plasmid or viral vectors to express the protein/proteins of interest fused to a fluorescent protein. Unlike plasmid vectors, lentiviral vectors can be introduced into both dividing and non dividing cells, can be pseudotyped to infect a broad or narrow range of cells, and can be used to generate transgenic animals. However, the currently available lentiviral vectors are limited by the choice of fluorescent protein tag, choice of restriction enzyme sites in the Multiple Cloning Sites (MCS) and promoter choice for gene expression. In this report, HIV-1 based bi-cistronic lentiviral vectors have been generated that drive the expression of multiple fluorescent tags (EGFP, mCherry, ECFP, EYFP and dsRed), using two different promoters. The presence of a unique MCS with multiple restriction sites allows the generation of fusion proteins with the fluorescent tag of choice, allowing analysis of multiple fusion proteins in live cell imaging experiments. These novel lentiviral vectors are improved delivery vehicles for gene transfer applications and are important tools for live cell imaging in vivo.