High-level transgene expression in neurons by lentivirus with Tet-Off system.

We developed novel lentiviral vectors by using "Tet-Off system" and succeeded in achieving high-level and neuron-specific gene transduction in vivo. One week after viral injection into the rat neostriatum, the GFP expression was almost completely neuron-specific and about 40 times higher than the expression of a conventional lentiviral vector. High transcriptional activity and neuronal specificity were sustained for up to 8 weeks. Furthermore, neuronal processes of the infected neurons were efficiently visualized by adding a plasma membrane-targeting signal to GFP. These results suggest that the present method is valuable for strong gene transduction and clear visualization of neurons in vivo.