Summary

We, the iGEM Team Freiburg 2014, have combined the capability of viral vectors for stable gene transfer with the spatial resolution of optogenetics for gene delivery into mammalian cells in a spatio-temporal manner. We generated patterns by illuminating distinct areas in a mammalian cell culture with light of a special wave length leading to the expression of the mouse cationic amino acid transporter (mCAT-1) and infected target cells with the viral vector containing the gene of interest. Only cells that express mCAT-1 were infected by viral particles. Cells transduced with viral particles containing a fluorescent protein (e.g. EGFP) have been visualized with a fluorescent microscope. In the same way, we infected cells with a viral vector containing seap (Secreted embryonic alkaline phosphatase) gene which enables us to generate QR codes on multiple well plates that can be easily read spectrophotometrically.

Our system is based on three parts: The viral vector, which can deliver our genes of interest into mammalian cells and stably integrate them into their genomes; the receptor, which functions as an entry site for the vector and makes gene transfer specific; and the light system, which combines both parts by inducing the receptor expression only in distinct areas of a tissue leading to pattern formation.