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.

We furthermore provide a tool for the generation of stable mammalian cell lines under S1-safety regulations. Our viral vector, which we propose as new iGEM RFC enables to introduce any gene of interest stabley into mammalian cell lines. Therefore we provide a fast, easy to handle and safe way of generating stable cell lines.