Optogenetics, a novel technology that allows temporal and spatial induction of gene expression by the use of light, is of growing importance for fundamental research and clinical applications. However, its biggest limitation is the time consuming introduction of transgenes into organisms or cell lines. In contrast, easy but unspecific gene delivery can be achieved by viral vectors. We, the iGEM Team Freiburg 2014, combine the advantages of both approaches – the temporal and spatial resolution of optogenetics, and the simplicity of gene transfer offered by viruses.

To this end we designed a system where the entry of a virus is enabled or prevented by exposing the target cells to light of distinct wavelengths.

In principle, the AcCELLerator bridges the gap between both systems by the light induced expression of a receptor that serves as the entry point for the virus. The components of the system and how they work together are briefly presented below.

Light induced expression of target genes bases on a system that consists of mainly two parts: One, a complex of LOV2 fused to Gal4DBD constantly located  at a specific DNA sequence, the Gal4UAS. While in the dark, Jα chain is not exposed, therefore the ePDZ-VP-16 domain can not be recruited and there is no detectable gene expression.