A remote control for gene transfer

Alteration to a viral vector

In their new method, the Freiburg researchers introduce the genetic information with an optical remote control. As a result, only cells that are illuminated with red light take up the desired genes. To do this, the scientists modified a type of viral vector known as an AAV vector, which is already in clinical use. "We took away the viral vector's ability to dock with cells," Hörner explains, "which is an essential step before the genetic material can be introduced."

To enable this control by light, the researchers have taken a red light photoreceptor system from the plant Arabidopsis thaliana (thale cress). This system consists of two proteins, PhyB and PIF, which bind to each other as soon as PhyB is illuminated with red light. The Freiburg team placed the protein PIF on the surface of the viral vector and modified the other protein PhyB so that it could bind to human cells. Once this modified vector, called OptoAAV, is in a cell culture along with the cell-binding protein, the protein binds to all cells. "If a selected cell is now illuminated with red light, the modified vector can bind to this cell and introduce the target genes into the illuminated cell," Hörner explains.

A key aspect of biological signal research

This new approach allows the researchers to introduce target genes into the desired cells within a tissue culture. The scientists also succeeded in illuminating the tissue culture successively at different locations, thus enabling the targeted introduction of different genes into different cells within a culture. With this technique, it is now possible to control desired processes in individual cells. This is essential for understanding how a single cell communicates with cells in its environment, for example, to control the development or regeneration of an organ. "As these viral vectors become more widely used in the therapeutic field," Weber says, "we think this new technology has the potential to make such biomedical applications more precise."

Cluster of Excellence CIBSS -- Centre for Integrative Biological Signalling Studies

Researchers in the Cluster of Excellence CIBSS -- Centre for Integrative Biological Signalling Studies at the University of Freiburg are investigating the fundamental communication processes that determine multicellular life in humans, animals and plants. In this way, they aim to gain a higher-level, integrative understanding of biological signaling processes in order to develop tailored molecular tools using methods from synthetic and chemical biology to precisely control signaling processes. In this way, the researchers seek to develop strategies for the treatment of cancer using immunotherapies or for resource-conserving crops production, among other things. Maximilian Hörner and Wolfgang Schamel are group leader in the Cluster of Excellence, Wilfried Weber is a member of the speaker team.