Light-activated gene expression

Light is an attractive mode of gene regulation that provides high spatio-temporal resolution with relatively low levels of toxicity. In order to add to the genetic toolbox, we characterized a novel light-activated gene regulation system that combines the DNA-binding region of LacI with the light inducible LOV (Light Oxygen Voltage) domain. The characterization assay was performed by measuring the fluorescence output of a LacILOV-regulated reporter under blue light illumination. We then computationally modelled the structure of our protein and identified key mutations to optimize its activity.

Identifying and informing stakeholders

In order to inform future applications of our tool, we identified key stakeholders that would be impacted by potential uses of LacILOV including experts, businesses, the public and future scientists. To this end, we developed resources to promote interest and meaningful interdisciplinary dialogue between researchers and the public. This was achieved through a podcast series exploring the interaction of synthetic biology with different disciplines, a synthetic biology workshop for burgeoning scientists and an iconathon to promote collaborations between scientists and artists.

Applying LacILOV to human gene editing

However, in order to demonstrate the utility of our tool, we decided to focus on human gene editing, an area that would benefit from stringent gene regulation. We designed and modelled a light activated switch to control CRISPR-Cas9 activity by putting guide RNAs and anti-CRISPR proteins under LacILOV-regulated promoters. We then investigated the ethical and technical concerns of our stakeholders through an interview series involving scientists, engineers, physicians, advocacy groups and religious leaders. Based on technical feedback, we identified an accurate light delivery system as a key technical barrier to validating our tool in mammalian cultures, the next step in its translation to the clinic. We therefore designed and prototyped hardware to pave the way for our system to be used in stem cell cultures. Secondly, based on the different opinions on the ethical applications of human gene editing, we identified the need for clear ethical guidelines. Using the recommendations of the 2017 report by the National Academy of Science, we developed an ethical guide for future iGEM teams.