Why AyeSwitch?

Over the course of the summer, the University of Aberdeen iGem team engineered a novel genetic toggle switch in yeast which is regulated at the translational level and allows mutually exclusive expression of either green or cyan fluorescent protein. Using cell cytometry (FACS) and fluorimetry, we successfully demonstrated gene expression and translational regulation of a fusion of mRNA binding proteins and fluorescent proteins. Deterministic and stochastic models including experimental results and published parameter values predicted that the probability of successful bistability for the switch is 0.96%, but that this can theoretically be improved to a maximum of 51.27% by limiting the variation range of the most sensitive parameters. The models also predicted that to generate switch-like behaviour, co-operative binding of the mRNA binding protein to its mRNA stem loop was essential. These results suggest that a translationally regulated genetic toggle switch is a viable and novel engineering concept applicable to medicinal, environmental and technological problems.