Application of the yeast pheromone system for controlled cell-cell communication and signal amplification.

AIMS: The aim of the work is to exploit the yeast pheromone system for controlled cell-cell communication and as an amplification circuit in technical applications, e.g. biosensors or sensor-actor systems. METHODS AND
RESULTS: As a proof of principle, we developed recombinant Saccharomyces cerevisiae cells that express enhanced green fluorescent protein (EGFP) in response to different concentrations of the alpha(α)-factor mating pheromone. A respective reporter construct allowing the pheromone-driven expression of EGFP was transformed into the S. cerevisiae strains BY4741 and BY4741 bar1Δ. Upon addition of synthetic α-factor, the fluorescence strongly increases after 4 h. Furthermore, cells with constitutive α-factor expression were able to induce the expression of EGFP in co-cultivation with sensor cells only if both cell types were deleted for the gene BAR1, encoding α-factor protease. For technical applications, the immobilization of functionalized cells may be beneficial. We show that pheromone-induced expression of EGFP is effective in alginate-immobilized cells.
CONCLUSIONS: Based on S. cerevisiae α-factor, we developed a controlled cell-cell communication system and amplification circuit for pheromone-driven expression of a target protein. The system is effective both in suspension and after cell immobilization. SIGNIFICANCE AND IMPACT OF THE STUDY: The developed set of recombinant yeast strains is the basis to apply the yeast pheromone system for signal production and amplification in biosensors or sensor-actor systems.