Coupling Cell Communication and Optogenetics: Implementation of a Light-Inducible Intercellular System in Yeast

Abstract

Cell communication is a widespread mechanism in biology, allowing the transmission of information about environmental conditions. In order to understand how cell communication modulates relevant biological processes such as survival, division, differentiation, and apoptosis, different synthetic systems based on chemical induction have been successfully developed. In this work, we coupled cell communication and optogenetics in the budding yeast Saccharomyces cerevisiae. Our approach is based on two strains connected by the light-dependent production of α-factor pheromone in one cell type, which induces gene expression in the other type. After the individual characterization of the different variants of both strains, the optogenetic intercellular system was evaluated by combining the cells under contrasting illumination conditions. Using luciferase as a reporter gene, specific co-cultures at a 1:1 ratio displayed activation of the response upon constant blue light, which was not observed for the same cell mixtures grown in darkness. Then, the system was assessed at several dark/blue-light transitions, where the response level varies depending on the moment in which illumination was delivered. Furthermore, we observed that the amplitude of response can be tuned by modifying the initial ratio between both strains. Finally, the two-population system showed higher fold inductions in comparison with autonomous strains. Altogether, these results demonstrated that external light information is propagated through a diffusible signaling molecule to modulate gene expression in a synthetic system involving microbial cells, which will pave the road for studies allowing optogenetic control of population-level dynamics.

Optogenetic control of pheromone gradients reveals functional limits of mating behavior in budding yeast

“…We first aimed at engineering light-inducible strains that can produce physiological levels of pheromone, by improving on a previous strain design 24 . For this we first engineered wild-type MAT α yeast cells using a CRISPR-based promoter replacement strategy ( see Methods ) to replace the promoter of the two α-factor pheromone-coding genes (MF-α1 and MF-α2) with the P C120 promoter, the activity of which is induced by the light-sensitive transcriptional activator EL222 25 .…”

Genetic modules for α‐factor pheromone controlled growth regulation of Saccharomyces cerevisiae

“…Instead of the synthetic α‐factor used in our study, cellular produced pheromones in a co‐culture could be used as inducers of the FIG1 promoter. For example, an artificial, blue light‐dependent and α‐factor pheromone mediated communication between two S. cerevisiae strains was reported recently [56]. Thereby, activation of the sender cell under blue light conditions led to the secretion of α‐factor, which induced the mating pathway in the receiver cell through binding at the Ste2p GPCR.…”

Optogenetic control of a horizontally acquired region in yeast prevent stuck fermentations

“…Among the available optogenetic tools, the FUN-LOV system enables light-controlled expression of the targeted genes (26). This system has been used to regulate different yeast phenotypes, including flocculation, heterologous protein production, and the mating type signaling pathway (26,31). In this work, we assess the contribution of horizontally acquired genes in fermentation.…”