Design and Characterization of Synthetic, Minimal Promoters in Yeast

Promoters are critical to successful engineering in the eukaryotic production platform Saccharomyces cerevisiae. For decades, native promoters and their mutants have been used for metabolic engineering and synthetic biology efforts.  However, native promoters are limited in expression range and vulnerable to cellular regulation, and mutants of these promoters inherently have high sequence homology.  Moreover, these promoters are bulky elements--usually hundreds of base pairs long.  To address these issues, we sought to develop non-homologous, purely synthetic, minimal promoters for yeast.  To do so, we apply a hybrid promoter approach to a unique collection of library-derived promoter elements.  This set includes constitutive and inducible promoters driving expression as strong as native promoters, but in less than 1/3 of the DNA sequence.  In doing so, we generate the shortest promoters described to date and develop a set that shows minimal context specificity.  This work builds a framework for designing modular, minimal promoters with desired expression traits.