Construction of short synthetic promoters for optimization of ovalbumin expression level in Saccharomyces cerevisiae

Saccharomyces cerevisiae, a common eukaryotic model microorganism that is generally recognized as safe, is widely employed for the heterologous expression of edible and therapeutic proteins. Promoters are crucial components of protein expression systems and have been extensively studied. In this study, we characterized 93 endogenous promoters using a fluorescence characterization system with a high signal-to-noise ratio. The core promoter sequences of strong constitutive promoters were concatenated with different upstream activating sequences (UASs), ultimately resulting in a set of short constitutive promoters exhibiting 30% higher intensity than that of the commonly used strong constitutive promoter P_TDH3. Similarly, a set of short inducible promoters with 20% higher intensity than that of the widely used inducible promoter P_GAL1 was obtained by linking the core promoter sequences of strong inducible promoters with UAS_GAL1. These short promoters were used to optimize ovalbumin expression. In conclusion, this study achieved shorter promoters with higher strength compared to that of the commonly used constitutive and inducible promoters in S. cerevisiae, thus laying the foundation for the rational design and simplification of the expression system.