Systematic identification of a panel of strong promoter regions from Listeria monocytogenes for fine-tuning gene expression

Abstract

Background Attenuated Listeria monocytogenes (Lm) has been widely used as a vaccine vector in the prevention and treatment of pathogen infection and tumor diseases. In addition, previous studies have proved that the attenuated Lm can protect zebrafish from Vibrio infections, indicating that the attenuated Lm has a good application prospect in the field of aquatic vaccines. However, the limitation mainly lies in the lack of a set of well-characterized natural promoters for the expression of target antigens in attenuated Lm. Results In our study, candidate strong promoters were identified through RNA-seq analysis, and characterized in Lm through enhanced green fluorescent protein (EGFP). Nine native promoters that showed stronger activities than that of the known strong promoter P36 under two tested temperatures (28 and 37 °C) were selected from the set, and P29 with the highest activity was 24-fold greater than P36. Furthermore, we demonstrated that P29 could initiate EGFP expression in ZF4 cells and zebrafish embryos. Conclusions This well-characterized promoter library can be used to fine-tune the expression of different proteins in Lm. The availability of a well-characterized promoter toolbox of Lm is essential for the analysis of yield increase for biotechnology applications.

Expression of a synthetic gene encoding the enhanced green fluorescent protein in various Escherichia coli strains

“…Lanza AM et al used eGFP as a model protein to study conditionspecific codon optimization for protein expression in S. cerevisiae (Lanza et al, 2014). eGFP is often used as a reporter to screen promoters from various organisms, such as Listeria monocytogenes (Ji et al, 2021), S. cerevisiae (de Paiva et al, 2018) or both promoters and terminators from a novel yeast, Kluyveromyces marxianus (Kumar et al, 2021). Cedras G et al used eGFP as a reporter to detect unfolded protein response in S. cerevisiae (Cedras et al, 2020).…”