Tailor-made sRNAs: a toolbox to control metabolic targets

Summary Pseudomonas putida is a highly attractive production system for industrial needs. Modulation of gene expression is an urgent need to redesign P. putida metabolism for its improvement as biocatalyst at industrial level. We report the construction of a small RNA-based system with potential to be used for different purposes in synthetic biology. Due to their modular composition, design facilities and ability in tuning gene expression, sRNAs constitute a powerful tool in genetic and metabolic engineering. In the toolbox presented here, the synthetic sRNA is specifically directed to any region of a chosen target. The expression of the synthetic sRNAs is shown to differentially modulate the level of endogenous and reporter genes. The antisense interaction of the sRNA with the mRNA results in different outcomes. Depending on the particularity of each sRNA-target mRNA pair, we managed to demonstrate the duality of this system, able either to repress or overexpress a given gene. This system combines a high specificity with a wide applicability due to its ability to modulate the expression of virtually any given gene. By plugging-in and -out genetic circuits, this tailor-made regulatory system can be used to redesign P. putida metabolism, fulfilling an important industrial gap in synthetic biology.