Broad-Spectrum Gene Repression Using Scaffold Engineering of Synthetic sRNAs

Area of Science:

• Synthetic biology
• Molecular biology
• Metabolic engineering

Background:

• Precise gene expression regulation is essential for synthetic biology applications like cell factories and genetic circuits.
• Synthetic small regulatory RNAs (sRNAs) offer translational control but are limited by intrinsic repression capabilities.
• The Hfq-binding module of sRNAs is crucial for their function and stability.

Purpose of the Study:

• To systematically investigate the impact of mutations in the Hfq-binding module of a model sRNA (SgrS) on gene repression efficiency.
• To engineer enhanced sRNA scaffolds for improved gene expression modulation.
• To apply engineered sRNAs for metabolic engineering and strain improvement.

Main Methods:

• Systematic mutagenesis of the SgrS sRNA scaffold, focusing on the A/U-rich sequence, stem, and hairpin loop of the Hfq-binding module.
• Assessing repression efficiency of sRNA mutants using DsRed2 expression as a reporter.
• Constructing a library of synthetic sRNAs with an optimized scaffold targeting various genes in Escherichia coli for cadaverine production.

Main Results:

• Specific alterations in the A/U-rich sequence and stem length of the SgrS scaffold significantly modulated repression efficiency.
• One modified scaffold exhibited a 3-fold stronger repression, while another showed a 3-fold weaker repression compared to the wild-type.
• Application of the enhanced scaffold led to a 27% increase in cadaverine production in Escherichia coli.

Conclusions:

• Engineered sRNA scaffolds can overcome the limitations of intrinsic repression, offering enhanced control over gene expression.
• Optimized synthetic sRNAs hold significant potential for modulating gene expression in microbial hosts.
• This approach is valuable for strain improvement and enhancing the production of target compounds in metabolic engineering.