Dual Input-Controlled Synthetic mRNA Circuit for Bidirectional Protein Expression Regulation

Synthetic mRNA circuits manipulate cell fate by controlling output protein expression via cell-specific input molecule detection. Most current circuits either repress or enhance output production upon input binding. Such binary input-output mechanisms restrict the fine-tuning of protein expression to control complex cellular events. Here we designed mRNA circuits using enhancer/repressor modules that were independently controlled by different input molecules, resulting in bidirectional output regulation; the maximal enhancement over maximal repression was 57 fold. The circuit either enhances or represses protein production in different cells based on the difference in the expression of two microRNAs. This study examined novel bidirectional circuit designs capable of fine-tuning protein production by sensing multiple input molecules. It also broadened the scope of cell manipulation by synthetic mRNA circuits, facilitating the development of mRNA circuits for precise cell manipulation and providing cell-based solutions to biomedical problems.

Automated summary

Synthetic mRNA circuits control output protein expression by detecting specific input molecules in cells. Existing circuits either enhance or repress protein production upon input binding, but this binary mechanism limits precise control. In this study, bidirectional mRNA circuits were designed to independently control enhancer and repressor modules using different input molecules, resulting in fine-tuning of protein expression. This research expands the capabilities of synthetic mRNA circuits for precise cell manipulation and provides cell-based solutions to biomedical problems.