Towards engineering RNA turnover in cyanobacteria

Cyanobacteria are photosynthetic microbes that are being investigated as potential biocatalysts for conversion of CO₂ into useful products. Metabolic engineering of cyanobacteria for the production of chemicals has been challanging due to a limited set of tools for expression and control of non-native pathways. Fine-tuning of gene expression and regulation of protein stoichiometry will be required for pathway optimization and chemical production. Messenger RNA (mRNA) are key intermediates during protein production since the steady-state levels of mRNA are crucial for determining the protein translation rate. mRNA are highly labile, with many factors including secondary structure contributing to the overall stability. Cyanobacteria contain a diverse set of exoribonucleases, endoribonucleases, and RNA modifying enzymes that are predicted to function in mRNA turnover. We are examining the diversity of ribonucleases in cyanobacterial genomes and the function of RNases and RNA modifying enzymes in the model cyanobacterium Synechococcus PCC 7002. This work will guide the development of an RNA-based toolkit for post-transcriptional control of endogenous and exogenous pathways.