miRNA-Mediated Regulation of Synthetic Gene Circuits in the Green Alga <i>Chlamydomonas reinhardtii</i>

MicroRNAs (miRNAs), small RNA molecules of 20–24 nts, have many features that make them useful tools for gene expression regulationsmall size, flexible design, target predictability, and action at a late stage of the gene expression pipeline. In addition, their role in fine-tuning gene expression can be harnessed to increase robustness of synthetic gene networks. In this work, we apply a synthetic biology approach to characterize miRNA-mediated gene expression regulation in the unicellular green alga Chlamydomonas reinhardtii. This characterization is then used to build tools based on miRNAs, such as synthetic miRNAs, miRNA-responsive 3′UTRs, miRNA decoys, and self-regulatory loops. These tools will facilitate the engineering of gene expression for new applications and improved traits in this alga.