PT - JOURNAL ARTICLE AU - William Rostain AU - Shensi Shen AU - Teresa Cordero AU - Guillermo Rodrigo AU - Alfonso Jaramillo TI - Engineering a circular riboregulator in <em>Escherichia coli</em> AID - 10.1101/008987 DP - 2014 Jan 01 TA - bioRxiv PG - 008987 4099 - http://biorxiv.org/content/early/2014/09/25/008987.short 4100 - http://biorxiv.org/content/early/2014/09/25/008987.full AB - Circular RNAs have recently been shown to be important gene expression regulators in mammalian cells. However, their role in prokaryotes remains elusive. Here, we engineered a synthetic riboregulator that self-splice to produce a circular molecule, exploiting group I permuted intron-exon (PIE) sequences. We demonstrated that the resulting circular riboregulator can activate gene expression, showing increased dynamic range compared to the linear form. We characterized the system with a fluorescent reporter and with an antibiotic resistance marker. Thanks to the increased regulatory activity by higher stability, isolation due to self-splicing, and modularity of PIE, we envisage engineered circular riboregulators in further synthetic biology applications.