RT Journal Article SR Electronic T1 Engineering a circular riboregulator in Escherichia coli JF bioRxiv FD Cold Spring Harbor Laboratory SP 008987 DO 10.1101/008987 A1 William Rostain A1 Shensi Shen A1 Teresa Cordero A1 Guillermo Rodrigo A1 Alfonso Jaramillo YR 2014 UL http://biorxiv.org/content/early/2014/09/25/008987.abstract 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.