Uncovering the Distinct Properties of a Bacterial Type I-E CRISPR Activation System.

Synthetic gene regulators based upon CRISPR-Cas systems offer programmable technologies to control gene expression in bacteria. Bacterial CRISPR activators (CRISPRa) have been developed that use engineered type II CRISPR-dCas9 to localize transcription activation domains near promoter elements. However, several reports have demonstrated distance-dependent requirements and periodical activation patterns that overall limit their flexibility. Here, we demonstrate the potential of using an alternative type I-E CRISPR-Cas system to create a CRISPRa with distinct and expanded regulatory properties. Furthermore, we create the first bacterial CRISPRa system based upon a type I-E CRISPR-Cas and characterize the distance-dependent activation patterns to reveal a distinct and more frequent periodicity of activation.