Construction of a Tl-CRISPRi Genetic Circuit in Bacteria for Translation-Level Gene Knockdown

The Tl-CRISPRi system, which harnesses the specific RNA-binding activity of CRISPR-dCas13, has been recently developed for translation-level gene knockdown in bacteria. By introducing spacers complementary to the translation initiation region of the mRNA, dCas13 can be directed to block the ribosome and inhibit the translation of that mRNA. Here, we discuss how to construct the Tl-CRISPRi genetic circuit and implement this system for gene knockdown. This chapter describes how to design spacer sequences and install them into the guide RNA expression plasmid. Also, we describe how to mutate the handle of gRNA to achieve tunable knockdown of a target gene. By following the method described in this chapter, we anticipate that a precise and controllable knockdown of a target gene in bacterial cells can be performed in a programmable manner.