CRISPRi-mediated tunable control of gene expression level with engineered single-guide RNA in Escherichia coli.

Precise control of gene expression is essential for flux redistribution in metabolic pathways. Although the CRISPR interference (CRISPRi) system can effectively repress gene expression at the transcriptional level, it has still been difficult to precisely control the level without loss of specificity or an increase in cell toxicity. In this study, we developed a tunable CRISPRi system that performs transcriptional regulation at various levels.