Figure 1

Construction of the CRISPRi system for controlling gene expression.
(A) Sequence of the designed sgRNA template. sgRNA targets the non-template DNA strand of the gene-coding region. Base-pairing nucleotides (20 bp) are shown in orange. The dCas9-binding hairpin is in blue. The PAM sequence is shown in red. The Trc promoter is shown in grey. (B) This CRISPRi system consists of an inducible dCas9 protein and a designed sgRNA chimera. The dCas9 mutant gene contains two silencing mutations of the RuvC1 and HNH nuclease domains. The sgRNA chimera contains four functional domains: a Trc-inducible promoter, a 20-nucleotide (nt) complementary region for specific DNA binding, a 42-nt dCas9-binding hairpin and a 40-nt transcription terminator derived from S. pyogenes15.