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. 2022 Feb 21;50(5):2836–2853. doi: 10.1093/nar/gkac099

Figure 2.

Figure 2.

AcrIIA24–32 are specific inhibitors of the Streptococcus CRISPR–Cas9 system. (A) Schematic view of phage plaque assays to investigate whether AcrIIA24–32 have broad-spectrum activity on diverse type II-A, II-B and II-C Cas9 orthologs. Escherichia coli carrying plasmids for expressing Cas9, sgRNA and Acr were challenged with the CRISPR-targeted phage T4. The gene 23 of phage T4 was targeted by different Cas9 orthologs (abbreviated by strain names). (B) Phage plaque assays were performed with 10-fold serial dilutions of phage T4 (black circles) to assess the inhibition of different Acr proteins against diverse type II-A (SpyCas9, St1Cas9, St3Cas9 and SaCas9), II-B (FnCas9) and II-C (NmeCas9) Cas9 orthologs. (C) A matrix showing the inhibitory activity of Acrs against diverse Cas9 orthologs in phage plaque assays. The degree of blue represents the inhibitory activity of indicated Acrs against Cas9 orthologs (e.g. the cell with darkest blue indicates the given Acr with strong inhibition on Cas9). Values of this figure represent the mean of at least three biological replicates.