Extended Data Figure 3. Type III-A CRISPR-Cas immunity against plasmids carrying inducible targets.

(a) S. aureus TB4 strains were transformed with pCRISPR plasmids carrying the dcsm3/dcsm6 or the dcas10/dcsm3/dcsm6 mutations in the type III-A CRISPR-Cas locus. Strains were then transformed with a plasmid expressing an inducible transcript with a target (pTarget, upper gels) or non-target (pControl, lower gels) sequence. Cultures were induced with anhydrotetracycline and samples were collected at the indicated time points. Plasmids were extracted, linearized by restriction digestion, separated and visualized with agarose gel electrophoresis. Performed once. “M”, molecular weight marker. (b) Calculation of the mutation rate of the data presented in Figure 3b. The bar graphs represent the mean; the error bars represent 95% confidence intervals. (c) Calculation of the mutation rate of S. epidermidis RP62a, wild-type and ΔCRISPR mutant. The bar graphs represent the mean; the error bars represent 95% confidence intervals; n=10 biologically independent experiments.