Figure 2.
Schematic representation of the clustered regularly interspaced short palindromic repeats (CRISPRs) in S. Typhimurium DT4 (LT2), DT104, and DT104b. The eleven studied S. Typhimurium strains harbour two CRISPR loci, CRISPR-1 and CRISPR-2. The type I-E CRISPR/Cas system is encoded by an operon harbouring eight cas genes (blue boxed arrows) that are located upstream of CRISPR-1. Each CRISPR locus also contains a leader region (green horizontal lines). The black arrows show transcriptional orientation.