Figure 3

Overview of CRISPR (clustered regularly interspaced short palindromic repeats) loci in L monocytogenes 1/2a EGD-e, L. monocytogenes 4a L99, L. monocytogenes 4a HCC23, L. monocytogenes 4a M7, L. monocytogenes 4c FSL J2-071, L. monocytogenes 4b CLIP80459, L. monocytogenes 4b F2365 and L. innocua 6a CLIP11262. (A): CRISPR locus I is shown for all five listeriae, black boxes indicate complete CRISPR repeats, red boxes represent incomplete or truncated (*) CRISPR repeats. No cas genes were found to be associated with this locus. Flanking genes are conserved in 1/2a EGD-e and both 4b genomes. Comparison of the intergenic sequences with the 4a L99 genome revealed a sequence footprint of decaying repeat elements (2 repeat copies in both 4b genomes, and 1 copy in L. innocua 6a CLIP11262), indicating loss of the CRISPR repeats. (B): Locus II shows 29 copies of repeats and is associated with several cas genes (cas2, cas3, cas5 and cas6. cas1 is partially detectable, but seems to be truncated. (C): L. innocua 6a CLIP11262 harbours the CRISPR locus III at position 2.77 Mb in the genome, which is neighboured by a single cas2 gene. No other CRISPR repeats nor any cas gene homologs were found in the 4b genomes.