FIG 1.

(A) Locations of CRISPR arrays and cas genes in the P. gingivalis chromosome. Protein annotation and CRISPR array nomenclature are presented according to the system of Watanabe et al. (26). The name of each CRISPR contains the length of a single repeat (and a consecutive number, if there are other arrays with the same repeat length). Arrows indicate the predicted direction of gene transcription. Blocks representing overlapping sequences are shifted upwards. Regions of the genome not related to the CRISPR-Cas system are omitted. Positions of CRISPR regions in the genome are shown below the axis. (B) Scheme for analysis of the CRISPR arrays. Probes used in Northern blots are marked with thin arrows above and below the CRISPR arrays. The arrow at the end of a given CRISPR array indicates the determined direction of transcription. Self-targeting spacers are marked with bold frames.