Localization of HArep-containing genes on the chromosome of Porphyromonas gingivalis W83

We have mapped a group of virulence genes of Porphyromonas gingivalis to a single large fragment of the genome. These genes (rgpA, kgp, and hagA) all contain a consensus repeat sequence (HArep). rgpA and kgp encode cysteine p roteases with Arg-X and Lys-X specificity, respectively, and hagA encodes a hemagglutinin, Genomic DNA fragments separated by pulse-field gel electrop horesis were blotted and probed in order to localize the genes to a 0.25-Mb NheI fragment of the P. gingivalis W83 genome, Further hybridization analy ses with single-and double-restriction digestion allowed us to generate a p hysical map of the fragment and determine the precise locations of the prot ease and hemagglutinin genes, In addition, we found an insertion-like seque nce, IS195, near the ends of the 0.25-Mb NheI fragment. A similarly sized f ragment carrying HArep sequences was also demonstrated in the P. gingivalis W12 and W50 genomes.