PORPHYROMONAS-GINGIVALIS GENES ISOLATED BY SCREENING FOR EPITHELIAL-CELL ATTACHMENT

Porphyromonas gingivalis is associated with chronic and severe periodo ntitis in adults. P, gingivalis and the other periodontal pathogens co lonize and interact with gingival epithelial cells, but the genes and molecular mechanisms involved are unknown. To dissect the first steps in these interactions, a P, gingivalis expression library was screened for clones which bound human oral epithelial cells, Insert DNA from t he recombinant clones did not contain homology to the P. gingivalis fi mA gene, encoding fimbrillin, the subunit protein of fimbriae, but sho wed various degrees of homology to certain cysteine protease-hemagglut inin genes. The DNA sequence of one insert revealed three putative ope n reading frames which appeared to be in an operon. The relationship b etween P, gingivalis attachment to epithelial cells and the activities identified by the screen is discussed.