Regulation of hemin and iron transport in Porphyromonas gingivalis.
As with other pathogens, a requirement for the in vivo growth of Porphyromonas gingivalis is that the organism must be capable of obtaining iron from the host. The ability to utilize hemin and hemin-containing compounds for nutritional iron has been documented for several pathogenic bacteria, including P. gingivalis; however, the mechanisms involved in hemin uptake are poorly defined. I have determined that P. gingivalis transports the entire hemin moiety into the cell by an energy-dependent mechanism and that the binding and accumulation of hemin are induced by growth of cultures in the presence of hemin. A model of hemin transport in P. gingivalis consistent with these results is presented. I have also found that, in P. gingivalis, hemin regulates the expression of several putative virulence factors; this in turn results in the increased virulence potential of P. gingivalis as assessed in an animal model. Regulation of hemin-responsive genes in P. gingivalis may occur by a negative regulator, as has been described in other pathogenic organisms.
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Department of Microbiology and Immunology, Morehouse School of Medicine, Atlanta, Georgia 30310-1495, USA.
D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism; D001483:Base Sequence; D001693:Biological Transport, Active; D017931:DNA Primers; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D006427:Hemin / Q000378:metabolism*; D007501:Iron / Q000378:metabolism*; D008969:Molecular Sequence Data; D016966:Porphyromonas gingivalis / Q000235:genetics* / Q000378:metabolism* / Q000472:pathogenicity; D014774:Virulence
D001425:Bacterial Outer Membrane Proteins; D017931:DNA Primers; D006427:Hemin; D007501:Iron