Adhesion properties of mutants of Staphylococcus aureus defective in fibronectin-binding proteins and studies on the expression of fnb genes.
Staphylococcus aureus 8325-4 has the potential to express two distinct cell wall-associated fibronectin-binding proteins called FnBPA and FnBPB. In order to test if both proteins are expressed in S. aureus and if both are required for promoting bacterial adhesion to fibronectin-coated surfaces, insertion mutations were isolated in each gene. A DNA fragment encoding tetracycline resistance was inserted into fnbA and a fragment encoding erythromycin resistance was inserted into fnbB. A double fnbAfnbB mutant was also constructed. The fnbA and fnbB single mutants showed no significant reduction in their adhesion to polymethylmethacrylate coverslips that had been coated in vitro with fibronectin. However, the double mutant was completely defective in adhesion. Monospecific antibodies directed against the non-conserved N-terminal regions of both proteins confirmed the lack of expression of FnBPs in the mutant strains. Wild-type fnbA and fnbB genes cloned seperately on a multicopy plasmid were each able to restore fully the adhesion-defective phenotype of the 8325-4 fnbAfnbB mutant. This demonstrates that both fnb genes are expressed in S. aureus and that both contribute to the ability of strain 8325-4 to adhere to fibronectin-coated surfaces. The double mutant was also defective in adhesion to coverslips that had been removed from tissue cages implanted subcutaneously in guinea-pigs, which suggests that fibronectin is important in promoting attachment of S. aureus to biomaterial in vivo.
Greene
C
C
Department of Microbiology, Moyne Institute of Preventive Medicine, Trinity College, Dublin, Ireland.
McDevitt
D
D
Francois
P
P
Vaudaux
P E
PE
Lew
D P
DP
Foster
T J
TJ
D018829:Adhesins, Bacterial; D000818:Animals; D001422:Bacterial Adhesion / Q000235:genetics; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D001426:Bacterial Proteins; D001483:Base Sequence; D002352:Carrier Proteins; D004926:Escherichia coli / Q000235:genetics; D005353:Fibronectins / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D018390:Gene Targeting; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D006168:Guinea Pigs; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D011401:Promoter Regions, Genetic; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D013211:Staphylococcus aureus / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology*; D014774:Virulence / Q000235:genetics
D018829:Adhesins, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D002352:Carrier Proteins; D005353:Fibronectins; D011993:Recombinant Fusion Proteins; C078635:fibronectin-binding proteins, bacterial