fecB, a gene potentially involved in iron transport in Mycobacterium avium, is not induced within macrophages.
FecB is a protein involved in the transport of iron from ferric citrate in Escherichia coli and is present in the Mycobacterium tuberculosis genome sequence. Since the ability to retrieve iron from the host is crucial and may be related to virulence, we characterized the gene fecB from Mycobacterium avium, strain 101. An E. coli-mycobacterial shuttle plasmid with a fecB-promoter green fluorescence protein (gfp)-fusion was transformed into M. avium strain 104 to study the fecB-regulation. In vitro, the fecB expression in M. avium weakly correlated with the amount of iron present in the medium but the expression was maximal when there was no iron in the culture medium. In macrophages, M. avium fec B was not induced during the early phase of infection, suggesting that the iron concentration in the mycobacterial phagosome is not sufficiently low to stimulate the expression of fecB in M. avium.
Wagner
Dirk
D
Division of Infectious Diseases, Department of Internal Medicine II, University of Freiburg, Hugstetter Strasse 55, D-79106 Freiburg, Germany. dirk.wagner@medezin.ukl.uni-freiburg.de
Sangari
Felix J
FJ
Parker
Amy
A
Bermudez
Luiz E
LE
D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics*; D002460:Cell Line; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D050939:Gene Fusion; D017930:Genes, Reporter; D005822:Genetic Vectors / Q000235:genetics; D049452:Green Fluorescent Proteins / Q000032:analysis / Q000235:genetics; D016623:Ion Pumps / Q000235:genetics*; D008264:Macrophages / Q000382:microbiology*; D051379:Mice; D008969:Molecular Sequence Data; D015269:Mycobacterium avium Complex / Q000235:genetics*; D010588:Phagosomes / Q000382:microbiology*; D017422:Sequence Analysis, DNA
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D016623:Ion Pumps; D049452:Green Fluorescent Proteins