title: Characterization of the Aspergillus nidulans transporters for the siderophores enterobactin and triacetylfusarinine C.
abstract: The filamentous ascomycete Aspergillus nidulans produces three major siderophores: fusigen, triacetylfusarinine C, and ferricrocin. Biosynthesis and uptake of iron from these siderophores, as well as from various heterologous siderophores, is repressed by iron and this regulation is mediated in part by the transcriptional repressor SREA. Recently we have characterized a putative siderophore-transporter-encoding gene ( mirA ). Here we present the characterization of two further SREA- and iron-regulated paralogues (mirB and mirC ), including the chromosomal localization and the complete exon/intron structure. Expression of mirA and mirB in a Saccharomyces cerevisiae strain, which lacks high affinity iron transport systems, showed that MIRA transports specifically the heterologous siderophore enterobactin and that MIRB transports exclusively the native siderophore triacetylfusarinine C. Construction and analysis of an A. nidulans mirA deletion mutant confirmed the substrate specificity of MIRA. Phylogenetic analysis of the available sequences suggests that the split of the species A. nidulans and S. cerevisiae predates the divergence of the paralogous Aspergillus siderophore transporters.
authors.affiliation: Department of Molecular Biology, University of Innsbruck, Austria. hubertus.haas@uibk.ac.at
authors.forename: Hubertus
authors.initials: H
authors.lastname: Haas
authors.forename: Michelle
authors.initials: M
authors.lastname: Schoeser
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Lesuisse
authors.forename: Joachim F
authors.initials: JF
authors.lastname: Ernst
authors.forename: Walther
authors.initials: W
authors.lastname: Parson
authors.forename: Beate
authors.initials: B
authors.lastname: Abt
authors.forename: Günther
authors.initials: G
authors.lastname: Winkelmann
authors.forename: Harald
authors.initials: H
authors.lastname: Oberegger
mesh_terms: D000595:Amino Acid Sequence; D001233:Aspergillus nidulans / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D016384:Consensus Sequence; D017931:DNA Primers; D004758:Enterobactin / Q000378:metabolism*; D005091:Exons; D007438:Introns; D007501:Iron / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000378:metabolism; D008969:Molecular Sequence Data; D010802:Phylogeny; D010957:Plasmids; D016133:Polymerase Chain Reaction; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D016415:Sequence Alignment; D017262:Siderophores / Q000378:metabolism*
chemical_list: C409889:ARN2 protein, S cerevisiae; D001425:Bacterial Outer Membrane Proteins; D002352:Carrier Proteins; D017931:DNA Primers; D026901:Membrane Transport Proteins; D011956:Receptors, Cell Surface; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; D017262:Siderophores; C035902:siderophore receptors; D004758:Enterobactin; D007501:Iron