title: Differential physiological and developmental expression of the UapA and AzgA purine transporters in Aspergillus nidulans.
abstract: In this article we study the cellular expression of UapA and AzgA, the two major purine transporters of Aspergillus nidulans, by constructing strains expressing, from their native promoters, fully functional fluorescent (UapA-sGFP, AzgA-sGFP) or immunological (UapA-His) chimeric transporters. Epifluorescence microscopy and immunodetection showed that under different physiological conditions and during Aspergillus development: (i) UapA and AzgA expression in the plasma membrane becomes evident early during germination and remains at a significant basal level in mycelium, (ii) Neither of the two transporters is expressed in the stalk, the vesicle, the phialides and the conidiospores, but surprisingly, UapA is specifically and strongly expressed in the periphery of metulae, (iii) Both transporters are expressed in ascogenous hyphae and in hülle cells but not in cleistothecia or ascospores, (iv) Purine induction leads to approximately 4-fold increase in UapA and AzgA protein content in mycelium, compatible with an analogous increase at the transcriptional level, (v) Ammonium leads to removal of UapA, but not of AzgA, from the plasma membrane by sorting of the protein to the vacuole.
authors.affiliation: Faculty of Biology, Department of Botany, University of Athens, Panepistimioupolis, Athens 15781, Greece.
authors.forename: Areti
authors.initials: A
authors.lastname: Pantazopoulou
authors.forename: Njimoh Dieudonné
authors.initials: ND
authors.lastname: Lemuh
authors.forename: Dimitris G
authors.initials: DG
authors.lastname: Hatzinikolaou
authors.forename: Christine
authors.initials: C
authors.lastname: Drevet
authors.forename: Gianna
authors.initials: G
authors.lastname: Cecchetto
authors.forename: Claudio
authors.initials: C
authors.lastname: Scazzocchio
authors.forename: George
authors.initials: G
authors.lastname: Diallinas
mesh_terms: D000225:Adenine / Q000378:metabolism; D001233:Aspergillus nidulans / Q000254:growth & development / Q000378:metabolism*; D001692:Biological Transport; D002352:Carrier Proteins / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D003470:Culture Media; D015536:Down-Regulation; D005656:Fungal Proteins / Q000378:metabolism*; D006147:Guanine / Q000378:metabolism; D025301:Hyphae / Q000378:metabolism; D019271:Hypoxanthine / Q000378:metabolism; D015151:Immunoblotting; D026901:Membrane Transport Proteins / Q000378:metabolism; D011687:Purines / Q000378:metabolism*; D000644:Quaternary Ammonium Compounds
chemical_list: D002352:Carrier Proteins; D003470:Culture Media; D005656:Fungal Proteins; D026901:Membrane Transport Proteins; D011687:Purines; D000644:Quaternary Ammonium Compounds; C083852:UAPA protein, Aspergillus nidulans; D019271:Hypoxanthine; D006147:Guanine; D000225:Adenine; C030985:purine