title: Comparison and characterization of α-amylase inducers in Aspergillus nidulans based on nuclear localization of AmyR.
abstract: AmyR, a fungal transcriptional activator responsible for induction of amylolytic genes in Aspergillus nidulans, localizes to the nucleus in response to the physiological inducer isomaltose. Maltose, kojibiose, and D: -glucose were also found to trigger the nuclear localization of GFP-AmyR. Isomaltose- and kojibiose-triggered nuclear localization was not inhibited by the glucosidase inhibitor, castanospermine, while maltose-triggered localization was inhibited. Thus, maltose itself does not appear to be an direct inducer, but its degraded or transglycosylated product does. Non-metabolizable D: -glucose analogues were also able to trigger the nuclear localization, implying that these sugars, except maltose, directly function as the inducers of AmyR nuclear entry. The inducing activity of D: -glucose was 4 orders-of-magnitude weaker compared with isomaltose. Although D: -glucose has the ability to induce α-amylase production, this activity would generally be masked by CreA-dependent carbon catabolite repression. Significant induction of α-amylase by D: -glucose was observed in creA-defective A. nidulans.
authors.affiliation: Department of Biological Mechanisms and Functions, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Nagoya-shi, Aichi 464-8601, Japan.
authors.forename: Yuriko
authors.initials: Y
authors.lastname: Murakoshi
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Makita
authors.forename: Masashi
authors.initials: M
authors.lastname: Kato
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Kobayashi
mesh_terms: D001233:Aspergillus nidulans / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D002467:Cell Nucleus / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D004187:Disaccharides / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D015966:Gene Expression Regulation, Fungal; D005947:Glucose / Q000378:metabolism; D007534:Isomaltose / Q000378:metabolism; D008320:Maltose / Q000378:metabolism; D021381:Protein Transport; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation; D000516:alpha-Amylases / Q000235:genetics* / Q000378:metabolism
chemical_list: D004187:Disaccharides; D005656:Fungal Proteins; D015534:Trans-Activators; D007534:Isomaltose; D008320:Maltose; C008237:kojibiose; D000516:alpha-Amylases; D005947:Glucose