title: The beta-1,3-exoglucanase gene exgA (exg1) of Aspergillus oryzae is required to catabolize extracellular glucan, and is induced in growth on a solid surface.
abstract: The biological role of ExgA (Exg1), a secretory beta-1,3-exoglucanase of Aspergillus oryzae, and the expression pattern of the exgA (exg1) gene were analyzed. The exgA disruptant and the exgA-overexpressing mutant were constructed, and phenotypes of both mutants were compared. Higher mycelial growth rate and conidiation efficiency were observed for the exgA-overexpressing mutant than for the exgA disruptant when beta-1,3-glucan was supplied as sole carbon source. On the other hand, no difference in phenotype was observed between them in the presence or absence of the inhibitors of cell wall beta-glucan remodeling when grown with glucose. exgA Expression was induced in growth on solid surfaces such as filter membrane and onion inner skin. A combination of poor nutrition and mycelial attachment to a hydrophobic solid surface appears to be an inducing factor for exgA expression. These data suggest that ExgA plays a role in beta-glucan utilization, but is not much involved in cell wall beta-glucan remodeling.
authors.affiliation: Research Institute for Cell Engineering, National Institute of Advanced Industrial Science and Technology, Ibaraki, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Tamano
authors.forename: Yuki
authors.initials: Y
authors.lastname: Satoh
authors.forename: Tomoko
authors.initials: T
authors.lastname: Ishii
authors.forename: Yasunobu
authors.initials: Y
authors.lastname: Terabayashi
authors.forename: Shinsaku
authors.initials: S
authors.lastname: Ohtaki
authors.forename: Motoaki
authors.initials: M
authors.lastname: Sano
authors.forename: Tadashi
authors.initials: T
authors.lastname: Takahashi
authors.forename: Yasuji
authors.initials: Y
authors.lastname: Koyama
authors.forename: Osamu
authors.initials: O
authors.lastname: Mizutani
authors.forename: Keietsu
authors.initials: K
authors.lastname: Abe
authors.forename: Masayuki
authors.initials: M
authors.lastname: Machida
mesh_terms: D001236:Aspergillus oryzae / Q000201:enzymology* / Q000235:genetics* / Q000254:growth & development; D002473:Cell Wall / Q000737:chemistry / Q000648:ultrastructure; D003470:Culture Media; D018076:DNA, Complementary / Q000096:biosynthesis / Q000235:genetics; D004271:DNA, Fungal / Q000235:genetics; D005374:Filtration; D015971:Gene Expression Regulation, Enzymologic / Q000235:genetics / Q000502:physiology; D015966:Gene Expression Regulation, Fungal / Q000235:genetics / Q000502:physiology; D043326:Glucan 1,3-beta-Glucosidase / Q000235:genetics*; D005936:Glucans / Q000378:metabolism*; D025282:Mycelium / Q000201:enzymology / Q000254:growth & development; D009747:Nutritional Physiological Phenomena; D019697:Onions / Q000382:microbiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013499:Surface Properties; D014170:Transformation, Genetic
chemical_list: D003470:Culture Media; D018076:DNA, Complementary; D004271:DNA, Fungal; D005936:Glucans; D043326:Glucan 1,3-beta-Glucosidase; C117648:beta-1,3-exoglucanase