title: In vivo expression of UDP-N-acetylglucosamine: Alpha-3-D-mannoside beta-1,2-N-acetylglucosaminyltransferase I (GnT-1) in Aspergillus oryzae and effects on the sugar chain of alpha-amylase.
abstract: UDP-N-Acetylglucosamine: alpha-3-D-mannoside beta-1,2-N-acetylglucosaminyltransferase I (GnT-I) is an essential enzyme in the conversion of high mannose type oligosaccharide to the hybrid or complex type. The full length of the rat GnT-I gene was expressed in the filamentous fungus Aspergillus oryzae. A microsomal preparation from a recombinant fungus (strain NG) showed GnT-I activity that transferred N-acetylglucosamine residue to acceptor heptaose, Man(5)GlcNAc(2). The N-linked sugar chain of alpha-amylase secreted by the strain showed a peak of novel retention on high performance liquid chromatography that was same as a reaction product of in vitro GnT-1 assay. The peak of oligosaccharide disappeared on HPLC after beta-N-acetylglucosaminidase treatment. Mass analysis supported the presence of GlcNAcMan(5)GlcNAc(2) as a sugar chain of alpha-amylase from strain NG. Chimera of GnT-I with green fluorescent protein (GFP) showed a dotted pattern of fluorescence in the mycelia, suggesting localization at Golgi vesicles. We concluded that GnT-1 was functionally expressed in A. oryzae cells and that N-acetylglucosamine residue was transferred to N-glycan of alpha-amylase in vivo. A. oryzae is expected to be a potential host for the production of glycoprotein with a genetically altered sugar chain.
authors.affiliation: Laboratory of Cell Technology, Faculty of Agriculture and Life Science, Hirosaki University, Hirosaki, Aomori, Japan.
authors.forename: Yuya
authors.initials: Y
authors.lastname: Kasajima
authors.forename: Masako
authors.initials: M
authors.lastname: Yamaguchi
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Hirai
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Ohmachi
authors.forename: Takashi
authors.initials: T
authors.lastname: Yoshida
mesh_terms: D001236:Aspergillus oryzae / Q000201:enzymology* / Q000235:genetics; D050260:Carbohydrate Metabolism; D002241:Carbohydrates / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D015870:Gene Expression; D006031:Glycosylation; D008856:Microscopy, Fluorescence; D017351:N-Acetylglucosaminyltransferases / Q000235:genetics / Q000378:metabolism*; D010957:Plasmids / Q000235:genetics; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014537:Uridine Diphosphate N-Acetylglucosamine / Q000235:genetics / Q000378:metabolism*; D000516:alpha-Amylases / Q000378:metabolism*
chemical_list: D002241:Carbohydrates; D014537:Uridine Diphosphate N-Acetylglucosamine; D017351:N-Acetylglucosaminyltransferases; D000516:alpha-Amylases