title: Contribution ratios of amyA, amyB, amyC genes to high-level α-amylase expression in Aspergillus oryzae.
abstract: Aspergillus oryzae strains express α-amylases abundantly, and the genome reference strain RIB40 has three α-amylase genes (amyA, amyB, and amyC). However, there is no information on the contribution ratios of individual α-amylase genes to total expression. In this study, we generated single, double, and triple disruptants of α-amylase genes by employing a strain (ΔligD) with high gene-targeting efficiency and pyrG marker recycling in A. oryzae. All the disruptants showed reduced activities of α-amylases, and the triple disruptant completely lost activity. Comparative analyses of the activities and mRNA amounts of the α-amylases suggest that the contribution of amyA to the α-amylase expression is smaller than those of amyB and amyC. The present study suggests that the ability to express a large amount of α-amylases in A. oryzae is attributed to gene duplication of genes such as amyB and amyC.
authors.affiliation: Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Tokyo 113-8657, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Nemoto
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Maruyama
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Kitamoto
mesh_terms: D001236:Aspergillus oryzae / Q000201:enzymology / Q000235:genetics*; D001483:Base Sequence; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D017353:Gene Deletion; D020440:Gene Duplication; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D005818:Genetic Engineering; D008969:Molecular Sequence Data; D005810:Multigene Family; D000516:alpha-Amylases / Q000235:genetics* / Q000378:metabolism
chemical_list: D005656:Fungal Proteins; D000516:alpha-Amylases