Characteristic expression of three amylase-encoding genes, agdA, amyB, and glaA in aspergillus oryzae transformants containing multiple copies of the agda gene

Gakuzo Tamura, Toshitaka Minetoki, Chieko Kumaga, Katsuya Gomi, Katsuhiko Kitamoto, Chieko Kumaga, Katsuhiko Kitamoto

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)

Abstract

In Aspergillus oryzae wild-type strains, the expression of the agdA gene encoding α-glucosidase (AGL) is induced by maltose at the transcriptional level in a similar manner to the amyB gene encoding Taka-amylase A (TAA) and the glaA gene encoding glucoamylase (GLA). In A. oryzae transformants containing multiple copies of the agdA gene, a high-level of AGL activity was observed. This was accompanied by a significant reduction in TAA and GLA activities. Moreover, transformants with the highest AGL activity showed the lowest degree of TAA and GLA activities. Northern blot analyses showed that the transcriptional levels of amyB and glaA in the AGL-overproducing transformant were drastically reduced when large amounts of agdA mRNA were detected in maltose-grown mycelia. In addition, the glucose concentration of the maltose-containing medium that was used to grow the AGL-overproducing transformant for RNA extraction was higher than that of the control transformant. These results suggest that the reduced expression of the amyB and glaA genes in the AGL-overproducing transformant was due to either titration of a common regulatory protein(s) involved in maltose induction or carbon catabolite repression.

Original languageEnglish
Pages (from-to)2251-2254
Number of pages4
JournalBioscience, Biotechnology and Biochemistry
Volume59
Issue number12
DOIs
Publication statusPublished - 1995
Externally publishedYes

ASJC Scopus subject areas

  • Biotechnology
  • Analytical Chemistry
  • Biochemistry
  • Applied Microbiology and Biotechnology
  • Molecular Biology
  • Organic Chemistry

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