TY - JOUR
T1 - Characterization and expression analysis of a maltose-utilizing (MAL) cluster in Aspergillus oryzae
AU - Hasegawa, Sachiko
AU - Takizawa, Masahiro
AU - Suyama, Haruhiko
AU - Shintani, Takahiro
AU - Gomi, Katsuya
N1 - Funding Information:
We are grateful to Dr. Corrine A. Michels, The City University of New York for generously providing the yeast mutant strains and critical reading of the manuscript. This work was supported by a Grant-in-Aid for Scientific Research on Priority Areas, Applied Genomics (No. 17019001 ) from the Ministry of Education, Culture, Sports, Science, and Technology of Japan.
PY - 2010/1
Y1 - 2010/1
N2 - Starch and maltooligosaccharides such as maltose and maltotriose induce the production of amylolytic enzymes including α-amylase in Aspergillus oryzae. A transcriptional activator gene amyR, required for maltose induction of amylolytic enzymes, has been cloned and characterized. The amyR gene deletion mutant showed significantly poor growth on starch medium but normal growth on maltose medium. This indicated the existence of another maltose-utilizing system, whose expression might not be controlled by amyR. We have identified a gene cluster homologous to the MAL cluster of Saccharomyces cerevisiae in the A. oryzae genome. The cluster consists of a MAL61 homolog (designated malP), a MAL62 homolog (designated malT), and a MAL63 homolog (designated malR). Overexpression of malT in A. oryzae resulted in a significant increase in intracellular α-glucosidase activity, and that of malP allowed S. cerevisiae mal61Δ to grow on maltose. The expression of both malP and malT genes was highly up-regulated in the presence of maltose, but malR expressed constitutively irrespective of carbon sources. Disruption of malR resulted in the loss of malP and malT expression and thus in restricted growth on maltose medium. In addition, a malP disruptant showed a significantly reduced expression of malT and malR and exhibited a growth defect on maltose similar to the malR disruptant. These results suggest that the MAL cluster of A. oryzae is responsible for the assimilation of maltose in A. oryzae.
AB - Starch and maltooligosaccharides such as maltose and maltotriose induce the production of amylolytic enzymes including α-amylase in Aspergillus oryzae. A transcriptional activator gene amyR, required for maltose induction of amylolytic enzymes, has been cloned and characterized. The amyR gene deletion mutant showed significantly poor growth on starch medium but normal growth on maltose medium. This indicated the existence of another maltose-utilizing system, whose expression might not be controlled by amyR. We have identified a gene cluster homologous to the MAL cluster of Saccharomyces cerevisiae in the A. oryzae genome. The cluster consists of a MAL61 homolog (designated malP), a MAL62 homolog (designated malT), and a MAL63 homolog (designated malR). Overexpression of malT in A. oryzae resulted in a significant increase in intracellular α-glucosidase activity, and that of malP allowed S. cerevisiae mal61Δ to grow on maltose. The expression of both malP and malT genes was highly up-regulated in the presence of maltose, but malR expressed constitutively irrespective of carbon sources. Disruption of malR resulted in the loss of malP and malT expression and thus in restricted growth on maltose medium. In addition, a malP disruptant showed a significantly reduced expression of malT and malR and exhibited a growth defect on maltose similar to the malR disruptant. These results suggest that the MAL cluster of A. oryzae is responsible for the assimilation of maltose in A. oryzae.
KW - Aspergillus oryzae
KW - Gene cluster
KW - Gene expression
KW - Maltose permease
KW - Maltose utilization
KW - Transcription factor
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U2 - 10.1016/j.fgb.2009.10.005
DO - 10.1016/j.fgb.2009.10.005
M3 - Article
C2 - 19850146
AN - SCOPUS:71249102526
VL - 47
SP - 1
EP - 9
JO - Fungal Genetics and Biology
JF - Fungal Genetics and Biology
SN - 1087-1845
IS - 1
ER -