Identification of functional elements that regulate the glucoamylase-encoding gene (glaB) expressed in solid-state culture of Aspergillus oryzae.
Aspergillus oryzae has-two glucoamylase-encoding genes, glaA and glaB, whose expressions are distinguished by the type of culture used. The glaB gene is markedly expressed in solid-state culture but is little expressed in submerged culture. In solid-state culture, glaB expression at the transcriptional level is enhanced by low-Aw (water activity), high-temperature, and physical barriers to hyphal extension, as well as by starch. To determine the cis-acting factors in the glaB promoter, deletion analysis of the promoter was done with GUS (beta-glucuronidase) as the reporter. Deletion of the 27 bp from -350 to -324 (Region A) in 1.1 kb of the glaB promoter completely abolished starch, low-Aw, and high-temperature induction. Substitution of the 12-bp GC-rich motif from -335 to -324 (GC-box) resulted in significant loss of starch and low-Aw inductivities. These findings suggest that the GC-box is a cis-element essential for the high-level expression of glaB in solid-state culture.
Ishida
H
H
Research Institute, Gekkeikan Sake Co. Ltd, Kyoto, Japan. h-ishida@gekkeikan.co.jp
Hata
Y
Y
Kawato
A
A
Abe
Y
Y
Suginami
K
K
Imayasu
S
S
D001236:Aspergillus oryzae / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D003470:Culture Media; D020862:GC Rich Sequence; D015966:Gene Expression Regulation, Fungal; D005087:Glucan 1,4-alpha-Glucosidase / Q000235:genetics* / Q000378:metabolism; D005966:Glucuronidase / Q000378:metabolism; D006358:Hot Temperature; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D017384:Sequence Deletion; D014867:Water
D003470:Culture Media; D014867:Water; D005087:Glucan 1,4-alpha-Glucosidase; D005966:Glucuronidase