The glucose repressor gene cre1 of Trichoderma: isolation and expression of a full-length and a truncated mutant form.
The cre1 genes of the filamentous fungi Trichoderma reesei and T. harzianum were isolated and characterized. The deduced CREI proteins are 46% identical to the product of the glucose repressor gene creA of Aspergillus nidulans, encoding a DNA-binding protein with zinc fingers of the C2H2 type. The cre1 promoters contain several sequence elements that are identical to the previously identified binding sites for A. nidulans CREA. Steady-state mRNA levels for cre1 of the T. reesei strain QM9414 varied depending on the carbon source, being low on glucose-containing media. These observations suggest that cre1 expression may be autoregulated. The T. reesei strain Rut-C30, a hyper-producer of cellulolytic enzymes, was found to express a truncated form of the cre1 gene (cre1-1) with an ORF corresponding to a protein of 95 amino acids with only one zinc finger. Unlike QM9414 the strain Rut-C30 produced cellulase mRNAs on glucose-containing medium and transformation of the full-length cre1 gene into this strain caused glucose repression of cbh1 expression, demonstrating that cre1 regulates cellulase expression.
Ilmén
M
M
VTT Biotechnology and Food Research, Espoo, Finland.
Thrane
C
C
Penttilä
M
M
D000595:Amino Acid Sequence; D001483:Base Sequence; D002244:Carbon / Q000378:metabolism; D002480:Cellulase / Q000096:biosynthesis / Q000235:genetics; D004268:DNA-Binding Proteins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics*; D005656:Fungal Proteins; D015966:Gene Expression Regulation, Fungal; D005947:Glucose / Q000378:metabolism; D006706:Homeostasis; D008969:Molecular Sequence Data; D009154:Mutation; D011401:Promoter Regions, Genetic; D012097:Repressor Proteins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics*; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014242:Trichoderma / Q000737:chemistry / Q000235:genetics*
D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D012097:Repressor Proteins; D002244:Carbon; D002480:Cellulase; D005947:Glucose