Transcriptional regulator of carbon catabolite repression CreA of filamentous fungus Penicillium canescens

The effect of carbon source on the levels of three (1 → 3)-β-glucanases and a (1 → 6)-β-glucanase in the culture filtrates of the filamentous fungus Acremonium persicinum was investigated. All four enzymes were produced during growth of the fungus on (1 → 3)-, (1 → 6)-, and (1 → 3)(1 → 6)-β-glucans as well as β-linked oligoglucosides. However, only one (1 → 3)-β-glucanase and the (1 → 6)-β-glucanase were detected during growth on a range of other carbon sources including glucose, carboxymethylcellulose, and the α-glucan pullulan. The presence of glucose in the medium markedly decreased the production of all four glucanases, although the concentration required to effect complete repression of enzyme levels varied for the different enzymes. Similar repressive effects were also observed with sucrose, fructose, and galactose. The most likely explanations for these observations are that the synthesis of the (1 → 6)-β-glucanase and one of the (1 → 3)-β-glucanases is controlled by carbon catabolite repression, while the remaining two (1 → 3)-β-glucanases are inducible enzymes subject to carbon catabolite repression.Key words: (1 → 3)-β-glucanase, (1 → 6)-β-glucanase, Acremonium persicinum, regulation of synthesis, fungal β-glucanases.

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Disruption of alpha-tubulin releases carbon catabolite repression and enhances enzyme production in Trichoderma reesei even in the presence of glucose

Biotechnology for Biofuels ◽

10.1186/s13068-021-01887-0 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Nozomu Shibata ◽

Hiroshi Kakeshita ◽

Kazuaki Igarashi ◽

Yasushi Takimura ◽

Yosuke Shida ◽

...

Keyword(s):

Trichoderma Reesei ◽

Catabolite Repression ◽

Enzyme Production ◽

Protein Production ◽

Carbon Catabolite Repression ◽

Transcriptional Regulator ◽

Secretory Protein ◽

Sugar Transporter ◽

Alpha Tubulin ◽

High Enzyme

Abstract Background Trichoderma reesei is a filamentous fungus that is important as an industrial producer of cellulases and hemicellulases due to its high secretion of these enzymes and outstanding performance in industrial fermenters. However, the reduction of enzyme production caused by carbon catabolite repression (CCR) has long been a problem. Disruption of a typical transcriptional regulator, Cre1, does not sufficiently suppress this reduction in the presence of glucose. Results We found that deletion of an α-tubulin (tubB) in T. reesei enhanced both the amount and rate of secretory protein production. Also, the tubulin-disrupted (ΔtubB) strain had high enzyme production and the same enzyme profile even if the strain was cultured in a glucose-containing medium. From transcriptome analysis, the ΔtubB strain exhibited upregulation of both cellulase and hemicellulase genes including some that were not originally induced by cellulose. Moreover, cellobiose transporter genes and the other sugar transporter genes were highly upregulated, and simultaneous uptake of glucose and cellobiose was also observed in the ΔtubB strain. These results suggested that the ΔtubB strain was released from CCR. Conclusion Trichoderma reesei α-tubulin is involved in the transcription of cellulase and hemicellulase genes, as well as in CCR. This is the first report of overcoming CCR by disrupting α-tubulin gene in T. reesei. The disruption of α-tubulin is a promising approach for creating next-generation enzyme-producing strains of T. reesei.

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Mutations in Catabolite Control Protein CcpA Separating Growth Effects from Catabolite Repression

Journal of Bacteriology ◽

10.1128/jb.181.13.4125-4128.1999 ◽

1999 ◽

Vol 181 (13) ◽

pp. 4125-4128 ◽

Cited By ~ 14

Author(s):

Elke Küster ◽

Tanja Hilbich ◽

Michael K. Dahl ◽

Wolfgang Hillen

Keyword(s):

Growth Rate ◽

Catabolite Repression ◽

Carbon Catabolite Repression ◽

Transcriptional Regulator ◽

Growth Effect ◽

Single Amino Acid ◽

Chromosomal Deletion ◽

Regulatory Pathways ◽

Amino Acid Mutations ◽

Control Protein

ABSTRACT Carbon catabolite repression in Bacillus megaterium is mediated by the transcriptional regulator CcpA. A chromosomal deletion of ccpA eliminates catabolite repression and reduces the growth rate on glucose. We describe four single-amino-acid mutations in CcpA which separate the growth effect from catabolite repression, suggesting distinct regulatory pathways for these phenotypes.

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