Regulation of gene expression in industrial fungi: Trichoderma

Mach, Robert L.; Zeilinger, Susanne

doi:10.1007/s00253-002-1162-x

Cited by 171 publications

(86 citation statements)

References 34 publications

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“…Wide-domain carbon catabolite repression has been shown to control the expression of both cellulase and hemicellulase genes in the presence of glucose (Ilmén et al, 1996(Ilmén et al, , 1997MargollesClark et al, 1997;Strauss et al, 1995;Takashima et al, 1996). Many of the transcription factors involved in regulation of the genes, CREI mediating carbon catabolite repression, the repressor ACEI, the activator ACEII, and the CCAAT binding complex Hap2/3/5, have been characterized in molecular detail (reviewed by Kubicek & Penttilä, 1998;Mach & Zeilinger, 2003;Schmoll & Kubicek, 2003).…”

Section: Introductionmentioning

confidence: 99%

The effect of specific growth rate on protein synthesis and secretion in the filamentous fungus Trichoderma reesei

et al. 2005

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Trichoderma reesei was cultivated in chemostat cultures on lactose-containing medium. The cultures were characterized for growth, consumption of the carbon source and protein production. Secreted proteins were produced most efficiently at low specific growth rates, 0?022-0?033 h "1 , the highest specific rate of total protein production being 4?1 mg g "1 h "1 at the specific growth rate 0?031 h "1. At low specific growth rates, up to 29 % of the proteins produced were extracellular, in comparison to only 6-8 % at high specific growth rates, 0?045-0?066 h "1 . To analyse protein synthesis and secretion in more detail, metabolic labelling of proteins was applied to analyse production of the major secreted protein, cellobiohydrolase I (CBHI, Cel7A). Intracellular and extracellular labelled CBHI was quantified and analysed for pI isoforms in two-dimensional gels, and the synthesis and secretion rates of the molecule were determined. Both the specific rates of CBHI synthesis and secretion were highest at low specific growth rates, the optimum being at 0?031 h "1 . However, at low specific growth rates the secretion rate/synthesis rate ratio was significantly lower than that at high specific growth rates, indicating that at low growth rates the capacity of cells to transport the protein becomes limiting. In accordance with the high level of protein production and limitation in the secretory capacity, the transcript levels of the unfolded protein response (UPR) target genes pdi1 and bip1 as well as the gene encoding the UPR transcription factor hac1 were induced.

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Section: Introductionmentioning

confidence: 99%

The effect of specific growth rate on protein synthesis and secretion in the filamentous fungus Trichoderma reesei

et al. 2005

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“…These small molecules are transported into the microorganism and start a massive expression of the degrading pectinases (Mach and Zeilinger, 2003). This would mean that several pectinolytic activities are induced by a number of substrates (Prade et al 1999).…”

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confidence: 99%

Kinetic study on inducibility of polygalacturonases from Aspergillus flavipes FP-500

Martínez-Trujillo¹,

Aranda²,

Aguilar-Osorio³

2008

Electron. J. Biotechnol.

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The aim of this work was to describe growth dynamics, substrate depletion and polygalacturonases production by Aspergillus flavipes FP-500 in batch cultures by means of unstructured models. The microorganism was cultivated on several mono-di-and poly-saccharides, and then the culture development modeled with Monod and Leudeking-Piret equations. The kinetic parameters related to the models (µ max , γ x/s , α and β) were obtained by minimizing the quadratic residuals function with a simplex algorithm. An accurate description of experimental data was attained with the proposed models. Besides, modeling provided significant kinetic information on microbial degradation of complex substrates, such as the correlation between specific growth rate µ max and production yield α, suggesting that A. flavipes FP-500 polygalacturonases are actually constitutive, but also that there is a certain degree of induciblility in these enzymatic activities.

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“…In addition, the xynB gene and major cellulase genes, such as cbpA-exgS and engE, were constitutively expressed (19)(20)(21). On the basis of a general model for induction of xylanase expression in Trichoderma reesei, a sensor enzyme may be constitutively expressed; this enzyme hydrolyzes xylan into oligosaccharides that can enter the bacterium and activates the expression of all the xylanase genes (33,57). It is possible that one or more of the constitutively expressed C. cellulovorans xylanases functions as the sensor enzyme.…”

Section: Resultsmentioning

confidence: 99%

Isolation and Expression of the xynB Gene and Its Product, XynB, a Consistent Component of the Clostridium cellulovorans Cellulosome

et al. 2004

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The nucleotide sequence of the Clostridium cellulovorans xynB gene, which encodes the XynB xylanase, consists of 1,821 bp and encodes a protein of 607 amino acids with a molecular weight of 65,976. XynB contains a typical N-terminal signal peptide of 29 amino acid residues, followed by a 147-amino-acid sequence that is homologous to the family 4-9 (subfamily 9 in family 4) carbohydrate-binding domain. Downstream of this domain is a family 10 catalytic domain of glycosyl hydrolase. The C terminus separated from the catalytic domain by a short linker sequence contains a dockerin domain responsible for cellulosome assembly. The XynB sequence from mass spectrometry and N-terminal amino acid sequence analyses agreed with that deduced from the nucleotide sequence. XynB was highly active toward xylan, but not active toward carboxymethyl cellulose. The enzyme was optimally active at 40°C and pH 5.0. Northern hybridizations revealed that xynB is transcribed as a monocistronic 1.9-kb mRNA. RNA ligase-mediated rapid amplification of 5 cDNA ends by PCR (RLM-5RACE PCR) analysis of C. cellulovorans RNA identified a single transcriptional start site of xynB located 47 bp upstream from the first nucleotide of the translation initiation codon. Alignment of the xynB promoter region provided evidence for highly conserved sequences that exhibited strong similarity to the A consensus promoter sequences of gram-positive bacteria. Expression of xynB mRNA increased from early to middle exponential phase and decreased during the early stationary phase when the cells were grown on cellobiose. No alternative promoter was observed by RLM-5RACE PCR and reverse transcriptase PCR analyses during expression. The analysis of the products from xylan hydrolysis by thin-layer chromatography indicated its endoxylanase activity. The results suggest that XynB is a consistent and major cellulosomal enzyme during growth on cellulose or xylan.Hemicellulose is the second most abundant renewable polysaccharide in nature after cellulose (3). ␤-1,4-Xylan is a major component of hemicellulose and has a backbone of ␤-1,4-linked D-xylopyranoside residues replaced by acetyl, arabinosyl, and uronyl side chains (50). The complete breakdown of xylan requires the action of several hydrolytic enzymes (3). The most important hydrolytic enzyme is endoxylanase (1,4-␤-Dxylan xylanohydrolase) (EC 3.2.1.8). Xylanases have been widely detected in bacteria and fungi, and their properties have been characterized (3,52). On the basis of the amino acid sequences of catalytic domains, xylanases have been classified into two groups: family 10 and family 11 of glycosyl hydrolases (25).Clostridium cellulovorans ATCC 35296 (44) produces a highly active polysaccharolytic complex termed the cellulosome, in which several cellulases are tightly bound to a scaffolding protein called CbpA (1). Doi et al. (11) and Tamaru et al. (11,49) have characterized the genes necessary for degradation of the plant cell wall of this bacterium. However, until now, only one xylanase gene, xynA, encodin...

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Regulation of gene expression in industrial fungi: Trichoderma

Cited by 171 publications

References 34 publications

The effect of specific growth rate on protein synthesis and secretion in the filamentous fungus Trichoderma reesei

The effect of specific growth rate on protein synthesis and secretion in the filamentous fungus Trichoderma reesei

Kinetic study on inducibility of polygalacturonases from Aspergillus flavipes FP-500

Isolation and Expression of the xynB Gene and Its Product, XynB, a Consistent Component of the Clostridium cellulovorans Cellulosome

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