CreA mediates repression of the regulatory gene xlnR which controls the production of xylanolytic enzymes in Aspergillus nidulans

Tamayo, Elsy N.; Villanueva, Alicia; Hasper, Alinda A.; Graaff, L.H. de; Ramón, Daniel; Orejas, Margarita

doi:10.1016/j.fgb.2008.03.002

Cited by 107 publications

(116 citation statements)

References 68 publications

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“…The C2H2 zinc finger transcription factor CreA/ CRE1/CRE-1 (26) plays a key role in CCR as strains lacking CreA/CRE1/CRE-1 in Aspergillus sp., T. reesei, and N. crassa, respectively, produce increased amounts of both cellulases and hemicellulases when grown on cellulose or hemicellulose (21,27,28). Consistent with previous data (21), quantitative RT-PCR analysis of RNA isolated from an N. crassa cre-1 deletion strain (ΔNCU08807) showed that the basal expression of cbh-1 and gh5-1 increased about 10-fold relative to a WT strain (Fig.…”

Section: Resultssupporting

confidence: 89%

Induction of lignocellulose-degrading enzymes in Neurospora crassa by cellodextrins

Znameroski¹,

Coradetti

Roche³

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

210

212

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Neurospora crassa colonizes burnt grasslands in the wild and metabolizes both cellulose and hemicellulose from plant cell walls. When switched from a favored carbon source such as sucrose to cellulose, N. crassa dramatically upregulates expression and secretion of a wide variety of genes encoding lignocellulolytic enzymes. However, the means by which N. crassa and other filamentous fungi sense the presence of cellulose in the environment remains unclear. Here, we show that an N. crassa mutant carrying deletions of two genes encoding extracellular β-glucosidase enzymes and one intracellular β-glucosidase lacks β-glucosidase activity, but efficiently induces cellulase gene expression in the presence of cellobiose, cellotriose, or cellotetraose as a sole carbon source. These data indicate that cellobiose, or a modified version of cellobiose, functions as an inducer of lignocellulolytic gene expression in N. crassa . Furthermore, the inclusion of a deletion of the catabolite repressor gene, cre-1 , in the triple β-glucosidase mutant resulted in a strain that produces higher concentrations of secreted active cellulases on cellobiose. Thus, the ability to induce cellulase gene expression using a common and soluble carbon source simplifies enzyme production and characterization, which could be applied to other cellulolytic filamentous fungi.

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Section: Resultssupporting

confidence: 89%

Induction of lignocellulose-degrading enzymes in Neurospora crassa by cellodextrins

Znameroski¹,

Coradetti

Roche³

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

210

212

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“…Analysis of its genome [15] in combination with proteomic studies [9,16] show it to have a similar polysaccharide degradation potential to that of the industrial fungi, and in addition the regulatory mechanisms involved in controlling the expression of plant cell wall degrading activities are mostly conserved between it and industrially important fungi [17][18][19][20]. Finally, the use of A. nidulans as a production vehicle could provoke less concern regarding mycotoxin synthesis since its genome encodes the metabolic pathway for the less toxic compound sterigmatocystin compared to certain industrial strains which still retain the capacity to produce very harmful mycotoxins [21,22].…”

Section: Introductionmentioning

confidence: 99%

“…In this context, we are exploring the potential of other regulated A. nidulans promoters, such as those of the xylanolytic genes xlnA (encodes xylanase X 22 ) and xlnB (encodes xylanase X 24 ), with the aim of obtaining improvements in expression levels and/or production times of both endogenous and heterologous high-value plant cell wall degrading enzymes. The biotic and abiotic factors influencing the expression of these promoters (xlnA p and xlnB p ) and the transcriptional repressors and activators associated with them have been thoroughly characterized [18,[25][26][27]]. An additional advantage of these alternative promoters is the almost complete lack of basal level of expression in the absence of the inducer.…”

Section: Introductionmentioning

confidence: 99%

“…The activities of the xlnA and xlnB promoters are tightly regulated by at least three mechanisms: ambient pH regulation mediated by the wide-domain transcriptional factor PacC, carbon catabolite repression (CCR) mediated by the wide-domain repressor CreA and specific induction in the presence of xylan or xylose controlled by the Zn(II) 2 Cys 6 protein XlnR, which is itself transcriptionally regulated by CreA [18,[25][26][27]. For efficient induction, xlnA p requires both xylose and alkaline pH whereas xlnB p requires xylose and acidic pH [25].…”

Section: Introductionmentioning

confidence: 99%

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Enhanced glycosyl hydrolase production in Aspergillus nidulans using transcription factor engineering approaches

Tamayo-Ramos

Orejas

2014

Biotechnol Biofuels

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Background: Engineered fungi are attractive platforms for the production of plant cell wall hydrolytic enzymes which, among other biotechnological applications, are required for the efficient conversion of biomass to glucose and other fermentable sugars. As a fungal model system, Aspergillus nidulans provides genetic tools that are of relevance in this context and potentially applicable to industrially important filamentous fungi. The goal of this study is to assess the utility of A. nidulans as a host for recombinant protein production.

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“…The binding sites for CreA/CRE1 are two neighbouring palindromic consensus sequences in the promoter of genes (5'-SYGGRG-3' in A. nidulans [73] and T. reesei [74]), and binding of CreA/CRE1 thus hinders their transcription. CreA/CRE1 is a master regulator insofar as CreA/CRE1 regulates other transcription factors such as activators of genes encoding CAZymes [51,75]. A CreA/CRE1 orthologue was found in the genomes of most of the 108 ascomycete and basidiomycete species analysed by Todd et al [76].…”

Section: Transcriptional Repressorsmentioning

confidence: 99%

Transcriptional Regulation and Responses in Filamentous Fungi Exposed to Lignocellulose

2015

Mycology: Current and Future Developments

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Biofuels derived from lignocellulose are attractive alternative fuels but their production suffers from a costly and inefficient saccharification step that uses fungal enzymes. One route to improve this efficiency is to understand better the transcriptional regulation and responses of filamentous fungi to lignocellulose. Sensing and initial contact of the fungus with lignocellulose is an important aspect. Differences and similarities in the responses of fungi to different lignocellulosic substrates can partly be explained with existing understanding of several key regulators and their mode of action, as will be demonstrated for Trichoderma reesei, Neurospora crassa and Aspergillus spp. The regulation of genes encoding Carbohydrate Active enZymes (CAZymes) is influenced by the presence of carbohydrate monomers and short oligosaccharides, as well as the external stimuli of pH and light. We explore several important aspects of the response to lignocellulose that are not related to genes encoding CAZymes, namely the regulation of transporters, accessory proteins and stress responses. The regulation of gene expression is examined from the perspective of mixed cultures and models are presented for the nature of the transcriptional basis for any beneficial effects of such mixed cultures. Various applications in biofuel technology are based on manipulating transcriptional regulation and learning from fungal responses to lignocelluloses. Here we critically access the application of fungal transcriptional responses to industrial saccharification reactions. As part of this chapter, selected regulatory mechanisms are also explored in more detail.

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CreA mediates repression of the regulatory gene xlnR which controls the production of xylanolytic enzymes in Aspergillus nidulans

Cited by 107 publications

References 68 publications

Induction of lignocellulose-degrading enzymes in Neurospora crassa by cellodextrins

Induction of lignocellulose-degrading enzymes in Neurospora crassa by cellodextrins

Enhanced glycosyl hydrolase production in Aspergillus nidulans using transcription factor engineering approaches

Transcriptional Regulation and Responses in Filamentous Fungi Exposed to Lignocellulose

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