The basal level of transcription of the <i>alc</i> genes in the ethanol regulon in <i>Aspergillus nidulans</i> is controlled both by the specific transactivator AlcR and the general carbon catabolite repressor CreA

doi:10.1016/0014-5793(95)00736-s

Cited by 35 publications

(10 citation statements)

References 26 publications

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“…This phenomenon is known as carbon catabolite repression (CCR) and prevents the utilization of complex carbon sources, thereby allowing the fungus to select the energetically most favorable carbon source ( 61 , 62 ). In the reference organism A. nidulans , CCR is mediated by the transcriptional regulator CreA- and CreA-mediated repression of target genes and has been thoroughly investigated ( 63 – 65 ). For the present study, we set out to identify and characterize the potential F-box proteins involved in glucose utilization and CCR with the aim of identifying new regulatory mechanisms which could prove useful for biotechnological applications.…”

Section: Discussionmentioning

confidence: 99%

Regulation of Aspergillus nidulans CreA-Mediated Catabolite Repression by the F-Box Proteins Fbx23 and Fbx47

Assis

Ulas

Ries

et al. 2018

mBio

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The attachment of one or more ubiquitin molecules by SCF (Skp–Cullin–F-box) complexes to protein substrates targets them for subsequent degradation by the 26S proteasome, allowing the control of numerous cellular processes. Glucose-mediated signaling and subsequent carbon catabolite repression (CCR) are processes relying on the functional regulation of target proteins, ultimately controlling the utilization of this carbon source. In the filamentous fungus Aspergillus nidulans, CCR is mediated by the transcription factor CreA, which modulates the expression of genes encoding biotechnologically relevant enzymes. Although CreA-mediated repression of target genes has been extensively studied, less is known about the regulatory pathways governing CCR and this work aimed at further unravelling these events. The Fbx23 F-box protein was identified as being involved in CCR and the Δfbx23 mutant presented impaired xylanase production under repressing (glucose) and derepressing (xylan) conditions. Mass spectrometry showed that Fbx23 is part of an SCF ubiquitin ligase complex that is bridged via the GskA protein kinase to the CreA-SsnF-RcoA repressor complex, resulting in the degradation of the latter under derepressing conditions. Upon the addition of glucose, CreA dissociates from the ubiquitin ligase complex and is transported into the nucleus. Furthermore, casein kinase is important for CreA function during glucose signaling, although the exact role of phosphorylation in CCR remains to be determined. In summary, this study unraveled novel mechanistic details underlying CreA-mediated CCR and provided a solid basis for studying additional factors involved in carbon source utilization which could prove useful for biotechnological applications.

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Section: Discussionmentioning

confidence: 99%

Regulation of Aspergillus nidulans CreA-Mediated Catabolite Repression by the F-Box Proteins Fbx23 and Fbx47

Assis

Ulas

Ries

et al. 2018

mBio

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“…For example in A. nidulans , the genes of the ethanol regulon comprise the transacting regulatory gene alcR [20] and at least two main structural genes alcA (alcohol dehydrogenase I) [21] and aldA (aldehyde dehydrogenase) [22]. CreA directly represses the transcription of alcR as well as repressing alcA and aldA by competing with AlcR binding to promoter sequences [16], [18], [23]. Similarly, CreA also represses the xylanolytic system via direct repression of the pathway specific regulator, xlnR and both direct and indirect regulation of the structural gene xlnA [17], [19], [24].…”

Section: Introductionmentioning

confidence: 99%

Identification of the CRE-1 Cellulolytic Regulon in Neurospora crassa

2011

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BackgroundIn filamentous ascomycete fungi, the utilization of alternate carbon sources is influenced by the zinc finger transcription factor CreA/CRE-1, which encodes a carbon catabolite repressor protein homologous to Mig1 from Saccharomyces cerevisiae. In Neurospora crassa, deletion of cre-1 results in increased secretion of amylase and β-galactosidase.Methodology/Principal FindingsHere we show that a strain carrying a deletion of cre-1 has increased cellulolytic activity and increased expression of cellulolytic genes during growth on crystalline cellulose (Avicel). Constitutive expression of cre-1 complements the phenotype of a N. crassa Δcre-1 strain grown on Avicel, and also results in stronger repression of cellulolytic protein secretion and enzyme activity. We determined the CRE-1 regulon by investigating the secretome and transcriptome of a Δcre-1 strain as compared to wild type when grown on Avicel versus minimal medium. Chromatin immunoprecipitation-PCR of putative target genes showed that CRE-1 binds to only some adjacent 5′-SYGGRG-3′ motifs, consistent with previous findings in other fungi, and suggests that unidentified additional regulatory factors affect CRE-1 binding to promoter regions. Characterization of 30 mutants containing deletions in genes whose expression level increased in a Δcre-1 strain under cellulolytic conditions identified novel genes that affect cellulase activity and protein secretion.Conclusions/SignificanceOur data provide comprehensive information on the CRE-1 regulon in N. crassa and contribute to deciphering the global role of carbon catabolite repression in filamentous ascomycete fungi during plant cell wall deconstruction.

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“…1999) were all repressed by ammonium ; alcR, alcA (Fillinger et al . 1995) , acuG (Hynes et al . 2007) , xlnD (Tamayo et al .…”

Section: Resultsmentioning

confidence: 99%

The role of the GATA transcription factor AreB in regulation of nitrogen and carbon metabolism in Aspergillus nidulans

Chudzicka-Ormaniec

Macios

Koper

et al. 2019

FEMS Microbiology Letters

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In Aspergillus nidulans , nitrogen and carbon metabolism are under the control of wide-domain regulatory systems, including nitrogen metabolite repression, carbon catabolite repression and the nutrient starvation response. Transcriptomic analysis of the wild type strain grown under different combinations of carbon and nitrogen regimes was performed, to identify differentially regulated genes. Carbon metabolism predominates as the most important regulatory signal but for many genes, both carbon and nitrogen metabolisms coordinate regulation. To identify mechanisms coordinating nitrogen and carbon metabolism, we tested the role of AreB, previously identified as a regulator of genes involved in nitrogen metabolism. Deletion of areB has significant phenotypic effects on the utilization of specific carbon sources, confirming its role in the regulation of carbon metabolism. AreB was shown to regulate the expression of areA , tamA, creA, xprG and cpcA regulatory genes suggesting areB has a range of indirect, regulatory effects. Different isoforms of AreB are produced as a result of differential splicing and use of two promoters which are differentially regulated by carbon and nitrogen conditions. These isoforms are likely to be functionally distinct and thus contributing to the modulation of AreB activity.

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The basal level of transcription of the alc genes in the ethanol regulon in Aspergillus nidulans is controlled both by the specific transactivator AlcR and the general carbon catabolite repressor CreA

Cited by 35 publications

References 26 publications

Regulation of Aspergillus nidulans CreA-Mediated Catabolite Repression by the F-Box Proteins Fbx23 and Fbx47

Regulation of Aspergillus nidulans CreA-Mediated Catabolite Repression by the F-Box Proteins Fbx23 and Fbx47

Identification of the CRE-1 Cellulolytic Regulon in Neurospora crassa

The role of the GATA transcription factor AreB in regulation of nitrogen and carbon metabolism in Aspergillus nidulans

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