Sequence analysis of the Aspergillus nidulans pectate lyase pelA gene and evidence for binding of promoter regions to CREA, a regulator of carbon catabolite repression

1995 ◽  
Vol 27 (2) ◽  
pp. 142-149 ◽  
Author(s):  
Meng-Chen Ho ◽  
Michael P. Whitehead ◽  
Thomas E. Cleveland ◽  
Ralph A. Dean



mBio ◽  
2018 ◽  
Vol 9 (3) ◽  
Author(s):  
Leandro José de Assis ◽  
Mevlut Ulas ◽  
Laure Nicolas Annick Ries ◽  
Nadia Ali Mohamed El Ramli ◽  
Ozlem Sarikaya-Bayram ◽  
...  

ABSTRACTThe 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 fungusAspergillus 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 Δfbx23mutant 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.IMPORTANCEThe production of biofuels from plant biomass has gained interest in recent years as an environmentally friendly alternative to production from petroleum-based energy sources. Filamentous fungi, which naturally thrive on decaying plant matter, are of particular interest for this process due to their ability to secrete enzymes required for the deconstruction of lignocellulosic material. A major drawback in fungal hydrolytic enzyme production is the repression of the corresponding genes in the presence of glucose, a process known as carbon catabolite repression (CCR). This report provides previously unknown mechanistic insights into CCR through elucidating part of the protein-protein interaction regulatory system that governs the CreA transcriptional regulator in the reference organismAspergillus nidulansin the presence of glucose and the biotechnologically relevant plant polysaccharide xylan.





2001 ◽  
Vol 40 (6) ◽  
pp. 1311-1321 ◽  
Author(s):  
Robin A. Lockington ◽  
Joan M. Kelly


1995 ◽  
Vol 73 (S1) ◽  
pp. 148-152 ◽  
Author(s):  
Herbert N. Arst Jr.

The paper of Arst and Cove (Mol. Gen. Genet. 126: 111 – 141, 1973) on "Nitrogen metabolite repression in Aspergillus nidulans" has influenced studies and perceptions of gene regulation in filamentous fungi during the past 21 years. Here I attempt to appraise the contributions of that paper and assess its role in further developments. Nitrogen metabolite repression, carbon catabolite repression, pathway-specific and integrated induction, as-acting regulatory mutations, a useful class of growth inhibitors, and a homologous Neurospora crassa gene are all discussed. Key words: Aspergillus nidulans, carbon catabolite repression, nitrogen metabolite repression.



1975 ◽  
Vol 51 (2) ◽  
pp. 573-577 ◽  
Author(s):  
Christopher BAILEY ◽  
Herbert N. ARST


2007 ◽  
Vol 189 (22) ◽  
pp. 8371-8376 ◽  
Author(s):  
José Manuel Inácio ◽  
Isabel de Sá-Nogueira

ABSTRACTInBacillus subtilis, the synthesis of enzymes involved in the degradation of arabinose-containing polysaccharides is subject to carbon catabolite repression (CCR). Here we show that CcpA is the major regulator of repression of the arabinases genes in the presence of glucose. CcpA acts via binding to onecreeach in the promoter regions of theabnAandxsagenes and to twocres in thearaABDLMNPQ-abfAoperon. The contributions of the coeffectors HPr and Crh to CCR differ according to growth phase. HPr dependency occurs during both exponential growth and the transitional phase, while Crh dependency is detected mainly at the transitional phase. Our results suggest that Crh synthesis may increase at the end of exponential growth and consequently contribute to this effect, together with other factors.



1998 ◽  
Vol 180 (23) ◽  
pp. 6242-6251 ◽  
Author(s):  
Christopher J. Stemple ◽  
Meryl A. Davis ◽  
Michael J. Hynes

ABSTRACT Mutations in the facC gene of Aspergillus nidulans result in an inability to use acetate as a sole carbon source. This gene has been cloned by complementation. The proposed translation product of the facC gene has significant similarity to carnitine acetyltransferases (CAT) from other organisms. Total CAT activity was found to be inducible by acetate and fatty acids and repressed by glucose. Acetate-inducible activity was found to be absent in facC mutants, while fatty acid-inducible activity was absent in an acuJ mutant. Acetate induction offacC expression was dependent on the facBregulatory gene, and an expressed FacB fusion protein was demonstrated to bind to 5′ facC sequences. Carbon catabolite repression of facC expression was affected by mutations in thecreA gene and a CreA fusion protein bound to 5′facC sequences. Mutations in the acuJ gene led to increased acetate induction of facC expression and also of an amdS-lacZ reporter gene, and it is proposed that this results from accumulation of acetate, as well as increased expression of facB. A model is presented in which facCencodes a cytosolic CAT enzyme, while a different CAT enzyme, which isacuJ dependent, is present in peroxisomes and mitochondria, and these activities are required for the movement of acetyl groups between intracellular compartments.





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