Specific binding sites in the alcR and alcA promoters of the ethanol regulon for the CREA repressor mediating carbon cataboiite repression in Aspergillus nidulans

Kulmburg, P; Mathieu, Martine; Dowzer, C. E. A.; Kelly, Joseph F.; Felenbok, Béatrice

doi:10.1111/j.1365-2958.1993.tb01175.x

Cited by 305 publications

(241 citation statements)

References 33 publications

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“…Within a 646-bp sequence upstream of the ATG, the following putative regulatory elements were identified: a TATA-like box at position Ϫ200; CCAAT elements at Ϫ49 and Ϫ486 bp relative to the ATG; and at position Ϫ328 an element (GTG GGG) meeting the consensus sequence (SYGGRG) for the binding of CREA, the broad domain regulator for carbon catabolite repression in Aspergillus (23). In addition, we found one putative bristle response element (AGAGGGG) at position Ϫ183 and two putative abacus response elements (CAT TCT) at positions Ϫ238 and Ϫ188, which correspond to binding sites for the development-specific transcription factors BRLA (4) and ABAA (1), respectively, in A. nidulans.…”

Section: Resultsmentioning

confidence: 99%

Mannitol Is Required for Stress Tolerance inAspergillus nigerConidiospores

et al. 2003

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D-Mannitol is the predominant carbon compound in conidiospores of the filamentous fungus Aspergillus niger and makes up 10 to 15% of the dry weight. A number of physiological functions have been ascribed to mannitol, including serving as a reserve carbon source, as an antioxidant, and to store reducing power. In this study, we cloned and characterized the A. niger mpdA gene, which encodes mannitol 1-phosphate dehydrogenase (MPD), the first enzyme in the mannitol biosynthesis pathway. The mpdA promoter contains putative binding sites for the development-specific transcription factors BRLA and ABAA. Furthermore, increased expression of mpdA in sporulating mycelium suggests that mannitol biosynthesis is, to a certain extent, developmentally regulated in A. niger. Inactivation of mpdA abolished mannitol biosynthesis in growing mycelium and reduced the mannitol level in conidiospores to 30% that in the wild type, indicating that MPD and mannitol 1-phosphate phosphatase form the major metabolic pathway for mannitol biosynthesis in A. niger. The viability of spores after prolonged storage and germination kinetics were normal in an mpdA null mutant, indicating that mannitol does not play an essential role as a reserve carbon source in A. niger conidia. However, conidiospores of a ⌬mpdA strain were extremely sensitive to a variety of stress conditions, including high temperature, oxidative stress and, to a lesser extent, freezing and lyophilization. Since mannitol supplied in the medium during sporulation repaired this deficiency, mannitol appears to be essential for the protection of A. niger spores against cell damage under these stress conditions. Polyols or polyhydroxyalcohols are present in all organisms, from bacteria to animals. In particular, plants and fungi are known to accumulate high levels of polyols intracellularly, up to several hundred millimoles per liter. The filamentous fungus Aspergillus niger produces a number of different polyols, including glycerol, erythritol, and D-mannitol (41). The intracellular concentrations of the individual polyols in A. niger depend on growth conditions and developmental stage, suggesting that polyols have important functions in fungal physiology.The hexitol D-mannitol is accumulated by vascular plants (37) and many fungal species (21). In A. niger conidiospores, D-mannitol is the predominant carbon-containing compound and makes up 10 to 15% of the dry weight (41). The metabolic pathway for mannitol biosynthesis in ascomycete and deuteromycete fungi most likely consists of two steps (19) (Fig. 1). Fructose 6-phosphate is reduced to mannitol 1-phosphate by NAD ϩ -dependent mannitol 1-phosphate dehydrogenase (MPD), followed by the dephosphorylation of mannitol 1-phosphate, which is catalyzed by mannitol 1-phosphate phosphatase (MPP), yielding mannitol. The presence of MPD and MPP in several fungi, such as A. niger (22), Aspergillus nidulans (34), and Alternaria alternata (18), has been demonstrated, but these enzymes are also responsible for mannitol biosynthesis in protozoa...

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Section: Resultsmentioning

confidence: 99%

Mannitol Is Required for Stress Tolerance inAspergillus nigerConidiospores

et al. 2003

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“…Both types of sites have been shown to be functional in vivo (15,16). 2,3 Surprisingly, the interactions between the AlcR fusion proteins and guanines within the motif appeared to be different in both types of targets (14,15).…”

Section: Three Different Bacterially Expressed Alcr Proteins-previ-mentioning

confidence: 99%

“…Furthermore, unlike the other members of this family, AlcR appears to bind with the same affinity to both symmetric and asymmetric sites containing the consensus motif 5Ј-CCGCA-3Ј (14,15). Both types of targets localized in the alcR and alcA promoters have been shown to be functional in vivo (15,16).…”

mentioning

confidence: 99%

“…The GST fusion protein system was successfully used to determine the DNA-binding sites for a number of proteins such as SWI5 in yeast (18), N-Myc in mouse (19), and T/E1A in human (20). In A. nidulans, binding sites for the CreA repressor (16) and NirA (21) and UaY (6) activators have been localized using GST fusion proteins. The binding sites have been shown to be functional in vivo, as for AlcRbinding sites.…”

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confidence: 99%

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In Vitro Recognition of Specific DNA Targets by AlcR, a Zinc Binuclear Cluster Activator Different from the Other Proteins of This Class

Lenouvel

Nikolaev

Felenbok

1997

Journal of Biological Chemistry

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AlcR is the transactivator mediating transcriptional induction of the alc gene cluster in Aspergillus nidulans. The AlcR DNA-binding domain consists of a zinc binuclear cluster different from the other members of the Zn 2 Cys 6 family by several features. In particular, it is able to bind to symmetric and asymmetric sites with the same affinity, with both sites being functional in A. nidulans. Here, we show that unlike the other proteins of the Zn 2 Cys 6 binuclear cluster family, AlcR binds most probably as a monomer to its cognate targets. Two molecules of the AlcR protein can simultaneously bind in a noncooperative manner to inverted repeats. The consensus core has been determined precisely (5 -CCGCN-3 ), and the AlcR-binding site in the aldA promoter has been localized. The sequence downstream of the zinc cluster is necessary for high affinity binding. Furthermore, our data show that the use of the carrier protein glutathione S-transferase in AlcR binding experiments introduces an important bias in the recognition of DNA sites due to its tertiary dimeric structure.

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“…In the promoters of these three genes several putative CREA-binding sites, i.e. sequence elements identical to the A. nidulans CREA motif 5'-G/CPyG GPuG-3' (Kulmburg et al, 1993;Cubero & Scazzocchio, 1994) as well as some elements common to all arabinase genes can be found . Although the A .…”

Section: Introductionmentioning

confidence: 99%

Isolation of Aspergillus niger creA mutants and effects of the mutations on expression of arabinases and L-arabinose catabolic enzymes

Ruijter¹,

Vanhanen²,

Gielkens³

et al. 1997

Microbiology

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Aspergillus niger mutants relieved of carbon repression were isolated from an areA parental strain by selection of colonies that exhibited improved growth on a combination of 4-aminobutanoic acid (GABA) and D-glucose. In addition to derepression of the utilization of GABA as a nitrogen source in the presence of D-glucose, three of the four mutants also showed derepression of Lalanine and L-proline utilization. Transformation of the mutants with the A. niger creA gene, encoding the repressor protein CREA, re-established the areA phenotype on GABND-glucose, identifying the mutations as creAd. The creA gene mapped on chromosome IV by linkage analysis and contour-clamped homogeneous electric field hybridization. The creA mutants obtained were used to study the involvement of CREA in repression by D-glucose of arabinases and L-arabinose catabolism in A. niger. In wild-type A. niger, a-L-arabinofuranosidase A, a+ arabinof uranosidase B, endo-arabinase, L-arabinose reductase and L-arabitol dehydrogenase were induced on L-arabinose, but addition of D-glucose prevented this induction. Repression was relieved to varying degrees in the creA mutants, showing that biosynthesis of arabinaoes and L-arabinose catabolic enzymes is under control of CREA.1

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Specific binding sites in the alcR and alcA promoters of the ethanol regulon for the CREA repressor mediating carbon cataboiite repression in Aspergillus nidulans

Cited by 305 publications

References 33 publications

Mannitol Is Required for Stress Tolerance inAspergillus nigerConidiospores

Mannitol Is Required for Stress Tolerance inAspergillus nigerConidiospores

In Vitro Recognition of Specific DNA Targets by AlcR, a Zinc Binuclear Cluster Activator Different from the Other Proteins of This Class

Isolation of Aspergillus niger creA mutants and effects of the mutations on expression of arabinases and L-arabinose catabolic enzymes

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