Identification, cloning and analysis of theAspergillus niger genepacC, a wide domain regulatory gene responsive to ambient pH

MacCabe, Andrew; Hombergh, J. P. T. W. van den; Tilburn, Joan; Arst, Herbert N.; Visser, Jaap

doi:10.1007/bf02174395

Cited by 47 publications

(52 citation statements)

References 28 publications

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“…As noted in several sections of this review, homologues of A. nidulans pacC have been identified in a number of filamentous ascomycetes, including A. niger (76) the identified genes involved in pH regulation in A. nidulans, including palC. As described in detail in the following sections, the budding yeast Saccharomyces cerevisiae and two dimorphic yeasts, Candida albicans and Yarrowia lipolytica, also have homologues of the pH regulatory system genes, with the sole exception of palC.…”

Section: Presence Of the Ph Regulatory System Homologues In Other Fungimentioning

confidence: 85%

“…An eye-catching feature is the presence of three perfect copies and one imperfect copy of a 6-residue direct repeat in which the perfect copies contain only acidic and glutamine residues (122). Its significance is unclear but is not likely to be great, since it is not present in isofunctional homologues from organisms as closely related as Aspergillus niger and Penicillium chrysogenum (76,119).…”

Section: Pacc Transcription Factormentioning

confidence: 99%

“…A. niger is an important producer of extracellular enzymes, many of which are subject to pacC-mediated pH regulation (61,76,126,127). In another example, ambient pH influences both the production and glycosylation of A. niger glucoamylase (131).…”

Section: Enzyme Productionmentioning

confidence: 99%

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Regulation of Gene Expression by Ambient pH in Filamentous Fungi and Yeasts

Peñalva

Arst

2002

Microbiol Mol Biol Rev

271

213

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Life, as we know it, is water based. Exposure to hydroxonium and hydroxide ions is constant and ubiquitous, and the evolutionary pressure to respond appropriately to these ions is likely to be intense. Fungi respond to their environments by tailoring their output of activities destined for the cell surface or beyond to the ambient pH. We are beginning to glimpse how they sense ambient pH and transmit this information to the transcription factor, whose roles ensure that a suitable collection of gene products will be made. Although relatively little is known about pH signal transduction itself, its consequences for the cognate transcription factor are much clearer. Intriguingly, homologues of components of this system mediating the regulation of fungal gene expression by ambient pH are to be found in the animal kingdom. The potential applied importance of this regulatory system lies in its key role in fungal pathogenicity of animals and plants and in its control of fungal production of toxins, antibiotics, and secreted enzymes

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Section: Presence Of the Ph Regulatory System Homologues In Other Fungimentioning

confidence: 85%

Section: Pacc Transcription Factormentioning

confidence: 99%

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Regulation of Gene Expression by Ambient pH in Filamentous Fungi and Yeasts

Peñalva

Arst

2002

Microbiol Mol Biol Rev

271

213

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“…Finally, our work with PacC is relevant for understanding the invasiveness and resistance to alkaline pH in Saccharomyces (22,34), the adaptation of Candida albicans to changing pH environments (a key factor in its pathogenicity) (11,12,49,50), the synthesis of extracellular metabolites and proteins by fungi (19,33,35,36,38,56,61,62), and the regulation of aflatoxin biosynthesis (32), all of which are processes regulated by the PacC/RIM101p family of transcription factors. FIG.…”

Section: Discussionmentioning

confidence: 99%

Ambient pH Signaling Regulates Nuclear Localization of the Aspergillus nidulans PacC Transcription Factor

Mingot

Espeso

Díez

et al. 2001

Molecular and Cellular Biology

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The Aspergillus nidulans zinc finger transcription factor PacC is activated by proteolytic processing in response to ambient alkaline pH. The pH-regulated step is the transition of full-length PacC from a closed to an open, protease-accessible conformation. Here we show that in the absence of ambient pH signaling, the C-terminal negative-acting domain prevents the nuclear localization of full-length closed PacC. In contrast, the processed PacC form is almost exclusively nuclear at any ambient pH. In the presence of ambient pH signaling, the fraction of PacC that is in the open conformation but has not yet been processed localizes to the nucleus. Therefore, ambient alkaline pH leads to an increase in nuclear PacC by promoting the proteolytic elimination of the negative-acting domain to yield the processed form and by increasing the proportion of full-length protein that is in the open conformation. These findings explain why mutations resulting in commitment of PacC to processing irrespective of ambient pH lead to permanent PacC activation and alkalinity mimicry. A nuclear import signal that targets Escherichia coli ␤-galactosidase to the nucleus has been located to the PacC zinc finger region. A mutation abolishing DNA binding does not prevent nuclear localization of the processed form, showing that PacC processing does not lead to nuclear localization by passive diffusion of the protein made possible by the reduction in size, followed by retention in the nucleus after DNA binding.Proteolytic processing activation of transcription factors in response to their cognate environmental signals occurs across distant groups of eukaryotic organisms. pH regulation of gene expression in the mold Aspergillus nidulans is one such example. Here, the key regulatory zinc finger protein PacC activates alkaline genes and represses acidic genes according to the needs imposed by ambient pH, thereby providing the organism with one prerequisite for growing in environments as acidic as pH 2.5 or as alkaline as pH 10.5 (7, 59). Other prototypical members of the group of transcription factors activated by proteolytic processing are the immune and inflammatory response regulator NF-B (23, 58), the Drosophila melanogaster cubitus interruptus (Ci) zinc finger factor (the transducer of the hedgehog signal) (29, 53), and the sterol regulatory elementbinding protein (SREBP), which switches on genes for cholesterol biosynthesis and fat metabolism (5, 6).The zinc finger transcription factor PacC is synthesized as a 674-residue precursor. At alkaline ambient pH, a signal transmitted to PacC by the orphan pal gene signal transduction pathway (13,14,37,43,44) results in a conformational change leading to an open conformation in which PacC is accessible to a processing protease (18,41,47). This protease removes ϳ400 residues from the C terminus, which includes a negative-acting domain. The resulting product (248 to 250 residues) (41) is fully competent in transcriptional regulation through 5Ј-GCC ARG-3Ј sites (20) in the promoters of both alkaline...

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“…The gene encoding this protein (pacC) has been cloned from A. nidulans (368) and was shown to complement A. nidulans pHregulatory mutants, previously isolated as mutants defective in phosphatase expression (16,18,98). An A. niger homologue has also been cloned (240). PacC is activated under alkaline conditions by proteolytic modification of the C-terminal region, which enables it to bind to specific target sites (GCCA RG, with R being A or G) in the promoter of target genes (276).…”

Section: Ph-dependent Expressionmentioning

confidence: 99%

AspergillusEnzymes Involved in Degradation of Plant Cell Wall Polysaccharides

Vries

Visser

2001

Microbiol Mol Biol Rev

885

585

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SUMMARY Degradation of plant cell wall polysaccharides is of major importance in the food and feed, beverage, textile, and paper and pulp industries, as well as in several other industrial production processes. Enzymatic degradation of these polymers has received attention for many years and is becoming a more and more attractive alternative to chemical and mechanical processes. Over the past 15 years, much progress has been made in elucidating the structural characteristics of these polysaccharides and in characterizing the enzymes involved in their degradation and the genes of biotechnologically relevant microorganisms encoding these enzymes. The members of the fungal genus Aspergillus are commonly used for the production of polysaccharide-degrading enzymes. This genus produces a wide spectrum of cell wall-degrading enzymes, allowing not only complete degradation of the polysaccharides but also tailored modifications by using specific enzymes purified from these fungi. This review summarizes our current knowledge of the cell wall polysaccharide-degrading enzymes from aspergilli and the genes by which they are encoded.

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Identification, cloning and analysis of theAspergillus niger genepacC, a wide domain regulatory gene responsive to ambient pH

Cited by 47 publications

References 28 publications

Regulation of Gene Expression by Ambient pH in Filamentous Fungi and Yeasts

Regulation of Gene Expression by Ambient pH in Filamentous Fungi and Yeasts

Ambient pH Signaling Regulates Nuclear Localization of the Aspergillus nidulans PacC Transcription Factor

AspergillusEnzymes Involved in Degradation of Plant Cell Wall Polysaccharides

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