The ethanol regulon in Aspergillus nidulans: characterization and sequence of the positive regulatory gene alcR

Gene ◽  
1988 ◽  
Vol 73 (2) ◽  
pp. 385-396 ◽  
Author(s):  
Béatrice Felenbok ◽  
Daria Sequeval ◽  
Martine Mathieu ◽  
Susan Sibley ◽  
David I. Gwynne ◽  
...  
Keyword(s):  
Aspergillus Nidulans ◽  
Regulatory Gene

The Aspergillus nidulans abaA gene encodes a transcriptional activator that acts as a genetic switch to control development

1994 ◽  
Vol 14 (4) ◽  
pp. 2503-2515
Author(s):  
A Andrianopoulos ◽  
W E Timberlake
Keyword(s):  
Aspergillus Nidulans ◽  
Transcriptional Activation ◽  
Expression System ◽  
Regulatory Gene ◽  
Binding Motif ◽  
Mobility Shift ◽  
Genetic Switch ◽  
Regulatory Regions ◽  
Cis Acting ◽  
Gel Mobility Shift

The Aspergillus nidulans abaA gene encodes a protein containing an ATTS DNA-binding motif and is required for the terminal stages of conidiophore development. Results from gel mobility shift and protection, missing-contact, and interference footprint assays showed that AbaA binds to the sequence 5'-CATTCY-3', where Y is a pyrimidine, making both major- and minor-groove contacts. Multiple AbaA binding sites are present in the cis-acting regulatory regions of several developmentally controlled structural genes as well as those of the upstream regulatory gene brlA, the downstream regulatory gene wetA, and abaA itself. These cis-acting regulatory regions confer AbaA-dependent transcriptional activation in a heterologous Saccharomyces cerevisiae gene expression system. From these observations, we propose that the AbaA transcription factor establishes a novel set of feedback regulatory loops responsible for determination of conidiophore development.

Identification of developmental regulatory genes in Aspergillus nidulans by overexpression.

Genetics ◽  
1995 ◽  
Vol 139 (2) ◽  
pp. 537-547 ◽  
Author(s):  
J F Marhoul ◽  
T H Adams
Keyword(s):  
Growth Inhibition ◽  
Aspergillus Nidulans ◽  
Genomic Dna ◽  
Regulatory Gene ◽  
Regulatory Genes ◽  
Dna Fragments ◽  
Expression Library ◽  
Phenotypic Changes ◽  
Inhibition Of Growth ◽  
Induction Sequence

Abstract Overexpression of several Aspergillus nidulans developmental regulatory genes has been shown to cause growth inhibition and development at inappropriate times. We set out to identify previously unknown developmental regulators by constructing a nutritionally inducible A. nidulans expression library containing small, random genomic DNA fragments inserted next to the alcA promoter [alcA(p)] in an A. nidulans transformation vector. Among 20,000 transformants containing random alcA(p) genomic DNA fusion constructs, we identified 66 distinct mutant strains in which alcA(p) induction resulted in growth inhibition as well as causing other detectable phenotypic changes. These growth inhibited mutants were divided into 52 FIG (Forced expression Inhibition of Growth) and 14 FAB (Forced expression Activation of brlA) mutants based on whether or not alcA(p) induction resulted in accumulation of mRNA for the developmental regulatory gene brlA. In four FAB mutants, alcA(p) induction not only activated brlA expression but also caused hyphae to differentiate into reduced conidiophores that produced viable spores from the tips as is observed after alcA(p)::brlA induction. Sequence analyses of the DNA fragments under alcA(p) control in three of these four sporulating strains showed that in two cases developmental activation resulted from overexpression of previously uncharacterized genes, whereas in the third strain, the alcA(p) was fused to brlA. The potential uses for this strategy in identifying genes whose overexpression results in specific phenotypic changes like developmental induction are discussed.

Regulation of alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (AldDH) in Aspergillus nidulans

1983 ◽  
Vol 217 (1208) ◽  
pp. 243-264 ◽  
Keyword(s):  
Alcohol Dehydrogenase ◽  
Aspergillus Nidulans ◽  
Structural Gene ◽  
Aldehyde Dehydrogenase ◽  
Gel Electrophoresis ◽  
Regulatory Gene ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Wild Type ◽  
Cell Extracts

There is a single major alcohol dehydrogenase (ADH) and a single major aldehyde dehydrogenase (AldDH) in Aspergillus nidulans . Both ADH and AldDH are induced by ethanol and by acetaldehyde and both are subject to carbon catabolite repression. ADH and AldDH are necessary for the utilization of ethanol and of threonine, indicating that both compounds are utilized via acetaldehyde. ADH and AldDH each give a single major activity band on gel electrophoresis. Sodium dodecyl sulphate polyacrylamide gel electrophoresis of cell extracts shows at least two similar ADH polypeptides of approximate relative molecular mass (r. m. m.) 41000 and two similar AldDH polypeptides of approximate r. m. m. 57000. The in vitro translation of mRNA from induced, carbon derepressed wild-type cells gives up to three ADH polypeptides in the r. m. m. range 39000-43000 and an AldDH polypeptide of approximate r. m. m. 57000. The mRNA from uninduced, carbon repressed wild-type cells does not direct the synthesis of the ADH and AldDH polypeptides. This indicates that the regulation of ADH and AldDH is at the level of transcription and/or post-transcriptional modification. The probable explanation of the multiple ADH polypeptides is post-transcriptional modification of the mRNA. Allyl alcohol mutants were made by using diepoxyoctane and γ-rays as mutagens. There are two classes, alcA and alcR . Neither class can utilize ethanol or threonine as a carbon source. The alcA mutants lack normal ADH and are recessive. Of the 47 alcA mutants examined 39 do not make the ADH polypeptides while eight do so. Therefore alcA is the structural gene for ADH. The two alcA mutants tested do not make functional mRNA for ADH. The alcR mutants lack both ADH and AldDH and are recessive. No alcR mutants make the ADH or the AldDH polypeptides. The three alcR mutants tested do not make functional ADH or AldDH mRNA. The mutant alcR 125 is a nonsense mutant, which establishes that alcR codes for a protein. The alcA and alcR genes are adjacent on chromosome VII and a preliminary fine-structure map of the alcA gene has been made. Three mutants that cannot utilize ethanol or threonine and have ADH, but lack AldDH, define a gene AldA on chromosome VIII. The aldA 23 mutant makes the AldDH polypeptides, the other two aldA mutants do not. Therefore aldA is probably the structural gene for AldDH. Our current hypothesis is that alcA and aldA are the structural genes for ADH and AldDH respectively and alcR is a transacting regulatory gene coding for a protein whose function is necessary for the expression of the alcA and aldA genes.

scholarly journals The Aspergillus nidulans abaA gene encodes a transcriptional activator that acts as a genetic switch to control development.

1994 ◽  
Vol 14 (4) ◽  
pp. 2503-2515 ◽  
Author(s):  
A Andrianopoulos ◽  
W E Timberlake
Keyword(s):  
Aspergillus Nidulans ◽  
Transcriptional Activation ◽  
Expression System ◽  
Regulatory Gene ◽  
Binding Motif ◽  
Mobility Shift ◽  
Genetic Switch ◽  
Regulatory Regions ◽  
Cis Acting ◽  
Gel Mobility Shift

The Aspergillus nidulans abaA gene encodes a protein containing an ATTS DNA-binding motif and is required for the terminal stages of conidiophore development. Results from gel mobility shift and protection, missing-contact, and interference footprint assays showed that AbaA binds to the sequence 5'-CATTCY-3', where Y is a pyrimidine, making both major- and minor-groove contacts. Multiple AbaA binding sites are present in the cis-acting regulatory regions of several developmentally controlled structural genes as well as those of the upstream regulatory gene brlA, the downstream regulatory gene wetA, and abaA itself. These cis-acting regulatory regions confer AbaA-dependent transcriptional activation in a heterologous Saccharomyces cerevisiae gene expression system. From these observations, we propose that the AbaA transcription factor establishes a novel set of feedback regulatory loops responsible for determination of conidiophore development.

scholarly journals Sequence and functional analysis of the positively acting regulatory gene amdR from Aspergillus nidulans.

1990 ◽  
Vol 10 (6) ◽  
pp. 3194-3203 ◽  
Author(s):  
A Andrianopoulos ◽  
M J Hynes
Keyword(s):  
Dna Binding ◽  
Aspergillus Nidulans ◽  
Nuclear Localization ◽  
Regulatory Gene ◽  
Transcription Activation ◽  
Binding Motif ◽  
Wild Type ◽  
Amino Terminal ◽  
Carboxyl Terminal

The positively acting regulatory gene amdR of Aspergillus nidulans coordinately regulates the expression of five structural genes involved in the catabolism of certain amides (amdS), omega amino acids (gatA and gabA), and lactams (lamA and lamB) in the presence of omega amino acid inducers. Analysis of the amdR gene showed that it contains three small introns, heterogeneous 5' and 3' transcription sites, and multiple AUG codons prior to the major AUG initiator. The predicted amdR protein sequence has a cysteine-rich "zinc finger" DNA-binding motif at the amino-terminal end, four putative acidic transcription activation motifs in the carboxyl-terminal half, and two sequences homologous to the simian virus 40 large T antigen nuclear localization motif. These nuclear localization sequences overlap the cysteine-rich DNA-binding motif. A series of 5', 3', and internal deletions were examined in vivo for transcription activator function and showed that the amdR product contains at least two activation regions in the carboxyl-terminal half. Each of these activator amdR product contains at least two activation regions in the carboxyl-terminal half. Each of these activator regions may function independently, but both are required for wild-type levels of transcription activation. A number of the amdR deletion products were found to compete with the wild-type amdR product in vivo. Development of a rapid method for the localization of amdR mutations is presented, and using this technique, we localized and sequenced the mutation in the semiconstitutive amdR6c allele. The amdR6c missense mutation occurs in the middle of the gene, and it is suggested that it results in an altered protein which activates gene expression efficiently in the absence of an inducer.

scholarly journals nirA, the pathway-specific regulatory gene of nitrate assimilation in Aspergillus nidulans, encodes a putative GAL4-type zinc finger protein and contains four introns in highly conserved regions.

1991 ◽  
Vol 11 (11) ◽  
pp. 5746-5755 ◽  
Author(s):  
G Burger ◽  
J Strauss ◽  
C Scazzocchio ◽  
B F Lang
Keyword(s):  
Amino Acids ◽  
Aspergillus Nidulans ◽  
Zinc Finger ◽  
Zinc Finger Protein ◽  
Regulatory Gene ◽  
Wild Type ◽  
Transcript Levels ◽  
Amino Terminal ◽  
Nitrate And Nitrite ◽  
Acidic Region

The nucleotide sequence of nirA, mediating nitrate induction in Aspergillus nidulans, has been determined. Alignment of the cDNA and the genomic DNA sequence indicates that the gene contains four introns and encodes a protein of 892 amino acids. The deduced NIRA protein displays all characteristics of a transcriptional activator. A putative double-stranded DNA-binding domain in the amino-terminal part comprises six cysteine residues, characteristic for the GAL4 family of zinc finger proteins. An amino-terminal highly acidic region and two proline-rich regions are also present. The nucleotide sequences of two mutations were determined after they were mapped by transformation with overlapping DNA fragments, amplified by the polymerase chain reaction. nirA87, a mutation conferring noninducibility by nitrate and nitrite, has a -1 frameshift at triplet 340, which eliminates 549 C-terminal amino acids from the polypeptide. Under the assumption that the truncated polypeptide is stable, it comprises the zinc finger domain and the acidic region, which seem not sufficient for transcriptional activation. nirAd-106, an allele conferring nitrogen metabolite derepression of nitrate and nitrite reductase activity, includes two transitions, changing a glutamic acid to a lysine and a valine to an alanine, situated between a basic and a proline-rich region of the protein. Northern (RNA) analysis of the wild type and of constitutive (nirAc) and derepressed (nirAd) mutants show that the nirA transcript does not vary between these strains, being in all cases constitutively expressed. On the other hand, transcript levels of structural genes (niaD and niiA) do vary, being highly inducible in the wild type but constitutively expressed in the nirAc mutant. The nirAd mutant appears phenotypically derepressed, because the niaD and niiA transcript levels are overinduced in the presence of nitrate but are still partially repressed in the presence of ammonium.

Cloning and analysis of the positively acting regulatory gene amdR from Aspergillus nidulans

1988 ◽  
Vol 8 (8) ◽  
pp. 3532-3541
Author(s):  
A Andrianopoulos ◽  
M J Hynes
Keyword(s):  
Aspergillus Nidulans ◽  
Blot Analysis ◽  
Regulatory Gene ◽  
Regulation Of Gene Expression ◽  
Strong Support ◽  
Cosmid Library ◽  
Loss Of Function ◽  
Structural Genes ◽  
Dna Rearrangements ◽  
Multiple Copies

The positively acting regulatory gene amdR of Aspergillus nidulans coordinately regulates the expression of four unlinked structural genes involved in acetamide (amdS), omega amino acid (gatA and gabA), and lactam (lamA) catabolism. By the use of DNA-mediated transformation of A. nidulans, the amdR regulatory gene was cloned from a genomic cosmid library. Southern blot analysis of DNA from various loss-of-function amdR mutants revealed the presence of four detectable DNA rearrangements, including a deletion, an insertion, and a translocation. No detectable DNA rearrangements were found in several constitutive amdRc mutants. Analysis of the fate of amdR-bearing plasmids in transformants showed that 10 to 20% of the transformation events were homologous integrations or gene conversions, and this phenomenon was exploited in developing a strategy by which amdRc and amdR- alleles can be readily cloned and analyzed. Examination of the transcription of amdR by Northern blot (RNA blot) analysis revealed the presence of two mRNAs (2.7 and 1.8 kilobases) which were constitutively synthesized at a very low level. In addition, amdR transcription did not appear to depend on the presence of a functional amdR product nor was it altered in amdRc mutants. The dosage effects of multiple copies of amdR in transformants were examined, and it was shown that such transformants exhibited stronger growth than did the wild type on acetamide and pyrrolidinone media, indicating increased expression of the amdS and lamA genes, respectively. These results were used to formulate a model for amdR-mediated regulation of gene expression in which the low constitutive level of amdR product sets the upper limits of basal and induced transcription of the structural genes. Multiple copies of 5' sequences from the amdS gene can result in reduced growth on substrates whose utilization is dependent on amdR-controlled genes. This has been attributed to titration of limiting amdR gene product. Strong support for this proposal was obtained by showing that multiple copies of the amdR gene can reverse this phenomenon (antititration).

scholarly journals Cloning and analysis of the positively acting regulatory gene amdR from Aspergillus nidulans.

1988 ◽  
Vol 8 (8) ◽  
pp. 3532-3541 ◽  
Author(s):  
A Andrianopoulos ◽  
M J Hynes
Keyword(s):  
Aspergillus Nidulans ◽  
Blot Analysis ◽  
Regulatory Gene ◽  
Regulation Of Gene Expression ◽  
Strong Support ◽  
Cosmid Library ◽  
Loss Of Function ◽  
Structural Genes ◽  
Dna Rearrangements ◽  
Multiple Copies

The positively acting regulatory gene amdR of Aspergillus nidulans coordinately regulates the expression of four unlinked structural genes involved in acetamide (amdS), omega amino acid (gatA and gabA), and lactam (lamA) catabolism. By the use of DNA-mediated transformation of A. nidulans, the amdR regulatory gene was cloned from a genomic cosmid library. Southern blot analysis of DNA from various loss-of-function amdR mutants revealed the presence of four detectable DNA rearrangements, including a deletion, an insertion, and a translocation. No detectable DNA rearrangements were found in several constitutive amdRc mutants. Analysis of the fate of amdR-bearing plasmids in transformants showed that 10 to 20% of the transformation events were homologous integrations or gene conversions, and this phenomenon was exploited in developing a strategy by which amdRc and amdR- alleles can be readily cloned and analyzed. Examination of the transcription of amdR by Northern blot (RNA blot) analysis revealed the presence of two mRNAs (2.7 and 1.8 kilobases) which were constitutively synthesized at a very low level. In addition, amdR transcription did not appear to depend on the presence of a functional amdR product nor was it altered in amdRc mutants. The dosage effects of multiple copies of amdR in transformants were examined, and it was shown that such transformants exhibited stronger growth than did the wild type on acetamide and pyrrolidinone media, indicating increased expression of the amdS and lamA genes, respectively. These results were used to formulate a model for amdR-mediated regulation of gene expression in which the low constitutive level of amdR product sets the upper limits of basal and induced transcription of the structural genes. Multiple copies of 5' sequences from the amdS gene can result in reduced growth on substrates whose utilization is dependent on amdR-controlled genes. This has been attributed to titration of limiting amdR gene product. Strong support for this proposal was obtained by showing that multiple copies of the amdR gene can reverse this phenomenon (antititration).

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