scholarly journals A Gene from Aspergillus nidulans with Similarity to URE2 of Saccharomyces cerevisiae Encodes a Glutathione S-Transferase Which Contributes to Heavy Metal and Xenobiotic Resistance

2002 ◽  
Vol 68 (6) ◽  
pp. 2802-2808 ◽  
Author(s):  
James A. Fraser ◽  
Meryl A. Davis ◽  
Michael J. Hynes
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Aspergillus Nidulans ◽  
Deletion Mutant ◽  
Regulatory System ◽  
Nitrogen Sources ◽  
Northern Analysis ◽  
Systemic Fungicide ◽  
Glutathione S Transferase ◽  
Cloning And Sequencing ◽  
Nitrogen Metabolite Repression

ABSTRACT Aspergillus nidulans is a saprophytic ascomycete that utilizes a wide variety of nitrogen sources. We identified a sequence from A. nidulans similar to the glutathione S-transferase-like nitrogen regulatory domain of Saccharomyces cerevisiae Ure2. Cloning and sequencing of the gene, designated gstA, revealed it to be more similar to URE2 than the S. cerevisiae glutathione S-transferases. However, creation and analysis of a gstA deletion mutant revealed that the gene does not participate in nitrogen metabolite repression. Instead, it encodes a functional theta class glutathione S-transferase that is involved in resistance to a variety of xenobiotics and metals and confers susceptibility to the systemic fungicide carboxin. Northern analysis showed that gstA transcription is strongly activated upon exposure to 1-chloro-2,4-dinitrobenzene and weakly activated by oxidative stress or growth on galactose as a carbon source. These results suggest that nitrogen metabolite repression in A. nidulans does not involve a homolog of the S. cerevisiae URE2 gene and that the global nitrogen regulatory system differs significantly in these two fungi.

scholarly journals HbxB Is a Key Regulator for Stress Response and β-Glucan Biogenesis in Aspergillus nidulans

2021 ◽  
Vol 9 (1) ◽  
pp. 144
Author(s):  
Sung-Hun Son ◽  
Mi-Kyung Lee ◽  
Ye-Eun Son ◽  
Hee-Soo Park
Keyword(s):  
Transcription Factor ◽  
Transcription Factors ◽  
Aspergillus Nidulans ◽  
Deletion Mutant ◽  
Phenotypic Analysis ◽  
Spore Viability ◽  
Fungal Development ◽  
Expression Of Genes ◽  
Trehalose Biosynthesis

Homeobox transcription factors are conserved in eukaryotes and act as multi-functional transcription factors in filamentous fungi. Previously, it was demonstrated that HbxB governs fungal development and spore viability in Aspergillus nidulans. Here, the role of HbxB in A. nidulans was further characterized. RNA-sequencing revealed that HbxB affects the transcriptomic levels of genes associated with trehalose biosynthesis and response to thermal, oxidative, and radiation stresses in asexual spores called conidia. A phenotypic analysis found that hbxB deletion mutant conidia were more sensitive to ultraviolet stress. The loss of hbxB increased the mRNA expression of genes associated with β-glucan degradation and decreased the amount of β-glucan in conidia. In addition, hbxB deletion affected the expression of the sterigmatocystin gene cluster and the amount of sterigmatocystin. Overall, these results indicated that HbxB is a key transcription factor regulating trehalose biosynthesis, stress tolerance, β-glucan degradation, and sterigmatocystin production in A.nidulans conidia.

scholarly journals Studies on the Role of the are a Gene in the Regulation of Nitrogen Catabolism in Aspergillus nidulans

1975 ◽  
Vol 28 (3) ◽  
pp. 301 ◽  
Author(s):  
MJ Hynes
Keyword(s):  
Nitrogen Source ◽  
Aspergillus Nidulans ◽  
Carbon Sources ◽  
Nitrogen Sources ◽  
Selection Methods ◽  
Growth Responses ◽  
Dominance Relationships ◽  
Regulatory Circuits ◽  
Specific Activities

Mutants of Apergillus nidulanswith lesions in a gene, areA (formerly called amdT), have been isolated by a variety of different selection methods. The areA mutants show a range of pleiotropic growth responses to a number of compounds as sole nitrogen sources, but are normal in utilization of carbon sources. The levels of two amidase enzymes as well as urease have been investigated in the mutants and have been shown to be affected by this gene. Most of the areA mutants have much lower amidase-specific activities when grown in ammonium-containing medium, compared with mycelium incubated in medium la9king a nitrogen source. Some of the areA. mutants do not show derepression of urease upon relief of ammonium repression. The dominance relationships of areA alleles have been investigated in� heterozygous diploids, and these studies lend support to the proposal that areA codes for a positively acting regulatory product. One of the new areA alleles is partially dominant to areA + and areA102. This may be a result of negative complementation or indicate that areA has an additional negative reiuIatory function. Investigation.of various amdR; areA double mutants has led to the conclusion that amdR and areA participate in independent regulatory circuits in the control of acetamide utilizatiol1. Studies on an amdRc; areA.double mutant indicate that areA is involved in derepression of acetamidase upon relief of ammo.nium repression.

Mutational analysis of the Saccharomyces cerevisiae SNF1 protein kinase and evidence for functional interaction with the SNF4 protein

1989 ◽  
Vol 9 (11) ◽  
pp. 5034-5044
Author(s):  
J L Celenza ◽  
M Carlson
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Kinase ◽  
Mutational Analysis ◽  
Gene Dosage ◽  
Regulatory System ◽  
Kinase Domain ◽  
Regulatory Function ◽  
Protein Kinase Activity ◽  
Glucose Limitation

The SNF1 gene of Saccharomyces cerevisiae encodes a protein-serine/threonine kinase that is required for derepression of gene expression in response to glucose limitation. We present evidence that the protein kinase activity is essential for SNF1 function: substitution of Arg for Lys in the putative ATP-binding site results in a mutant phenotype. A polyhistidine tract near the N terminus was found to be dispensable. Deletion of the large region C terminal to the kinase domain only partially impaired SNF1 function, causing expression of invertase to be somewhat reduced but still glucose repressible. The function of the SNF4 gene, another component of the regulatory system, was required for maximal in vitro activity of the SNF1 protein kinase. Increased SNF1 gene dosage partially alleviated the requirement for SNF4. C-terminal deletions of SNF1 also reduced dependence on SNF4. Our findings suggest that SNF4 acts as a positive effector of the kinase but does not serve a regulatory function in signaling glucose availability.

Sequence and expression of the dCMP deaminase gene (DCD1) of Saccharomyces cerevisiae

1986 ◽  
Vol 6 (5) ◽  
pp. 1711-1721
Author(s):  
E M McIntosh ◽  
R H Haynes
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Sequences ◽  
Open Reading Frame ◽  
Northern Analysis ◽  
Hindiii Site ◽  
Reading Frame ◽  
Hindiii Restriction Site ◽  
Cycle Dependent

The dCMP deaminase gene (DCD1) of Saccharomyces cerevisiae has been isolated by screening a Sau3A clone bank for complementation of the dUMP auxotrophy exhibited by dcd1 dmp1 haploids. Plasmid pDC3, containing a 7-kilobase (kb) Sau3A insert, restores dCMP deaminase activity to dcd1 mutants and leads to an average 17.5-fold overproduction of the enzyme in wild-type cells. The complementing activity of the plasmid was localized to a 4.2-kb PvuII restriction fragment within the Sau3A insert. Subcloning experiments demonstrated that a single HindIII restriction site within this fragment lies within the DCD1 gene. Subsequent DNA sequence analysis revealed a 936-nucleotide open reading frame encompassing this HindIII site. Disruption of the open reading frame by integrative transformation led to a loss of enzyme activity and confirmed that this region constitutes the dCMP deaminase gene. Northern analysis indicated that the DCD1 mRNA is a 1.15-kb poly(A)+ transcript. The 5' end of the transcript was mapped by primer extension and appears to exhibit heterogeneous termini. Comparison of the amino acid sequence of the T2 bacteriophage dCMP deaminase with that deduced for the yeast enzyme revealed a limited degree of homology which extends over the entire length of the phage polypeptide (188 amino acids) but is confined to the carboxy-terminal half of the yeast protein (312 amino acids). A potential dTTP-binding site in the yeast and phage enzymes was identified by comparison of homologous regions with the amino acid sequences of a variety of other dTTP-binding enzymes. Despite the role of dCMP deaminase in dTTP biosynthesis, Northern analysis revealed that the DCD1 gene is not subject to the same cell cycle-dependent pattern of transcription recently found for the yeast thymidylate synthetase gene (TMP1).

Ammonia regulation of amino acid permeases in Saccharomyces cerevisiae

1983 ◽  
Vol 3 (4) ◽  
pp. 672-683
Author(s):  
W E Courchesne ◽  
B Magasanik
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acid ◽  
Cytoplasmic Membrane ◽  
Nitrogen Sources ◽  
Amino Acid Permease ◽  
Inducer Exclusion ◽  
Amino Acid Permeases ◽  
General Amino Acid Permease ◽  
State Growth ◽  
And Control

The activities of the proline-specific permease (PUT4) and the general amino acid permease (GAP1) of Saccharomyces cerevisiae vary 70- to 140-fold in response to the nitrogen source of the growth medium. The PUT4 and GAP1 permease activities are regulated by control of synthesis and control of activity. These permeases are irreversibly inactivated by addition of ammonia or glutamine, lowering the activity to that found during steady-state growth on these nitrogen sources. Mutants altered in the regulation of the PUT4 permease (Per-) have been isolated. The mutations in these strains are pleiotropic and affect many other permeases, but have no direct effect on various cytoplasmic enzymes involved in nitrogen assimilation. In strains having one class of mutations (per1), ammonia inactivation of the PUT4 and GAP1 permeases did not occur, whereas glutamate and glutamine inactivation did. Thus, there appear to be two independent inactivation systems, one responding to ammonia and one responding to glutamate (or a metabolite of glutamate). The mutations were found to be nuclear and recessive. The inactivation systems are constitutive and do not require transport of the effector molecules per se, apparently operating on the inside of the cytoplasmic membrane. The ammonia inactivation was found not to require a functional glutamate dehydrogenase (NADP). These mutants were used to show that ammonia exerts control of arginase synthesis largely by inducer exclusion. This may be the primary mode of nitrogen regulation for most nitrogen-regulated enzymes of S. cerevisiae.

scholarly journals Comparative studies on O-acetylhomoserine sulfhydrylase: physiological role and characterization of the Aspergillus nidulans enzyme.

1993 ◽  
Vol 40 (3) ◽  
pp. 421-428 ◽  
Author(s):  
J Brzywczy ◽  
S Yamagata ◽  
A Paszewski
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Substrate Specificity ◽  
Aspergillus Nidulans ◽  
Comparative Studies ◽  
Alternative Pathway ◽  
Physiological Role ◽  
Oligomeric Protein ◽  
Cysteine Synthesis ◽  
Sulfhydryl Compounds

O-acetylhomoserine sulfhydrylase (OAH SHLase) from Aspergillus nidulans is an oligomeric protein with a broad substrate specificity with regard to sulfhydryl compounds. As its Saccharomyces cerevisiae counterpart the enzyme also reacts with O-acetylserine and is inhibited by carbonyl reagents but not by antiserum raised against the yeast enzyme. In contrast to Saccharomyces cerevisiae the enzyme is not essential for Aspergillus nidulans as indicated by the completely prototrophic phenotype of OAH SHLase-negative mutants. Its major physiological role in Aspergillus nidulans seems to be recycling of the thiomethyl group of methylthio-adenosine but it is also a constituent of the alternative pathway of cysteine synthesis.

scholarly journals Purification of arginase from Aspergillus nidulans.

1994 ◽  
Vol 41 (4) ◽  
pp. 467-471 ◽  
Author(s):  
A Dzikowska ◽  
J P Le Caer ◽  
P Jonczyk ◽  
P Wëgleński
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Neurospora Crassa ◽  
Molecular Mass ◽  
Nitrogen Source ◽  
Aspergillus Nidulans ◽  
Sole Nitrogen Source ◽  
Mass Ratio ◽  
Conserved Domains ◽  
Native Molecular Mass ◽  
High Degree

Arginase (EC 3.5.3.1) of Aspergillus nidulans, the enzyme which enables the fungus to use arginine as the sole nitrogen source was purified to homogeneity. Molecular mass of the purified arginase subunit is 40 kDa and is similar to that reported for the Neurospora crassa (38.3 kDa) and Saccharomyces cerevisiae (39 kDa) enzymes. The native molecular mass of arginase is 125 kDa. The subunit/native molecular mass ratio suggests a trimeric form of the protein. The arginase protein was cleaved and partially sequenced. Two out of the six polypeptides sequenced show a high degree of homology to conserved domains in arginases from other species.

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