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Favilla LD, Herman TS, Goersch CDS, de Andrade RV, Felipe MSS, Bocca AL, Fernandes L. Expanding the Toolbox for Functional Genomics in Fonsecaea pedrosoi: The Use of Split-Marker and Biolistic Transformation for Inactivation of Tryptophan Synthase ( trpB) Gene. J Fungi (Basel) 2023; 9:jof9020224. [PMID: 36836338 PMCID: PMC9963410 DOI: 10.3390/jof9020224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 01/27/2023] [Accepted: 01/31/2023] [Indexed: 02/11/2023] Open
Abstract
Chromoblastomycosis (CBM) is a disease caused by several dematiaceous fungi from different genera, and Fonsecaea is the most common which has been clinically isolated. Genetic transformation methods have recently been described; however, molecular tools for the functional study of genes have been scarcely reported for those fungi. In this work, we demonstrated that gene deletion and generation of the null mutant by homologous recombination are achievable for Fonsecaea pedrosoi by the use of two approaches: use of double-joint PCR for cassette construction, followed by delivery of the split-marker by biolistic transformation. Through in silico analyses, we identified that F. pedrosoi presents the complete enzymatic apparatus required for tryptophan (trp) biosynthesis. The gene encoding a tryptophan synthase trpB -which converts chorismate to trp-was disrupted. The ΔtrpB auxotrophic mutant can grow with external trp supply, but germination, viability of conidia, and radial growth are defective compared to the wild-type and reconstituted strains. The use of 5-FAA for selection of trp- phenotypes and for counter-selection of strains carrying the trp gene was also demonstrated. The molecular tools for the functional study of genes, allied to the genetic information from genomic databases, significantly boost our understanding of the biology and pathogenicity of CBM causative agents.
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Affiliation(s)
- Luísa Dan Favilla
- Laboratory of Applied Immunology, Institute of Biology, Campus Darcy Ribeiro, University of Brasília, Asa Norte, Federal District, Brasilia 70910-900, Brazil
- Graduate Program in Molecular Biology, Institute of Biology, Campus Darcy Ribeiro, University of Brasília, Asa Norte, Federal District, Brasilia 70910-900, Brazil
| | - Tatiana Sobianski Herman
- Laboratory of Applied Immunology, Institute of Biology, Campus Darcy Ribeiro, University of Brasília, Asa Norte, Federal District, Brasilia 70910-900, Brazil
- Graduate Program in Molecular Patology, Faculty of Medicine, Campus Darcy Ribeiro, University of Brasília, Asa Norte, Federal District, Brasilia 70910-900, Brazil
| | - Camila da Silva Goersch
- Laboratory of Applied Immunology, Institute of Biology, Campus Darcy Ribeiro, University of Brasília, Asa Norte, Federal District, Brasilia 70910-900, Brazil
- Graduate Program in Microbial Biology, Institute of Biology, Campus Darcy Ribeiro, University of Brasília, Asa Norte, Federal District, Brasilia 70910-900, Brazil
| | - Rosangela Vieira de Andrade
- Graduate Program of Genomic Sciences and Biotechnology, Catholic University of Brasilia, Campus Asa Norte, Asa Norte, Federal District, Taguatinga 70790-160, Brazil
| | - Maria Sueli Soares Felipe
- Graduate Program of Genomic Sciences and Biotechnology, Catholic University of Brasilia, Campus Asa Norte, Asa Norte, Federal District, Taguatinga 70790-160, Brazil
| | - Anamélia Lorenzetti Bocca
- Laboratory of Applied Immunology, Institute of Biology, Campus Darcy Ribeiro, University of Brasília, Asa Norte, Federal District, Brasilia 70910-900, Brazil
- Graduate Program in Molecular Biology, Institute of Biology, Campus Darcy Ribeiro, University of Brasília, Asa Norte, Federal District, Brasilia 70910-900, Brazil
- Graduate Program in Molecular Patology, Faculty of Medicine, Campus Darcy Ribeiro, University of Brasília, Asa Norte, Federal District, Brasilia 70910-900, Brazil
| | - Larissa Fernandes
- Laboratory of Applied Immunology, Institute of Biology, Campus Darcy Ribeiro, University of Brasília, Asa Norte, Federal District, Brasilia 70910-900, Brazil
- Graduate Program in Microbial Biology, Institute of Biology, Campus Darcy Ribeiro, University of Brasília, Asa Norte, Federal District, Brasilia 70910-900, Brazil
- Centro Metropolitano, Faculty of Ceilândia, Campus UnB Ceilândia, University of Brasília, Ceilândia Sul, Federal District, Brasilia 72220-275, Brazil
- Correspondence:
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2
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Wiest A, Barchers D, Eaton M, Henderson R, Schnittker R, McCluskey K. Molecular analysis of intragenic recombination at the tryptophan synthetase locus in Neurospora crassa. J Genet 2013; 92:523-8. [PMID: 24371173 DOI: 10.1007/s12041-013-0305-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Fifteen different classically generated and mapped mutations at the tryptophan synthetase locus in Neurospora crassa have been characterized to the level of the primary sequence of the gene. This sequence analysis has demonstrated that intragenic recombination is accurate to order mutations within one open reading frame. While classic genetic analysis correctly ordered the mutations, the position of mutations characterized by gene sequence analysis was more accurate. A leaky mutation was found to have a wild-type primary sequence. The presence of unique polymorphisms in the primary sequence of the trp-3 gene from strain 861 confirms that it has a unique history relative to the other strains studied. Most strains that were previously shown to be immunologically nonreactive with antibody preparations raised against tryptophan synthetase protein were shown to have nonsense mutations. This work defines 14 alleles of the N. crassa trp-3 gene.
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Affiliation(s)
- A Wiest
- Fungal Genetics Stock Center, University of Missouri, Kansas City, USA.
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3
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Ireland C, Peekhaus N, Lu P, Sangari R, Zhang A, Masurekar P, An Z. The tryptophan synthetase gene TRP1 of Nodulisporium sp.: molecular characterization and its relation to nodulisporic acid A production. Appl Microbiol Biotechnol 2008; 79:451-9. [PMID: 18389234 DOI: 10.1007/s00253-008-1440-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2007] [Revised: 02/26/2008] [Accepted: 02/29/2008] [Indexed: 10/22/2022]
Abstract
Nodulisporic acid A (NAA), an insecticidal indole diterpene, is produced by the fungus Nodulisporium sp. Since indole-3-glycerolphosphate is the precursor of the indole moiety of NAA, it is suggested that the activity of tryptophan synthetase may play a role in NAA biosynthesis. To investigate this hypothesis, the tryptophan synthetase gene TRP1 of Nodulisporium sp. was cloned and characterized. The gene consists of three introns of 146, 68, and 57 bp. The four exons encode a protein of 712 amino acids, the sequence of which is highly homologous to that of other fungal tryptophan synthetase proteins. The transcription initiation site was mapped 66 bp upstream to the ATG, and the polyA tail attachment site is 169 bp downstream to the translation stop codon. Replacement of the N-terminal half of the gene with a hygromycin selection marker yielded mutants with the tryptophan auxotroph/hygromycin-resistance (trp(-)/hyr) phenotype. The TRP1 mutants required a high concentration of tryptophan supplement in solid medium (10 mM) to sustain minimal growth and failed to produce NAA in the production medium (FFL-CAM) supplemented with high concentrations of tryptophan.
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Affiliation(s)
- C Ireland
- Merck Research Laboratories, PO Box 2000, RY80Y-325, Rahway, NJ 07065, USA
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4
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Miles EW. Structural basis for catalysis by tryptophan synthase. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2006; 64:93-172. [PMID: 2053470 DOI: 10.1002/9780470123102.ch3] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- E W Miles
- Laboratory of Biochemistry and Pharmacology, National Institutes of Health, Bethesda, Maryland
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5
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Kulik V, Hartmann E, Weyand M, Frey M, Gierl A, Niks D, Dunn MF, Schlichting I. On the structural basis of the catalytic mechanism and the regulation of the alpha subunit of tryptophan synthase from Salmonella typhimurium and BX1 from maize, two evolutionarily related enzymes. J Mol Biol 2005; 352:608-20. [PMID: 16120446 DOI: 10.1016/j.jmb.2005.07.014] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2005] [Revised: 07/03/2005] [Accepted: 07/06/2005] [Indexed: 10/25/2022]
Abstract
Indole is a reaction intermediate in at least two biosynthetic pathways in maize seedlings. In the primary metabolism, the alpha-subunit (TSA) of the bifunctional tryptophan synthase (TRPS) catalyzes the cleavage of indole 3-glycerol phosphate (IGP) to indole and d-glyceraldehyde 3-phosphate (G3P). Subsequently, indole diffuses through the connecting tunnel to the beta-active site where it is condensed with serine to form tryptophan and water. The maize enzyme, BX1, a homolog of TSA, also cleaves IGP to G3P and indole, and the indole is further converted to 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one, a secondary plant metabolite. BX1 cleaves IGP significantly faster to G3P and indole than does TSA. In line with their different biological functions, these two evolutionary related enzymes differ significantly in their regulatory aspects while catalyzing the same chemistry. Here, the mechanism of IGP cleavage by TSA was analyzed using a novel transition state analogue generated in situ by reaction of 2-aminophenol and G3P. The crystal structure of the complex shows an sp3-hybridized atom corresponding to the C3 position of IGP. The catalytic alphaGlu49 rotates to interact with the sp3-hybridized atom and the 3' hydroxyl group suggesting that it serves both as proton donor and acceptor in the alpha-reaction. The second catalytic residue, alphaAsp60 interacts with the atom corresponding to the indolyl nitrogen, and the catalytically important loop alphaL6 is in the closed, high activity conformation. Comparison of the TSA and TSA-transition state analogue structures with the crystal structure of BX1 suggests that the faster catalytic rate of BX1 may be due to a stabilization of the active conformation: loop alphaL6 is closed and the catalytic glutamate is in the active conformation. The latter is caused by a substitution of the residues that stabilize the inactive conformation in TRPS.
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Affiliation(s)
- Victor Kulik
- Max Planck Institut fur medizinische Forschung, Abteilung fur Biomolekulare Mechanismen, Jahnstr. 29, 69120 Heidelberg, Germany
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6
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Palombella AL, Dutcher SK. Identification of the gene encoding the tryptophan synthase beta-subunit from Chlamydomonas reinhardtii. PLANT PHYSIOLOGY 1998; 117:455-64. [PMID: 9625698 PMCID: PMC34965 DOI: 10.1104/pp.117.2.455] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/1997] [Accepted: 02/24/1998] [Indexed: 05/22/2023]
Abstract
We report the isolation of a Chlamydomonas reinhardtii cDNA that encodes the beta-subunit of tryptophan synthase (TSB). This cDNA was cloned by functional complementation of a trp-operon-deleted strain of Escherichia coli. Hybridization analysis indicated that the gene exists in a single copy. The predicted amino acid sequence showed the greatest identity to TSB polypeptides from other photosynthetic organisms. With the goal of identifying mutations in the gene encoding this enzyme, we isolated 11 recessive and 1 dominant single-gene mutation that conferred resistance to 5-fluoroindole. These mutations fell into three complementation groups, MAA2, MAA7, and TAR1. In vitro assays showed that mutations at each of these loci affected TSB activity. Restriction fragment-length polymorphism analysis suggested that MAA7 encodes TSB. MAA2 and TAR1 may act to regulate the activity of MAA7 or its protein product.
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Affiliation(s)
- A L Palombella
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309-0347, USA
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7
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Schwarz T, Uthoff K, Klinger C, Meyer HE, Bartholmes P, Kaufmann M. Multifunctional tryptophan-synthesizing enzyme. The molecular weight of the Euglena gracilis protein is unexpectedly low. J Biol Chem 1997; 272:10616-23. [PMID: 9099709 DOI: 10.1074/jbc.272.16.10616] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
After developing a suitable procedure to produce large amounts of Euglena gracilis as well as a reliable protocol to purify the multifunctional tryptophan-synthesizing enzyme derived from it (Schwarz, T., Bartholmes, P., and Kaufmann, M. (1995) Biotechnol. Appl. Biochem. 22, 179-190), we here describe structural and catalytic properties of the multifunctional tryptophan-synthesizing enzyme. The kinetic parameters kcat of all five activities and Km for the main substrates were determined. The relative molecular weight under denaturing conditions as judged by SDS-polyacrylamide gel electrophoresis is 136,000. Cross-linking as well as gel filtration experiments revealed that the enzyme exists as a homodimer. Neither intersubunit disulfide linkages nor glycosylations were detected. On the other hand, the polypeptide chains are blocked N-terminally. Complete tryptic digestion of the protomer, high pressure liquid chromatography separation of the resulting peptides, and N-terminal sequence analysis of homogenous peaks as judged by matrix-assisted laser/desorption ionization time-of-flight mass spectrometry was performed. Depending on the sequenced peptides, alignments to all entries of the SwissProt data base resulted in both strong sequence homologies to known Trp sequences and no similarities at all. Proteolytic digestion under native conditions using endoproteinase Glu-C uncovered one major cleavage site yielding a semistable, N-terminally blocked fragment with a molecular weight of 119,000. In addition, an increase in beta-elimination accompanied by a decrease in beta-replacement activity of the beta-reaction during proteolysis was observed.
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Affiliation(s)
- T Schwarz
- Institut für Biochemie, Universität Witten, Herdecke, Stockumer Str. 10, 58453 Witten, Germany
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8
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Yee MC, Horn V, Yanofsky C. On the role of helix 0 of the tryptophan synthetase alpha chain of Escherichia coli. J Biol Chem 1996; 271:14754-63. [PMID: 8662916 DOI: 10.1074/jbc.271.25.14754] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The role of helix 0 of the alpha chain (TrpA) of the tryptophan synthetase alpha2beta2 multi-functional enzyme complex of Escherichia coli was examined by deleting amino-terminal residues 2-6, 2-11, or 2-19 of TrpA. Selected substitutions were also introduced at TrpA positions 2-6. The altered genes encoding these polypeptides were overexpressed from a foreign promoter on a multicopy plasmid and following insertion at their normal chromosomal location. Each deletion polypeptide was functional in vivo. However all appeared to be somewhat more labile and insoluble and less active enzymatically than wild type TrpA. The deletion polypeptides were overproduced and solubilized from cell debris by denaturation and refolding. Several were partially purified and assayed in various reactions in the presence of tryptophan synthetase beta2 (TrpB). The purified TrpADelta2-6 and TrpADelta2-11 deletion polypeptides had low activity in both the indole + serine --> tryptophan reaction and the indoleglycerol phosphate + serine --> tryptophan reaction. Poor activity in each reaction was partly due to reduced association of TrpA with TrpB. The addition of the TrpA ligands, alpha-glycerophosphate or indoleglycerol phosphate, during catalysis of the indole + serine --> tryptophan reaction increased association and activity. These findings suggest that removal of helix 0 of TrpA decreases TrpA-TrpB association as well as the activity of the TrpA active site. Alignment of the TrpA sequences from different species indicates that several lack part or all of helix 0. In some of these polypeptides, extra residues at the carboxyl end may substitute for helix 0.
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Affiliation(s)
- M C Yee
- Department of Biological Sciences, Stanford University, Stanford, California, 94305-5020, USA
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9
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Radwanski ER, Zhao J, Last RL. Arabidopsis thaliana tryptophan synthase alpha: gene cloning, expression, and subunit interaction. MOLECULAR & GENERAL GENETICS : MGG 1995; 248:657-67. [PMID: 7476868 DOI: 10.1007/bf02191705] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The tryptophan synthase alpha subunit catalyzes the conversion of indole-3-glycerolphosphate to indole, the penultimate reaction in the biosynthesis of the essential amino acid tryptophan. A cDNA encoding Arabidopsis thaliana tryptophan synthase alpha(TSA1) was isolated by complementation of an Escherichia coli delta trpA mutation and by polymerase chain reaction amplification from a cDNA library using degenerate primers. A TSA1 genomic clone was also isolated and 5 kb of the DNA sequence determined. A single sequence in the Arabidopsis genome with homology to the TSA1 cDNA was detected by high-stringency genomic Southern blot hybridization. In contrast under hybridization conditions of reduced stringency, one or two additional homologous sequences were observed. A 1.4 kb transcript was detected in wild-type RNA with the TSA1 cDNA as a probe. Several lines of evidence, including immunoaffinity chromatography, suggest that the active A. thaliana tryptophan synthase enzyme consists of a heterosubunit complex, presumably analogous to the prokaryotic alpha 2 beta 2 complex. Immunoblot analysis indicated that the plant alpha and beta subunits are present throughout development.
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Affiliation(s)
- E R Radwanski
- Boyce Thompson Institute for Plant Research, Cornell University, Ithaca, NY 14853-1801, USA
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10
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Davis CR, McPeek MA, McClung CR. Molecular characterization of the proline-1 (pro-1) locus of Neurospora crassa, which encodes delta 1-pyrroline-5-carboxylate reductase. MOLECULAR & GENERAL GENETICS : MGG 1995; 248:341-50. [PMID: 7565596 DOI: 10.1007/bf02191601] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
delta 1-pyrroline-5-carboxylate reductase (P5CR; [L-proline: NAD(P+) 5-oxidoreductase]; EC 1.5.1.2) catalyzes the final step in proline biosynthesis. We have shown that the proline-1 (pro-1) locus of Neurospora crassa encodes P5CR. The pro-1 gene was localized to a 3.2 kb region by complementation of (restoration of proline-independent growth to) a proline auxotroph carrying a recessive mutation at the pro-1 locus. The nucleotide sequence of this 3.2 kb region contains an open reading frame with coding capacity of 311 amino acids. The deduced polypeptide shows significant similarity to P5CR amino acid sequences. Similarity of N. crassa P5CR is greatest to that of the yeast, Saccharomyces cerevisiae, but is also strong to P5CR sequences from archaea, eubacteria, plants, and humans. In N. crassa, amino acid imbalance, including deficiency or excess of a single amino acid, such as histidine, induces expression of many amino acid biosynthetic genes that are under cross-pathway control, a general regulatory system analogous to general amino acid control in Saccharomyces. Although P5CR catalyzes the only committed step in proline biosynthesis, pro-1 expression was unaltered by histidine starvation and independent of CPC1, a positively acting transcription factor that mediates cross-pathway control in N. crassa.
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Affiliation(s)
- C R Davis
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755, USA
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11
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Fosså A, Beyer A, Pfitzner E, Wenzel B, Kunau WH. Molecular cloning, sequencing and sequence analysis of the fox-2 gene of Neurospora crassa encoding the multifunctional beta-oxidation protein. MOLECULAR & GENERAL GENETICS : MGG 1995; 247:95-104. [PMID: 7715608 DOI: 10.1007/bf00425825] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We present the molecular cloning and sequencing of genomic and cDNA clones of the fox-2 gene of Neurospora crassa, encoding the multifunctional beta-oxidation protein (MFP). The coding region of the fox-2 gene is interrupted by three introns, one of which appears to be inefficiently spliced out. The encoded protein comprises 894 amino acid residues and exhibits 45% and 47% sequence identity with the MFPs of Candida tropicalis and Saccharomyces cerevisiae, respectively. Sequence analysis identifies three regions of the fungal MFPs that are highly conserved. These regions are separated by two segments that resemble linkers between domains of other MFPs, suggesting a three-domain structure. The first and second conserved regions of each MFP are homologous to each other and to members of the short-chain alcohol dehydrogenase family. We discuss these homologies in view of recent findings that fungal MFPs contain enoyl-CoA hydratase 2 and D-3-hydroxyacyl-CoA dehydrogenase activities, converting trans-2-enoyl-CoA via D-3-hydroxyacyl-CoA to 3-ketoacyl-CoA. In contrast to its counterparts in yeasts, the Neurospora MFP does not have a C-terminal sequence resembling the SKL motif involved in protein targeting to microbodies.
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Affiliation(s)
- A Fosså
- Institut für Physiologische Chemie, Abteilung für Zellbiochemie, Ruhr-Universität Bochum, Germany
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12
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Glass NL, Donaldson GC. Development of primer sets designed for use with the PCR to amplify conserved genes from filamentous ascomycetes. Appl Environ Microbiol 1995; 61:1323-30. [PMID: 7747954 PMCID: PMC167388 DOI: 10.1128/aem.61.4.1323-1330.1995] [Citation(s) in RCA: 2249] [Impact Index Per Article: 77.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
We constructed nine sets of oligonucleotide primers on the basis of the results of DNA hybridization of cloned genes from Neurospora crassa and Aspergillus nidulans to the genomes of select filamentous ascomycetes and deuteromycetes (with filamentous ascomycete affiliations). Nine sets of primers were designed to amplify segments of DNA that span one or more introns in conserved genes. PCR DNA amplification with the nine primer sets with genomic DNA from ascomycetes, deuteromycetes, basidiomycetes, and plants revealed that five of the primer sets amplified a product only from DNA of the filamentous ascomycetes and deuteromycetes. The five primer sets were constructed from the N. crassa genes for histone 3, histone 4, beta-tubulin, and the plasma membrane ATPase. With these five primer sets, polymorphisms were observed in both the size of and restriction enzyme sites in the amplified products from the filamentous ascomycetes. The primer sets described here may provide useful tools for phylogenetic studies and genome analyses in filamentous ascomycetes and deuteromycetes (with ascomycete affiliations), as well as for the rapid differentiation of fungal species by PCR.
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Affiliation(s)
- N L Glass
- Botany Department, University of British Columbia, Vancouver, Canada
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13
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Tamaru H, Nishida T, Harashima T, Inoue H. Transcriptional activation of a cycloheximide-inducible gene encoding laccase is mediated by cpc-1, the cross-pathway control gene, in Neurospora crassa. MOLECULAR & GENERAL GENETICS : MGG 1994; 243:548-54. [PMID: 8208246 DOI: 10.1007/bf00284203] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Expression of the laccase gene (lacc) of Neurospora crassa is transcriptionally inducible by the protein synthesis inhibitor cycloheximide. A lni-1 mutation, conferring the laccase non-inducible phenotype, was found to be a cpc-1 allele. Northern blots probed with plasmid pLA1, which carries the lacc gene revealed that the cpc-1 mutation abolishes the induced transcription of the lacc gene, indicating requirement of the cpc-1 gene for transcriptional activation of the lacc gene. In Northern blots probed with plasmid pAB1, which bears arg-2 a gene whose transcription is under the control of CPC1, the level of the arg-2 transcript was shown to increase several-fold in wild-type mycelia but remained low in cpc-1 mycelia, after treatment with cycloheximide. This suggests that inhibition of protein synthesis with cycloheximide, as well as amino acid limitation, elicits the CPC1-mediated cross-pathway control. Characterization of the lacc upstream region using a series of 5'-deletion plasmids led to the identification of a 170 bp DNA region required for the induced lacc expression. Sequence analysis of this DNA region demonstrated that it includes a 9 bp sequence with dyad symmetry, ATGAATCAT, which differs only by a central base pair from ATGA(C/G)TCAT, the recognition sequence characteristic of CPC1 and GCN4 binding sites. Possible mechanisms by which CPC1 mediates transcriptional activation of the lacc gene are discussed.
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Affiliation(s)
- H Tamaru
- Department of Regulation Biology, Faculty of Science, Saitama University, Urawa, Japan
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14
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Edwards CJ, Innes DJ, Burns DM, Beacham IR. UDP-sugar hydrolase isozymes in Salmonella enterica and Escherichia coli: silent alleles of ushA in related strains of group I Salmonella isolates, and of ushB in wild-type and K12 strains of E. coli, indicate recent and early silencing events, respectively. FEMS Microbiol Lett 1993; 114:293-8. [PMID: 8288106 DOI: 10.1111/j.1574-6968.1993.tb06588.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Escherichia coli contains a single periplasmic UDP-glucose hydrolase (5'-nucleotidase) encoded by ushA. Salmonella enterica, serotype Typhimurium, also contains a single UDP-glucose hydrolase but, in contrast to E. coli, it is membrane-bound and is encoded by the non-homologous ushB gene; Salmonella enterica (Typhimurium) also contains a silent allele of the ushA gene (ushA0). In this report, we show that nearly all natural isolates of Salmonella contain both UDP-sugar hydrolases, i.e. they are UshA+ UshB+. The only exceptions are all from sub-group I (S. gallinarum, S. pullorum, and most Typhimurium strains), are UshA- UshB+, and several have been shown to contain an ushA0 allele. These data, together with the fact that these latter strains are closely related genetically, strongly suggests a recent silencing mutation(s). We also report the presence in E. coli K-12, and in natural isolates of E. coli, of a DNA sequence which is homologous to the ushB gene of Salmonella; since E. coli does not contain UshB activity, we tentatively refer to this sequence as ushB0. Since all E. coli strains investigated are UshB-, we conclude that the silencing mutation(s) occurred relatively early following the divergence of Escherichia coli and Salmonella from a common ancestor that was ushA+ ushB+.
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Affiliation(s)
- C J Edwards
- Faculty of Science and Technology, Griffith University, Brisbane, Queensland, Australia
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15
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Yang X, Miles E. A novel intersubunit repair mechanism in the tryptophan synthase alpha 2 beta 2 complex. Critical role of the beta subunit lysine 167 in intersubunit communication. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(18)41523-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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16
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Valentin K, Kostrzewa M, Zetsche K. Glutamate synthase is plastid-encoded in a red alga: implications for the evolution of glutamate synthases. PLANT MOLECULAR BIOLOGY 1993; 23:77-85. [PMID: 8219058 DOI: 10.1007/bf00021421] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
An actively transcribed gene (glsF) encoding for ferredoxin-dependent glutamate synthase (Fd-GOGAT) was found on the plastid genome of the multicellular red alga Antithamnion sp. Fd-GOGAT is not plastid-encoded in chlorophytic plants, demonstrating that red algal plastid genomes encode for additional functions when compared to those known from green chloroplasts. Moreover, our results suggest that the plant Fd-GOGAT has an endosymbiotic origin. The same may not be true for NADPH-dependent GOGAT. In Antithamnion glsF is flanked upstream by cpcBA and downstream by psaC and is transcribed monocistronically. Implications of these results for the evolution of GOGAT enzymes and the plastid genome are discussed.
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Affiliation(s)
- K Valentin
- Institute for Plant Physiology, Giessen, Germany
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Zhao GP, Somerville RL. Genetic and biochemical characterization of the trpB8 mutation of Escherichia coli tryptophan synthase. An amino acid switch at the sharp turn of the trypsin-sensitive "hinge" region diminishes substrate binding and alters solubility. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)48527-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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18
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Sachs MS, Yanofsky C. Developmental expression of genes involved in conidiation and amino acid biosynthesis in Neurospora crassa. Dev Biol 1991; 148:117-28. [PMID: 1834495 DOI: 10.1016/0012-1606(91)90322-t] [Citation(s) in RCA: 89] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The levels of transcripts for Neurospora crassa genes concerned with cellular and metabolic functions changed dramatically at different stages of asexual development. Transcripts for some conidiation-related (con) genes were present at high levels in conidiating cultures and in dormant conidia, but were absent or reduced during mycelial growth. Levels of some con transcripts increased transiently during conidial germination, while others disappeared. Transcripts for amino acid biosynthetic enzymes, ribosomal proteins, cytochrome oxidase subunits, histones, and other polypeptides important for cell growth were detected in newly formed conidia and were present at reduced levels in dormant conidia. Levels of these transcripts increased upon germination of wild-type conidia in minimal medium, reaching their highest levels during this stage or during the early phase of exponential growth. The increased transcription of amino acid biosynthetic genes observed during germination in minimal medium was not dependent on a functional cpc-1 gene. However, cpc-1, which encodes a DNA binding protein presumed to function as a transcriptional activator, was essential for increased expression of amino acid biosynthetic genes when amino acid starvation was imposed during germination or at any subsequent stage of mycelial growth.
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Affiliation(s)
- M S Sachs
- Department of Biological Sciences, Stanford University, California 94305
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19
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Braus GH. Aromatic amino acid biosynthesis in the yeast Saccharomyces cerevisiae: a model system for the regulation of a eukaryotic biosynthetic pathway. Microbiol Rev 1991; 55:349-70. [PMID: 1943992 PMCID: PMC372824 DOI: 10.1128/mr.55.3.349-370.1991] [Citation(s) in RCA: 124] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
This review focuses on the gene-enzyme relationships and the regulation of different levels of the aromatic amino acid biosynthetic pathway in a simple eukaryotic system, the unicellular yeast Saccharomyces cerevisiae. Most reactions of this branched pathway are common to all organisms which are able to synthesize tryptophan, phenylalanine, and tyrosine. The current knowledge about the two main control mechanisms of the yeast aromatic amino acid biosynthesis is reviewed. (i) At the transcriptional level, most structural genes are regulated by the transcriptional activator GCN4, the regulator of the general amino acid control network, which couples transcriptional derepression to amino acid starvation of numerous structural genes in multiple amino acid biosynthetic pathways. (ii) At the enzyme level, the carbon flow is controlled mainly by modulating the enzyme activities at the first step of the pathway and at the branch points by feedback action of the three aromatic amino acid end products. Implications of these findings for the relationship of S. cerevisiae to prokaryotic as well as to higher eukaryotic organisms and for general regulatory mechanisms occurring in a living cell such as initiation of transcription, enzyme regulation, and the regulation of a metabolic branch point are discussed.
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Affiliation(s)
- G H Braus
- Mikrobiologisches Institut, Eidgenössische Technische Hochschule Zürich, CH-8092, Switzerland
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20
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Burns DM, Horn V, Paluh J, Yanofsky C. Evolution of the tryptophan synthetase of fungi. Analysis of experimentally fused Escherichia coli tryptophan synthetase alpha and beta chains. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(19)39940-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Affiliation(s)
- R Bentley
- Department of Chemistry, University of Sheffield, U.K
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22
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Skrzynia C, Binninger DM, Alspaugh JA, Pukkila PJ. Molecular characterization of TRP1, a gene coding for tryptophan synthetase in the basidiomycete Coprinus cinereus. Gene X 1989; 81:73-82. [PMID: 2806911 DOI: 10.1016/0378-1119(89)90338-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
We utilized a cloned gene (TRP5) encoding tryptophan synthetase (TSase) from Saccharomyces cerevisiae to identify and clone the corresponding gene (TRP1) from the basidiomycete Coprinus cinereus. The primary nucleotide (nt) sequence of this gene was determined and compared to sequences from other filamentous fungi, as well as to other genes coding for TSase. A transformation assay was used to demonstrate that 321 nt, which do not include CAAT or TATAAA elements and precede the translation initiation codon, are sufficient for expression in a variety of chromosomal locations. The coding region (2584 nt) is interrupted at nine positions, and putative splicing signals (5'-GTRNGT...YAG-3') are present in each case. The predicted translation product contains 702 amino acids (aa) and is very similar to other TSases, except in the region of aa 257-296 that connects the alpha and beta functional domains. Both the number and the identity of the aa differ in this region between C. cinereus. S. cerevisiae, and Neurospora crassa. Comparison of exon boundaries in the C. cinereus sequence to the three-dimensional structure of Salmonella typhimurium TSase indicates that there is no simple correlation between exons and major functional domains in this protein.
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Affiliation(s)
- C Skrzynia
- Department of Biology and Curriculum in Genetics, University of North Carolina, Chapel Hill 27599-3280
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