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Rollero S, Mouret JR, Bloem A, Sanchez I, Ortiz-Julien A, Sablayrolles JM, Dequin S, Camarasa C. Quantitative 13 C-isotope labelling-based analysis to elucidate the influence of environmental parameters on the production of fermentative aromas during wine fermentation. Microb Biotechnol 2017; 10:1649-1662. [PMID: 28695583 PMCID: PMC5658611 DOI: 10.1111/1751-7915.12749] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 04/28/2017] [Accepted: 05/24/2017] [Indexed: 02/02/2023] Open
Abstract
Nitrogen and lipids are key nutrients of grape must that influence the production of fermentative aromas by wine yeast, and we have previously shown that a strong interaction exists between these two nutrients. However, more than 90% of the acids and higher alcohols (and their acetate ester derivatives) were derived from intermediates produced by the carbon central metabolism (CCM). The objective of this study was to determine how variations in nitrogen and lipid resources can modulate the contribution of nitrogen and carbon metabolisms for the production of fermentative aromas. A quantitative analysis of metabolism using 13C‐labelled leucine and valine showed that nitrogen availability affected the part of the catabolism of N‐containing compounds, the formation of α‐ketoacids from CCM and the redistribution of fluxes around these precursors, explaining the optimum production of higher alcohols occurring at an intermediate nitrogen content. Moreover, nitrogen content modulated the total production of acids and higher alcohols differently, through variations in the redox state of cells. We also demonstrated that the phytosterol content, modifying the intracellular availability of acetyl‐CoA, can influence the flux distribution, especially the formation of higher alcohols and the conversion of α‐ketoisovalerate to α‐ketoisocaproate.
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Affiliation(s)
- Stéphanie Rollero
- UMR SPO: INRA, Universite Montpellier, Montpellier SupAgro, 34060, Montpellier, France.,Lallemand SAS, 31700, Blagnac, France
| | - Jean-Roch Mouret
- UMR SPO: INRA, Universite Montpellier, Montpellier SupAgro, 34060, Montpellier, France
| | - Audrey Bloem
- UMR SPO: INRA, Universite Montpellier, Montpellier SupAgro, 34060, Montpellier, France
| | - Isabelle Sanchez
- UMR SPO: INRA, Universite Montpellier, Montpellier SupAgro, 34060, Montpellier, France
| | | | | | - Sylvie Dequin
- UMR SPO: INRA, Universite Montpellier, Montpellier SupAgro, 34060, Montpellier, France
| | - Carole Camarasa
- UMR SPO: INRA, Universite Montpellier, Montpellier SupAgro, 34060, Montpellier, France
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Teixeira V, Medeiros TC, Vilaça R, Ferreira J, Moradas-Ferreira P, Costa V. Ceramide signaling targets the PP2A-like protein phosphatase Sit4p to impair vacuolar function, vesicular trafficking and autophagy in Isc1p deficient cells. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1861:21-33. [PMID: 26477382 DOI: 10.1016/j.bbalip.2015.10.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Revised: 09/09/2015] [Accepted: 10/14/2015] [Indexed: 02/02/2023]
Abstract
The vacuoles play important roles in cellular homeostasis and their functions include the digestion of cytoplasmic material and organelles derived from autophagy. Conserved nutrient signaling pathways regulate vacuolar function and autophagy, ensuring normal cell and organismal development and aging. Recent evidence implicates sphingolipids in the modulation of these processes, but the impact of ceramide signaling on vacuolar dynamics and autophagy remains largely unknown. Here, we show that yeast cells lacking Isc1p, an orthologue of mammalian neutral sphingomyelinase type 2, exhibit vacuolar fragmentation and dysfunctions, namely decreased Pep4p-mediated proteolysis and V-ATPase activity, which impairs vacuolar acidification. Moreover, these phenotypes are suppressed by downregulation of the ceramide-activated protein phosphatase Sit4p. The isc1Δ cells also exhibit defective Cvt and vesicular trafficking in a Sit4p-dependent manner, ultimately contributing to a reduced autophagic flux. Importantly, these phenotypes are also suppressed by downregulation of the nutrient signaling kinase TORC1, which is known to inhibit Sit4p and autophagy, or Sch9p. These results support a model in which Sit4p functions downstream of Isc1p in a TORC1-independent, ceramide-dependent signaling branch that impairs vacuolar function and vesicular trafficking, leading to autophagic defects in yeast.
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Affiliation(s)
- Vitor Teixeira
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen s/n, 4200-135 Porto, Portugal; IBMC, Instituto de Biologia Molecular e Celular, Rua do Campo Alegre, 823, 4150-180 Porto, Portugal; ICBAS, Instituto de Ciências Biomédicas Abel Salazar, Departamento de Biologia Molecular, Universidade do Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
| | - Tânia C Medeiros
- IBMC, Instituto de Biologia Molecular e Celular, Rua do Campo Alegre, 823, 4150-180 Porto, Portugal
| | - Rita Vilaça
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen s/n, 4200-135 Porto, Portugal; IBMC, Instituto de Biologia Molecular e Celular, Rua do Campo Alegre, 823, 4150-180 Porto, Portugal
| | - João Ferreira
- IBMC, Instituto de Biologia Molecular e Celular, Rua do Campo Alegre, 823, 4150-180 Porto, Portugal
| | - Pedro Moradas-Ferreira
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen s/n, 4200-135 Porto, Portugal; IBMC, Instituto de Biologia Molecular e Celular, Rua do Campo Alegre, 823, 4150-180 Porto, Portugal; ICBAS, Instituto de Ciências Biomédicas Abel Salazar, Departamento de Biologia Molecular, Universidade do Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
| | - Vítor Costa
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen s/n, 4200-135 Porto, Portugal; IBMC, Instituto de Biologia Molecular e Celular, Rua do Campo Alegre, 823, 4150-180 Porto, Portugal; ICBAS, Instituto de Ciências Biomédicas Abel Salazar, Departamento de Biologia Molecular, Universidade do Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
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Kovaleva GY, Bazykin GA, Brudno M, Gelfand MS. Comparative genomics of transcriptional regulation in yeasts and its application to identification of a candidate alpha-isopropylmalate transporter. J Bioinform Comput Biol 2007; 4:981-98. [PMID: 17099937 DOI: 10.1142/s0219720006002284] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2006] [Revised: 05/17/2006] [Accepted: 06/21/2006] [Indexed: 01/14/2023]
Abstract
Conservation rates in non-protein-coding regions of five yeast genomes of the genus Saccharomyces were analyzed using multiple whole-genome alignments. This analysis confirmed previously shown decrease in conservation rates observed immediately upstream of the translation start point and downstream of the stop-codon. Further, there was a sharp conservation peak in the upstream regions likely related to the core promoter (-35 bp to +35 bp around TSS) and a conservation peak downstream of the stop-codon whose function is not yet clear. Regulation of leucine and methionine biosynthesis controlled by the global regulator Gcn4p and pathway-specific regulators was analyzed in detail. A candidate alpha-isopropylmalate carrier, YOR271cp, was identified based on conservation of Leu3p binding sites, analysis of ChIP-chip data, protein localization and sequence similarity.
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Affiliation(s)
- Galina Yu Kovaleva
- Department of Bioengineering and Bioinformatics, Moscow State University, Moscow, Russia.
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Davis CA, Ares M. Accumulation of unstable promoter-associated transcripts upon loss of the nuclear exosome subunit Rrp6p in Saccharomyces cerevisiae. Proc Natl Acad Sci U S A 2006; 103:3262-7. [PMID: 16484372 PMCID: PMC1413877 DOI: 10.1073/pnas.0507783103] [Citation(s) in RCA: 188] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mutations in RRP6 result in the accumulation of aberrant polyadenylated transcripts from small nucleolar RNA genes. We exploited this observation to search for novel noncoding RNA genes in the yeast genome. When RNA from rrp6Delta yeast is compared with wild-type on whole-genome microarrays, numerous intergenic loci exhibit an increased mutant/wild type signal ratio. Among these loci, we found one encoding a new C/D box small nucleolar RNA, as well as a surprising number that gave rise to heterogeneous Trf4p-polyadenylated RNAs with lengths of approximately 250-500 nt. This class of RNAs is not easily detected in wild-type cells and appears associated with promoters. Fine mapping of several such transcripts shows they originate near known promoter elements but do not usually extend far enough to act as mRNAs, and may regulate the transcription of downstream mRNAs. Rather than being uninformative transcriptional "noise," we hypothesize that these transcripts reflect important features of RNA polymerase activity at the promoter. This activity is normally undetectable in wild-type cells because the transcripts are somehow distinguished from true mRNAs and are degraded in an Rrp6p-dependent fashion in the nucleus.
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Affiliation(s)
- Carrie Anne Davis
- Center for Molecular Biology of RNA, Department of Molecular, Cell, and Developmental Biology, Sinsheimer Laboratories, University of California, Santa Cruz, CA 95064
| | - Manuel Ares
- Center for Molecular Biology of RNA, Department of Molecular, Cell, and Developmental Biology, Sinsheimer Laboratories, University of California, Santa Cruz, CA 95064
- *To whom correspondence should be addressed. E-mail:
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Boer VM, Daran JM, Almering MJH, de Winde JH, Pronk JT. Contribution of the Saccharomyces cerevisiae transcriptional regulator Leu3p to physiology and gene expression in nitrogen- and carbon-limited chemostat cultures. FEMS Yeast Res 2005; 5:885-97. [PMID: 15949974 DOI: 10.1016/j.femsyr.2005.04.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2005] [Revised: 03/23/2005] [Accepted: 04/04/2005] [Indexed: 11/19/2022] Open
Abstract
Transcriptional regulation of branched-chain amino-acid metabolism in Saccharomyces cerevisiae involves two key regulator proteins, Leu3p and Gcn4p. Leu3p is a pathway-specific regulator, known to regulate six genes involved in branched-chain amino-acid metabolism and one gene in nitrogen assimilation. Gcn4p is a global regulator, involved in the general response to amino-acid and purine starvation. To investigate the contribution of Leu3p in regulation of gene expression, a leu3Delta strain was compared to an isogenic reference strain using DNA-microarray analysis. This comparison was performed for both glucose-grown/ammonium-limited and ethanol-limited/ammonium-excess chemostat cultures. In ethanol-limited cultures, absence of Leu3p led to reduced transcript levels of six of the seven established Leu3p target genes, but did not affect key physiological parameters. In ammonium-limited cultures, absence of Leu3p caused a drastic decrease in storage carbohydrate content. mRNA levels of genes involved in storage carbohydrate metabolism were also found reduced. Under N-limited conditions, the leu3Delta genotype elicited an amino-acid starvation response, leading to increased transcript levels of many amino-acid biosynthesis genes. By combining the transcriptome data with data from earlier studies that measured DNA binding of Leu3p both in vitro and in vivo, BAT1, GAT1 and OAC1 were identified as additional Leu3p-regulated genes. This study demonstrates that unravelling of transcriptional regulation networks should preferably include several cultivation conditions and requires a combination of experimental approaches.
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Affiliation(s)
- Viktor M Boer
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands
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Bardazzi I, Casalone E. Construction of two new vectors for transformation of laboratory, natural and industrial Saccharomyces cerevisiae strains to trifluoroleucine and G418 resistance. Folia Microbiol (Praha) 2005; 49:534-8. [PMID: 15702541 DOI: 10.1007/bf02931529] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Two new plasmids, pEC3 and pECkan, were constructed and their use in yeast transformation described. Both plasmids are derivative of the pRS416 vector, in which the URA3 auxotrophic marker was replaced by the LEU4* gene (pEC3) or the kanMX4 gene (pECkan). pEC3 and pECkan plasmids transformed natural and commercial Saccharomyces cerevisiae strains to 5,5,5-trifluoro-DL-leucine and G418 (aminoglycoside related to gentamicin) resistance, respectively, with efficiency ranging from 10(-5) to 10(-7) transformants per number of viable cells. pEC3 transformed the Leu- laboratory strain, carrying the mutations leu4 leu9, to leucine prototrophy with efficiency of approximately 10(-4).
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Affiliation(s)
- I Bardazzi
- Dipartimento di Biologia Animale e Genetica Leo Pardi, Università degli Studi di Firenze, 501 25 Firenze, Italy
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Kohlhaw GB. Leucine biosynthesis in fungi: entering metabolism through the back door. Microbiol Mol Biol Rev 2003; 67:1-15, table of contents. [PMID: 12626680 PMCID: PMC150519 DOI: 10.1128/mmbr.67.1.1-15.2003] [Citation(s) in RCA: 184] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
After exploring evolutionary aspects of branched-chain amino acid biosynthesis, the review focuses on the extended leucine biosynthetic pathway as it operates in Saccharomyces cerevisiae. First, the genes and enzymes specific for the leucine pathway are considered: LEU4 and LEU9 (encoding the alpha-isopropylmalate synthase isoenzymes), LEU1 (isopropylmalate isomerase), and LEU2 (beta-isopropylmalate dehydrogenase). Emphasis is given to the unusual distribution of the branched-chain amino acid pathway enzymes between mitochondrial matrix and cytosol, on the newly defined role of Leu5p, and on regulatory mechanisms governing gene expression and enzyme activity, including new evidence for the metabolic importance of the regulation of alpha-isopropylmalate synthase by coenzyme A. Next, structure-function relationships of the transcriptional regulator Leu3p are addressed, defining its dual role as activator and repressor and discussing evidence in support of the self-masking model. Recent data pointing at a more extended Leu3p regulon are discussed. An overview of the layered controls of the extended leucine pathway is provided that includes a description of the newly recognized roles of Ilv5p and Bat1p in maintaining mitochondrial integrity. Finally, branched-chain amino acid biosynthesis and its regulation in other fungi are summarized, the question of leucine as metabolic signal is addressed, and possible directions of future research in this area are outlined.
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Affiliation(s)
- Gunter B Kohlhaw
- Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907, USA.
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Wang D, Zheng F, Holmberg S, Kohlhaw GB. Yeast transcriptional regulator Leu3p. Self-masking, specificity of masking, and evidence for regulation by the intracellular level of Leu3p. J Biol Chem 1999; 274:19017-24. [PMID: 10383402 DOI: 10.1074/jbc.274.27.19017] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Recent work suggests that the masking of the activation domain (AD) of yeast transactivator Leu3p, observed in the absence of the metabolic signal alpha-isopropylmalate, is an intramolecular event. Much of the evidence came from the construction and analysis of a mutant form of Leu3p (Leu3-dd) whose AD is permanently masked (Wang, D., Hu, Y., Zheng, F., Zhou, K., and Kohlhaw, G. B. (1997) J. Biol. Chem. 272, 19383-19392). In a modified two-hybrid experiment, the ADs of both wild type Leu3p and Leu3-dd were shown to interact with the remainder of the Leu3 protein, in an alpha-isopropylmalate-dependent manner. The finding that masking and unmasking proceed apparently normally when full-length Leu3p is expressed in mammalian cells is also consistent with the notion of intramolecular masking. Here we report on the identification of nine missense mutations (all of them suppressors of the Leu3-dd phenotype) that cause permanent unmasking of Leu3p. The nine mutations map to three short segments located within a 140-residue-long region of the C-terminal part of the middle region of Leu3p. These segments may be part of a spatial trap for the AD. We also performed "domain swaps" between Leu3p and Cha4p, a serine/threonine-responsive activator that, like Leu3p, belongs to the family of Zn(II)2Cys6 proteins. We show that AD masking and response to the appropriate metabolic signal only occur when a given AD remains attached to its own middle region; middle region swapping results in constitutively active proteins. Finally, we show that the extent to which Leu3p regulates reporter gene expression depends on the intracellular concentration of Leu3p. The possible physiological significance of this observation is discussed in light of the known regulation of Leu3p by Gcn4p.
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Affiliation(s)
- D Wang
- Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907, USA
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Casalone E, Fia G, Barberio C, Cavalieri D, Turbanti L, Polsinelli M. Genetic and biochemical characterization of Saccharomyces cerevisiae mutants resistant to trifluoroleucine. Res Microbiol 1997; 148:613-23. [PMID: 9765846 DOI: 10.1016/s0923-2508(97)88085-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Eighteen mutants resistant to 5',5',5'-trifluoroleucine (TFL), a leucine analog, were isolated in Saccharomyces cerevisiae strains YNN281 and YNN282. The mutants were characterized genetically and clustered in two groups, one comprising all the dominant (TFL1) and the other one all the recessive (tfl2) mutations. Genetic and biochemical data suggested that the dominant mutations are located on the LEU4 gene, coding for alpha-isopropylmalate synthase I. These mutations resulted in accumulation of leucine as a consequence of the synthesis of an enzyme insensitive to the feedback inhibition by leucine. Leucine excretion in the TFL1 mutants appeared to be affected by the genetic background of the strain and was greatly influenced by lysine metabolism. The measurement of intra- and extracellular amino acid concentrations in prototrophic strains carrying TFL1 or tfl2 genes showed that both were leucine overproducers. Some of the TFL-resistant mutants were tested in alcoholic fermentation of grape must: analysis of the fermentation secondary metabolites showed that the major effect of the TFL-resistant strains was an increased production of isoamyl alcohol compared to that of the parental strain.
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Affiliation(s)
- E Casalone
- Department of Animal Biology and Genetics, University of Florence, Italy
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