title: The repressor Rgt1 and the cAMP-dependent protein kinases control the expression of the SUC2 gene in Saccharomyces cerevisiae.
abstract: BACKGROUND
  A low level of glucose is required for maximal transcription of the SUC2 gene in Saccharomyces cerevisiae. Although the repressor Rgt1 binds the SUC2 promoter in gel-shift assays, it has been reported that Rgt1 has only minimal effects on SUC2 expression. Rgt1 acts together with Mth1 to repress the HXT genes encoding glucose transporters, and the release of Rgt1 from some HXT promoters requires cAMP-dependent protein kinase (PKA) activity.
  
  
  METHODS
  The genes RGT1 and MTH1 have been disrupted and the SUC2 promoter modified in several S. cerevisiae backgrounds. Yeast cells were grown in different carbon sources in the presence or absence of 0.1 or 2% glucose, and invertase was assayed in whole cells.
  
  
  RESULTS
  Galactose, glycerol or ethanol hindered invertase induction by low glucose, but lactate did not. During growth in lactate, deletion of RGT1 or MTH1 caused a marked increase in invertase levels, and elimination of the Rgt1-binding site in the SUC2 promoter caused also invertase induction. PKA activity decreased invertase levels in cells growing in lactate, and increased them during growth in lactate+0.1% glucose.
  
  
  CONCLUSIONS
  The low level of expression of SUC2 in the absence of glucose is mainly due to repression by the Rgt1-Mth1 complex. Repression is dependent on PKA activity, but not on any specific Tpk isoenzyme.
  
  
  CONCLUSIONS
  The results show that previously overlooked regulatory elements, such as Rgt1 and Tpks, participate in the control of SUC2 expression in S.cerevisiae.
authors: Department of Metabolism and Cell Signalling, Instituto de Investigaciones Biomédicas "Alberto Sols" CSIC-UAM Arturo Duperier 4, E-28029 Madrid, Spain. Electronic address: jmgancedo@iib.uam.es.
authors: Juana M
authors: JM
authors: Gancedo
authors: Department of Metabolism and Cell Signalling, Instituto de Investigaciones Biomédicas "Alberto Sols" CSIC-UAM Arturo Duperier 4, E-28029 Madrid, Spain. Electronic address: clflores@iib.uam.es.
authors: Carmen-Lisset
authors: CL
authors: Flores
authors: Department of Metabolism and Cell Signalling, Instituto de Investigaciones Biomédicas "Alberto Sols" CSIC-UAM Arturo Duperier 4, E-28029 Madrid, Spain. Electronic address: cgancedo@iib.uam.es.
authors: Carlos
authors: C
authors: Gancedo
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites / Q000235:genetics; D054751:Cyclic AMP-Dependent Protein Kinase Catalytic Subunits / Q000235:genetics / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D000431:Ethanol / Q000494:pharmacology; D005690:Galactose / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects; D005947:Glucose / Q000494:pharmacology; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D011401:Promoter Regions, Genetic / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D043324:beta-Fructofuranosidase / Q000235:genetics / Q000378:metabolism*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D004268:DNA-Binding Proteins; D007527:Isoenzymes; C118806:MTH1 protein, S cerevisiae; C102114:RGT1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D000431:Ethanol; D054751:Cyclic AMP-Dependent Protein Kinase Catalytic Subunits; D017868:Cyclic AMP-Dependent Protein Kinases; C457179:TPK2 protein, S cerevisiae; C579078:Tpk1 protein, S cerevisiae; C509333:Tpk3 protein, S cerevisiae; C468437:SUC2 protein, S cerevisiae; D043324:beta-Fructofuranosidase; D005947:Glucose; D005690:Galactose
keywords: Glucose; Invertase; PKA; Rgt1; SUC2; Yeast