Grr1p is required for transcriptional induction of amino acid permease genes and proper transcriptional regulation of genes in carbon metabolism of Saccharomyces cerevisiae.
The F-box protein Grr1p is involved in cell cycle regulation, glucose repression and transcriptional induction of the amino acid permease (AAP) gene AGP1. We investigated the role of Grr1p in amino acid-mediated induction of AAP genes by performing batch cultivations with a wild-type strain and a grr1Delta strain and adding citrulline in the exponential phase. Whole-genome transcription analyses were performed on samples from each cultivation, both immediately before and 30 min after citrulline addition. Transcriptional induction of the AAP genes AGP1, BAP2, BAP3, DIP5, GNP1 and TAT1 is fully dependent on Grr1p. Comparison of the grr1Delta strain with the reference strain in the absence of citrulline revealed that GRR1 disruption leads to increased transcription of numerous genes. These encode enzymes in the tricarboxylic acid cycle, the pentose-phosphate pathway and both glucose and starch metabolism. Promoter analysis showed that many of the genes with increased transcription display Mig1p- and/or Msn2p/Msn4p-binding sites. Increased expression of glucose-repressed genes in the grr1Delta strain may be explained by the reduced expression of the hexose transporter genes HXT1, HXT2, HXT3 and HXT4 and a subsequent lowering of the glucose uptake; and the effect of GRR1 deletion on general carbon metabolism may therefore be indirect. Finally, none of the genes known to be primarily involved in cell cycle regulation displayed different expression levels in the grr1Delta cells as compared with the reference strain, suggesting that the role of Grr1p in cell cycle regulation does not include any transcriptional component.
Eckert-Boulet
Nadine
N
Center for Microbial Biotechnology, BioCentrum-DTU, Technical University of Denmark, Building 223, BioCentrum-DTU, 2800 Lyngby, Denmark.
Regenberg
Birgitte
B
Nielsen
Jens
J
D026905:Amino Acid Transport Systems / Q000235:genetics*; D001692:Biological Transport / Q000235:genetics; D002952:Citric Acid Cycle / Q000235:genetics; D044783:F-Box Proteins; D015966:Gene Expression Regulation, Fungal; D005947:Glucose / Q000235:genetics / Q000378:metabolism; D010427:Pentose Phosphate Pathway / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics*; D013213:Starch / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic; D044767:Ubiquitin-Protein Ligases / Q000235:genetics*
D026905:Amino Acid Transport Systems; D044783:F-Box Proteins; D029701:Saccharomyces cerevisiae Proteins; C071032:GRR1 protein, S cerevisiae; D013213:Starch; D044767:Ubiquitin-Protein Ligases; D005947:Glucose