title: Repression of nitrogen catabolic genes by ammonia and glutamine in nitrogen-limited continuous cultures of Saccharomyces cerevisiae.
abstract: Growth of Saccharomyces cerevisiae on ammonia and glutamine decreases the expression of many nitrogen catabolic genes to low levels. To discriminate between ammonia- and glutamine-driven repression of GAP1, PUT4, GDH1 and GLN1, a gln1-37 mutant was used. This mutant is not able to convert ammonia into glutamine. Glutamine-limited continuous cultures were used to completely derepress the expression of GAP1, PUT4, GDH1 and GLN1. Following an ammonia pulse, the expression of GAP1, PUT4 and GDH1 decreased while the intracellular glutamine concentration remained constant, both in the cytoplasm and in the vacuole. Therefore, it was concluded that ammonia causes gene repression independent of the intracellular glutamine concentration. The expression of GLN1 was not decreased by an ammonia pulse but solely by a glutamine pulse. Analysis of the mRNA levels of ILV5 and HIS4 showed that the response of the two biosynthetic genes, GDH1 and GLN1, to ammonia and glutamine in the wild-type and gln1-37 was not due to changes in general transcription of biosynthetic genes. Ure2p has been shown to be an essential element for nitrogen-regulated gene expression. Deletion of URE2 in the gln1-37 background prevented repression of gene expression by ammonia, showing that the ammonia-induced repression is not caused by a general stress response but represents a specific signal for nitrogen catabolite regulation.
authors.affiliation: Unilever Research Laboratorium Vlaardingen, Olivier van Noortlaan120, 3133 AT Viaardingen, The Netherlands.
authors.forename: Eelko G
authors.initials: EG
authors.lastname: Ter Schure
authors.affiliation: Department of Molecular Cell Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
authors.forename: Herman H W
authors.initials: HHW
authors.lastname: Silljé
authors.affiliation: Department of Molecular Cell Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
authors.forename: Edgar E
authors.initials: EE
authors.lastname: Vermeulen
authors.affiliation: Department of Molecular Cell Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
authors.forename: Jan-Willem
authors.initials: JW
authors.lastname: Kalhorn
authors.affiliation: Department of Molecular Cell Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
authors.forename: Arie J
authors.initials: AJ
authors.lastname: Verkleij
authors.affiliation: Department of Molecular Cell Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
authors.forename: Johannes
authors.initials: J
authors.lastname: Boonstra
authors.affiliation: Unilever Research Laboratorium Vlaardingen, Olivier van Noortlaan120, 3133 AT Viaardingen, The Netherlands.|Department of Molecular Cell Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
authors.forename: C Theo
authors.initials: CT
authors.lastname: Verrips
mesh_terms: D026905:Amino Acid Transport Systems; D026921:Amino Acid Transport Systems, Neutral; D000641:Ammonia / Q000378:metabolism / Q000494:pharmacology*; D015152:Blotting, Northern; D005656:Fungal Proteins / Q000235:genetics* / Q000502:physiology; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D018086:Glutamate Dehydrogenase (NADP+) / Q000235:genetics / Q000378:metabolism; D005974:Glutamate-Ammonia Ligase / Q000235:genetics / Q000378:metabolism; D005973:Glutamine / Q000378:metabolism / Q000494:pharmacology*; D005979:Glutathione Peroxidase; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism*; D011328:Prions; D012333:RNA, Messenger / Q000032:analysis; D012097:Repressor Proteins / Q000235:genetics / Q000502:physiology; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D014158:Transcription, Genetic
chemical_list: D026905:Amino Acid Transport Systems; D026921:Amino Acid Transport Systems, Neutral; D005656:Fungal Proteins; D026901:Membrane Transport Proteins; D011328:Prions; D012333:RNA, Messenger; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D005973:Glutamine; D000641:Ammonia; C033082:proline transporter; D005979:Glutathione Peroxidase; C067020:URE2 protein, S cerevisiae; D018086:Glutamate Dehydrogenase (NADP+); D005974:Glutamate-Ammonia Ligase; D009584:Nitrogen