title: Gene regulatory changes in yeast during life extension by nutrient limitation.
abstract: Genetic analyses aimed at identification of the pathways and downstream effectors of calorie restriction (CR) in the yeast Saccharomyces cerevisiae suggest the importance of central metabolism for the extension of replicative life span by CR. However, the limited gene expression studies to date are not informative, because they have been conducted using cells grown in batch culture which markedly departs from the conditions under which yeasts are grown during life span determinations. In this study, we have examined the gene expression changes that occur during either glucose limitation or elimination of nonessential-amino acids, both of which enhance yeast longevity, culturing cells in a chemostat at equilibrium, which closely mimics conditions they encounter during life span determinations. Expression of 59 genes was examined quantitatively by real-time, reverse transcriptase polymerase chain reaction (qRT-PCR), and the physiological state of the cultures was monitored. Extensive gene expression changes were detected, some of which were common to both CR regimes. The most striking of these was the induction of tricarboxylic acid (TCA) cycle and retrograde response target genes, which appears to be at least partially due to the up-regulation of the HAP4 gene. These gene regulatory events portend an increase in the generation of biosynthetic intermediates necessary for the production of daughter cells, which is the measure of yeast replicative life span.
authors.affiliation: Department of Medicine and the Tulane Center for Aging, Tulane University Health Sciences Center, 1430 Tulane Avenue, New Orleans, LA 70112, USA.
authors.forename: Jinqing
authors.initials: J
authors.lastname: Wang
authors.forename: James C
authors.initials: JC
authors.lastname: Jiang
authors.forename: S Michal
authors.initials: SM
authors.lastname: Jazwinski
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D023081:CCAAT-Binding Factor / Q000235:genetics / Q000378:metabolism; D002952:Citric Acid Cycle / Q000235:genetics; D003470:Culture Media; D018507:Gene Expression Regulation, Developmental; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D005943:Gluconeogenesis / Q000235:genetics; D005947:Glucose / Q000378:metabolism; D006003:Glycogen / Q000096:biosynthesis; D006019:Glycolysis / Q000235:genetics; D006038:Glyoxylates / Q000378:metabolism; D008954:Models, Biological; D009004:Monosaccharide Transport Proteins / Q000235:genetics / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism; D010427:Pentose Phosphate Pathway / Q000235:genetics; D019289:Pyruvic Acid / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D014199:Trehalose / Q000096:biosynthesis
chemical_list: D000596:Amino Acids; D023081:CCAAT-Binding Factor; D003470:Culture Media; D006038:Glyoxylates; C061437:HAP4 protein, S cerevisiae; D009004:Monosaccharide Transport Proteins; D029701:Saccharomyces cerevisiae Proteins; D019289:Pyruvic Acid; D006003:Glycogen; D014199:Trehalose; D005947:Glucose; C031150:glyoxylic acid; D009584:Nitrogen