title: Characterization of the yeast ionome: a genome-wide analysis of nutrient mineral and trace element homeostasis in Saccharomyces cerevisiae.
abstract: BACKGROUND
  Nutrient minerals are essential yet potentially toxic, and homeostatic mechanisms are required to regulate their intracellular levels. We describe here a genome-wide screen for genes involved in the homeostasis of minerals in Saccharomyces cerevisiae. Using inductively coupled plasma-atomic emission spectroscopy (ICP-AES), we assayed 4,385 mutant strains for the accumulation of 13 elements (calcium, cobalt, copper, iron, potassium, magnesium, manganese, nickel, phosphorus, selenium, sodium, sulfur, and zinc). We refer to the resulting accumulation profile as the yeast 'ionome'.
  
  
  RESULTS
  We identified 212 strains that showed altered ionome profiles when grown on a rich growth medium. Surprisingly few of these mutants (four strains) were affected for only one element. Rather, levels of multiple elements were altered in most mutants. It was also remarkable that only six genes previously shown to be involved in the uptake and utilization of minerals were identified here, indicating that homeostasis is robust under these replete conditions. Many mutants identified affected either mitochondrial or vacuolar function and these groups showed similar effects on the accumulation of many different elements. In addition, intriguing positive and negative correlations among different elements were observed. Finally, ionome profile data allowed us to correctly predict a function for a previously uncharacterized gene, YDR065W. We show that this gene is required for vacuolar acidification.
  
  
  CONCLUSIONS
  Our results indicate the power of ionomics to identify new aspects of mineral homeostasis and how these data can be used to develop hypotheses regarding the functions of previously uncharacterized genes.
authors.affiliation: Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA. eide@nutrisci.wisc.edu
authors.forename: David J
authors.initials: DJ
authors.lastname: Eide
authors.forename: Suzanne
authors.initials: S
authors.lastname: Clark
authors.forename: T Murlidharan
authors.initials: TM
authors.lastname: Nair
authors.forename: Mathias
authors.initials: M
authors.lastname: Gehl
authors.forename: Michael
authors.initials: M
authors.lastname: Gribskov
authors.forename: Mary Lou
authors.initials: ML
authors.lastname: Guerinot
authors.forename: Jeffrey F
authors.initials: JF
authors.lastname: Harper
mesh_terms: D004602:Elements; D017353:Gene Deletion; D020869:Gene Expression Profiling; D005800:Genes, Fungal / Q000235:genetics; D016681:Genome, Fungal / Q000235:genetics*; D006706:Homeostasis / Q000502:physiology*; D008903:Minerals / Q000378:metabolism*; D008928:Mitochondria / Q000378:metabolism; D015388:Organelles / Q000378:metabolism; D010641:Phenotype; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000235:genetics* / Q000378:metabolism*; D013054:Spectrophotometry, Atomic; D014131:Trace Elements / Q000378:metabolism*; D014617:Vacuoles / Q000378:metabolism
chemical_list: D004602:Elements; D008903:Minerals; D014131:Trace Elements