title: Functional analysis of the Zygosaccharomyces rouxii Fps1p homologue.
abstract: The osmotolerant yeast Zygosaccharomyces rouxii accumulates the polyols glycerol and D-arabitol intracellularly in response to hyperosmotic stress, but the membrane transport proteins regulating polyol accumulation have not been studied. We have cloned and characterized a FPS1 homologue in Z. rouxii NRRL Y2547, and its sequence revealed a 2709 bp open reading frame encoding a peptide of 692 deduced amino acids with 56.9% identity to the Saccharomyces cerevisiae Fps1p. The role of this putative membrane channel protein in polyol accumulation and release during osmoregulation was investigated. The Z. rouxii FPS1 (ZrFPS1) complemented the S. cerevisiae fps1Delta growth defect and glycerol release upon hypo-osmotic shock. Deletion of ZrFPS1 did not affect growth on glycerol as sole carbon source, suggesting that other transport proteins are involved in the uptake of glycerol. However, mutants lacking ZrFPS1 exhibited a significant decrease in glycerol and D-arabitol efflux and poor growth during hypo-osmotic conditions, suggesting that ZrFPS1 might be involved in D-arabitol transport in addition to glycerol. This is the first demonstration of a yeast gene that affects D-arabitol transport. The full-length ZrFPS1 gene sequence including upstream promoter has been deposited in the public database under Accession No. AY488133.
authors.affiliation: Department of Microbiology, University of Stellenbosch, Private Bag X1, Matieland, 7602, South Africa.
authors.forename: Xue-Ming
authors.initials: XM
authors.lastname: Tang
authors.forename: Gerald
authors.initials: G
authors.lastname: Kayingo
authors.forename: Bernard A
authors.initials: BA
authors.lastname: Prior
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D005990:Glycerol / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013402:Sugar Alcohols / Q000378:metabolism; D014882:Water-Electrolyte Balance; D020068:Zygosaccharomyces / Q000235:genetics / Q000378:metabolism* / Q000502:physiology
chemical_list: C093263:FPS1 protein, S cerevisiae; D005656:Fungal Proteins; D008565:Membrane Proteins; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; D013402:Sugar Alcohols; D005990:Glycerol; C014999:arabitol