Aquaporins in Saccharomyces: Genetic and functional distinctions between laboratory and wild-type strains
Embargo until
Date
1998-10-16
Journal Title
Journal ISSN
Volume Title
Publisher
American Society for Biochemistry and Molecular Biology
Abstract
Aquaporin water channel proteins mediate the transport of water across cell membranes in numerous species. The Saccharomyces genome data base contains an open reading frame (here designated AQY1) that encodes a protein with strong homology to aquaporins. AQY1 from laboratory and wild-type strains of Saccharomyces were expressed in Xenopus oocytes to determine the coefficients of osmotic water permeability (Pf). Oocytes injected with wild-type AQY1 cRNAs exhibit high Pf values, whereas oocytes injected with AQY1 cRNAs from laboratory strains exhibit low Pf values and have reduced levels of Aqy1p due to two amino acid substitutions. When the AQY1 gene was deleted from a wild-type yeast and cells were cultured in vitro with cycled hypo-osmolar or hyper-osmolar stresses, the AQY1 null yeast showed significantly improved viability when compared with the parental wild-type strain. We conclude that Saccharomyces cerevisiae contains at least one aquaporin gene, but it is not functional in laboratory strains due to apparent negative selection pressures resulting from in vitro methods.
Description
Keywords
Aquaporins/genetics, Water/metabolism, Saccharomyces cerevisiae/genetics, Saccharomyces cerevisiae Proteins
Citation
J Biol Chem. 1998 Oct 16;273(42):27565-72. doi: 10.1074/jbc.273.42.27565