title: The yeast gene MSC2, a member of the cation diffusion facilitator family, affects the cellular distribution of zinc.
abstract: The sequence of the yeast gene YDR205W places it within the family of cation diffusion facilitators: membrane proteins that transport transition metals. Deletion of YDR205W was reported to result in an increase in unequal sister chromatid recombination and was named meiotic sister chromatid recombination 2 (MSC2; Thompson, D. A., and Stahl, F. W. (1999) Genetics 153, 621-641). We report here that a msc2 strain shows a phenotype of decreased viability in glycerol-ethanol media at 37 degrees C. Associated with decreased growth is an abnormal morphology typified by an increase in size of both cells and vacuoles. Addition of extracellular Zn2+ completely suppresses the morphological changes and partially suppresses the growth defect. Regardless of the concentration of Zn2+ in the media, the msc2 strain had a higher Zn2+ content than wild type cells. Zinquin staining also revealed that msc2 had a marked increase in fluorescence compared with the wild type, again reflecting an increase in intracellular Zn2+. The deletion strain accumulated excess Zn2+ in nuclei-enriched membrane fractions, and when grown at 37 degrees C in glycerol-ethanol media, it showed a decreased expression of Zn2+-regulated genes. The expression of genes regulated by either Fe2+ or Cu2+ was not affected. An epitope-tagged Msc2p was localized to the endoplasmic reticulum/nucleus. These results suggest that Msc2p affects the cellular distribution of zinc and, in particular, the zinc content of nuclei.
authors.affiliation: Division of Immunology and Cell Biology, Department of Pathology, School of Medicine, University of Utah, Salt Lake City, UT 84132, USA.
authors.forename: L
authors.initials: L
authors.lastname: Li
authors.forename: J
authors.initials: J
authors.lastname: Kaplan
mesh_terms: D002352:Carrier Proteins / Q000235:genetics / Q000502:physiology*; D027682:Cation Transport Proteins; D002467:Cell Nucleus / Q000378:metabolism; D003470:Culture Media; D005656:Fungal Proteins / Q000502:physiology; D015966:Gene Expression Regulation, Fungal; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology*; D010641:Phenotype; D012331:RNA, Fungal / Q000096:biosynthesis; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000254:growth & development / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D017384:Sequence Deletion; D015032:Zinc / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D027682:Cation Transport Proteins; D003470:Culture Media; D005656:Fungal Proteins; C429021:MSC2 protein, S cerevisiae; D008565:Membrane Proteins; D012331:RNA, Fungal; D029701:Saccharomyces cerevisiae Proteins; D006861:Hydrogen Peroxide; D015032:Zinc