title: Yeast BUD5, encoding a putative GDP-GTP exchange factor, is necessary for bud site selection and interacts with bud formation gene BEM1.
abstract: Cells of the yeast S. cerevisiae choose bud sites in an axial or bipolar spatial pattern depending on their cell type. We have identified a gene, BUD5, that resembles BUD1 and BUD2 in being required for both patterns; bud5- mutants also exhibit random budding in all cell types. The BUD5 nucleotide sequence predicts a protein of 538 amino acids that has similarity to the S. cerevisiae CDC25 product, an activator of RAS proteins that catalyzes GDP-GTP exchange. Two potential targets of BUD5 are known: BUD1 (RSR1) and CDC42, proteins involved in bud site selection and bud formation, respectively, that have extensive similarity to RAS. We also show that BUD5 interacts functionally with a gene, BEM1, that is required for bud formation. This interaction provides further support for the view that products involved in bud site selection guide the positioning of a complex necessary for bud formation.
authors.affiliation: Department of Biochemistry and Biophysics, University of California, San Francisco 94143.
authors.forename: J
authors.initials: J
authors.lastname: Chant
authors.forename: K
authors.initials: K
authors.lastname: Corrado
authors.forename: J R
authors.initials: JR
authors.lastname: Pringle
authors.forename: I
authors.initials: I
authors.lastname: Herskowitz
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002451:Cell Compartmentation; D002453:Cell Cycle; D003001:Cloning, Molecular; D004271:DNA, Fungal / Q000235:genetics; D019204:GTP-Binding Proteins / Q000235:genetics*; D005800:Genes, Fungal; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D009024:Morphogenesis; D010641:Phenotype; D015183:Restriction Mapping; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000235:genetics
chemical_list: D004271:DNA, Fungal; D019204:GTP-Binding Proteins