Yeast BUD5, encoding a putative GDP-GTP exchange factor, is necessary for bud site selection and interacts with bud formation gene BEM1

Cell. 1991 Jun 28;65(7):1213-24. doi: 10.1016/0092-8674(91)90016-r.


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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Cell Compartmentation
  • Cell Cycle
  • Cloning, Molecular
  • DNA, Fungal / genetics
  • GTP-Binding Proteins / genetics*
  • Genes, Fungal*
  • Genetic Complementation Test
  • Molecular Sequence Data
  • Morphogenesis
  • Phenotype
  • Restriction Mapping
  • Saccharomyces cerevisiae / cytology*
  • Saccharomyces cerevisiae / genetics


  • DNA, Fungal
  • GTP-Binding Proteins

Associated data

  • GENBANK/M59201
  • GENBANK/M63552
  • GENBANK/M63700
  • GENBANK/M63702
  • GENBANK/M63718
  • GENBANK/S40357
  • GENBANK/S40365
  • GENBANK/S63145
  • GENBANK/S63146
  • GENBANK/S63147
  • GENBANK/S63148