A role of Sep1 (= Kem1, Xrn1) as a microtubule-associated protein in Saccharomyces cerevisiae

H. Interthal, C. Bellocq, J. Bahler, V. I. Bashkirov, S. Edelstein, W. D. Heyer

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Abstract

Saccharomyces cerevisiae cells lacking the SEP1 (also known as XRN1, KEM1, DST2, RAR5) gene function exhibit a number of phenotypes in cellular processes related to microtubule function. Mutant cells show increased sensitivity to the microtubule-destabilizing drug benomyl, increased chromosome loss, a karyogamy defect, impaired spindle pole body separation, and defective nuclear migration towards the bud neck. Analysis of the arrest morphology and of the survival during arrest strongly suggests a structural defect accounting for the benomyl hypersensitivity, rather than a regulatory defect in a checkpoint. Biochemical analysis of the purified Sep1 protein demonstrates its ability to promote the polymerization of porcine brain and authentic S. cerevisiae tubulin into flexible microtubules in vitro. Furthermore, Sep1 co-sediments with these microtubules in sucrose cushion centrifugation. Genetic analysis of double mutant strains containing a mutation in SEP1 and in one of the genes coding for α- or β-tubulin further suggests interaction between Sep1 and microtubules. Taken together these three lines of evidence constitute compelling evidence for a role of Sep1 as an accessory protein in microtubule function in the yeast S. cerevisiae.

Original languageEnglish (US)
Pages (from-to)1057-1066
Number of pages10
JournalEMBO Journal
Volume14
Issue number6
StatePublished - 1995
Externally publishedYes

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Keywords

  • Benomyl
  • MAP
  • Spindle pole body
  • Tubulin
  • Yeast

ASJC Scopus subject areas

  • Cell Biology
  • Genetics

Cite this

Interthal, H., Bellocq, C., Bahler, J., Bashkirov, V. I., Edelstein, S., & Heyer, W. D. (1995). A role of Sep1 (= Kem1, Xrn1) as a microtubule-associated protein in Saccharomyces cerevisiae. EMBO Journal, 14(6), 1057-1066.