The coordination of centromere replication, spindle formation, and kinetochore-microtubule interaction in budding yeast.
The kinetochore is a protein complex that assembles on centromeric DNA to mediate chromosome-microtubule interaction. Most eukaryotic cells form the spindle and establish kinetochore-microtubule interaction during mitosis, but budding yeast cells finish these processes in S-phase. It has long been noticed that the S-phase spindle in budding yeast is shorter than that in metaphase, but the biological significance of this short S-phase spindle structure remains unclear. We addressed this issue by using ask1-3, a temperature-sensitive kinetochore mutant that exhibits partially elongated spindles at permissive temperature in the presence of hydroxyurea (HU), a DNA synthesis inhibitor. After exposure to and removal of HU, ask1-3 cells show a delayed anaphase entry. This delay depends on the spindle checkpoint, which monitors kinetochore-microtubule interaction defects. Overproduction of microtubule-associated protein Ase1 or Cin8 also induces spindle elongation in HU-arrested cells. The spindle checkpoint-dependent anaphase entry delay is also observed after ASE1 or CIN8 overexpression in HU-arrested cells. Therefore, the shorter spindle in S-phase cells is likely to facilitate proper chromosome-microtubule interaction.
Liu
Hong
H
Department of Biological Sciences, Florida State University, Tallahassee, Florida, United States of America.
Liang
Fengshan
F
Jin
Fengzhi
F
Wang
Yanchang
Y
D000705:Anaphase; D002478:Cells, Cultured; D002503:Centromere / Q000378:metabolism*; D005800:Genes, Fungal; D006918:Hydroxyurea / Q000494:pharmacology; D018386:Kinetochores / Q000378:metabolism*; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism*; D016196:S Phase; D004718:Saccharomycetales / Q000235:genetics* / Q000378:metabolism; D008941:Spindle Apparatus / Q000378:metabolism*
D008869:Microtubule-Associated Proteins; D006918:Hydroxyurea