Lack of tension at kinetochores activates the spindle checkpoint in budding yeast.
The spindle checkpoint delays the onset of anaphase until all pairs of sister chromatids are attached to the mitotic spindle. The checkpoint could monitor the attachment of microtubules to kinetochores, the tension that results from the two sister chromatids attaching to opposite spindle poles, or both. We tested the role of tension by allowing cells to enter mitosis without a prior round of DNA replication. The unreplicated chromatids are attached to spindle microtubules but are not under tension since they lack a sister chromatid that could attach to the opposite pole. Because the spindle checkpoint is activated in these cells, we conclude that the absence of tension at the yeast kinetochore is sufficient to activate the spindle checkpoint in mitosis.
Stern
B M
BM
Department of Molecular and Cell Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA 02138, USA.
Murray
A W
AW
D002135:Calcium-Binding Proteins / Q000235:genetics / Q000378:metabolism; D002352:Carrier Proteins; D018797:Cell Cycle Proteins / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D018386:Kinetochores / Q000502:physiology*; D064246:Mad2 Proteins; D009687:Nuclear Proteins; D029701:Saccharomyces cerevisiae Proteins; D004718:Saccharomycetales; D015398:Signal Transduction; D008941:Spindle Apparatus / Q000502:physiology*
C066503:CDC6 protein, S cerevisiae; D002135:Calcium-Binding Proteins; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D005656:Fungal Proteins; C577695:MAD2 protein, S cerevisiae; D064246:Mad2 Proteins; D009687:Nuclear Proteins; D029701:Saccharomyces cerevisiae Proteins