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Actin checkpoint

Jonathan B Weitzman

Author Affiliations

Genome Biology 2001, 2:spotlight-20010719-01  doi:10.1186/gb-spotlight-20010719-01


The electronic version of this article is the complete one and can be found online at:


Published:19 July 2001

© 2001 BioMed Central Ltd

Research news

Mitotic segregation of chromosomes depends on correct assembly of the bipolar spindle and mitosis is delayed by the spindle assembly checkpoint (SAC). In the July 19 Nature, Gachet et al., at the National Institute for Medical Research and University College London, describe a different mitotic checkpoint in yeast (Nature 2001, 412:352-355). They investigated the link between organization of the actin cytoskeleton and the cell cycle in the fission yeast Schizosaccharomyces pombe. They synchronized cells in early G2 and then grew them in the presence of latrunculin B (Lat B), an inhibitor of actin polymerization. Lat B-treated cells arrested in mitosis with short and misoriented spindles. Actin depolymerization affected Cut1-mediated cohesin cleavage and sister chromatid separation. The effect of Lat B was independent of SAC activation. Gachet et al. screened yeast mutants to identify checkpoint components and found that cells lacking the Atf1 factor were hypersensitive to Lat B, as were mutants lacking the upstream Sty1 MAP kinase. Thus the integrity of the actin cytoskeleton, spindle orientation and stress-activated kinase signaling determine the nature of this new mitotic checkpoint.

References

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