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Length-dependent anisotropic scaling of spindle shape.

Young S, Besson S, Welburn JP - Biol Open (2014)

Bottom Line: We demonstrate that spindle shape scaling is independent of the nature of the molecules that regulate dynamic microtubule properties, but is dependent on the steady-state metaphase spindle length.The shape of the spindle scales anisotropically with increasing length.Our results suggest that intrinsic mechanisms control the shape of the spindle to ensure the efficient capture and alignment of chromosomes independently of spindle length.

View Article: PubMed Central - PubMed

Affiliation: Wellcome Trust Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, Scotland, UK.

No MeSH data available.


Related in: MedlinePlus

Clasp1 and Clasp2 act on kinetochore-fibers to stabilize the steady-state metaphase spindle.(A) Time-lapse imaging of U2OS cells expressing mCherry-tubulin after a STLC washout, treated with indicated siRNA. (B–E) Graphs representing the average spindle length, width and aspect ratio and the corresponding SD during elongation for each condition described in panel A. Scale bar: 10 µm.
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f03: Clasp1 and Clasp2 act on kinetochore-fibers to stabilize the steady-state metaphase spindle.(A) Time-lapse imaging of U2OS cells expressing mCherry-tubulin after a STLC washout, treated with indicated siRNA. (B–E) Graphs representing the average spindle length, width and aspect ratio and the corresponding SD during elongation for each condition described in panel A. Scale bar: 10 µm.

Mentions: Clasp1, Clasp2 and Kid may act antagonistically on the microtubule dynamics of kinetochore-fibers. To test whether the spindle contraction and changes in spindle geometry was due to the absence of Clasps at kinetochore-fiber ends, we examined spindle elongation in absence of kinetochore-fibers by depleting the kinetochore protein Nuf2. We first depleted Nuf2 alone, which results in abnormally long spindles (Fig. 3A,B; supplementary material Fig. S2G,H) consistent with prior work (DeLuca et al., 2006). Upon Clasp2/Nuf2 co-depletion, the biphasic spindle assembly behavior was suppressed (Fig. 3A,B; supplementary material Fig. S2I,J). The spindle reached a steady-state spindle length of 12.8 ± 2.3 µm, similar to control spindles (supplementary material Fig. S1C). We propose that upon end-on attachment of kinetochore-fibers to kinetochores, kinetochore-fibers generate an inward pulling force to stabilize the metaphase spindle. In the absence of Clasps, the shorter centrosome and spindle-generated interpolar microtubules determine the steady-state spindle length. Taken together, our data suggest that Clasp1 and Clasp2 act both on kinetochore-fibers, to enable a monophasic spindle elongation, and on spindle microtubules to set the steady-state spindle length.


Length-dependent anisotropic scaling of spindle shape.

Young S, Besson S, Welburn JP - Biol Open (2014)

Clasp1 and Clasp2 act on kinetochore-fibers to stabilize the steady-state metaphase spindle.(A) Time-lapse imaging of U2OS cells expressing mCherry-tubulin after a STLC washout, treated with indicated siRNA. (B–E) Graphs representing the average spindle length, width and aspect ratio and the corresponding SD during elongation for each condition described in panel A. Scale bar: 10 µm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4265759&req=5

f03: Clasp1 and Clasp2 act on kinetochore-fibers to stabilize the steady-state metaphase spindle.(A) Time-lapse imaging of U2OS cells expressing mCherry-tubulin after a STLC washout, treated with indicated siRNA. (B–E) Graphs representing the average spindle length, width and aspect ratio and the corresponding SD during elongation for each condition described in panel A. Scale bar: 10 µm.
Mentions: Clasp1, Clasp2 and Kid may act antagonistically on the microtubule dynamics of kinetochore-fibers. To test whether the spindle contraction and changes in spindle geometry was due to the absence of Clasps at kinetochore-fiber ends, we examined spindle elongation in absence of kinetochore-fibers by depleting the kinetochore protein Nuf2. We first depleted Nuf2 alone, which results in abnormally long spindles (Fig. 3A,B; supplementary material Fig. S2G,H) consistent with prior work (DeLuca et al., 2006). Upon Clasp2/Nuf2 co-depletion, the biphasic spindle assembly behavior was suppressed (Fig. 3A,B; supplementary material Fig. S2I,J). The spindle reached a steady-state spindle length of 12.8 ± 2.3 µm, similar to control spindles (supplementary material Fig. S1C). We propose that upon end-on attachment of kinetochore-fibers to kinetochores, kinetochore-fibers generate an inward pulling force to stabilize the metaphase spindle. In the absence of Clasps, the shorter centrosome and spindle-generated interpolar microtubules determine the steady-state spindle length. Taken together, our data suggest that Clasp1 and Clasp2 act both on kinetochore-fibers, to enable a monophasic spindle elongation, and on spindle microtubules to set the steady-state spindle length.

Bottom Line: We demonstrate that spindle shape scaling is independent of the nature of the molecules that regulate dynamic microtubule properties, but is dependent on the steady-state metaphase spindle length.The shape of the spindle scales anisotropically with increasing length.Our results suggest that intrinsic mechanisms control the shape of the spindle to ensure the efficient capture and alignment of chromosomes independently of spindle length.

View Article: PubMed Central - PubMed

Affiliation: Wellcome Trust Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, Scotland, UK.

No MeSH data available.


Related in: MedlinePlus