TY - JOUR
T1 - Evidence for an Upper Limit to Mitotic Spindle Length
AU - Wühr, Martin
AU - Chen, Yao
AU - Dumont, Sophie
AU - Groen, Aaron C.
AU - Needleman, Daniel J.
AU - Salic, Adrian
AU - Mitchison, Timothy J.
N1 - Funding Information:
We would like to thank Jagesh Shah, Andrew Murray, Marc Kirschner, Rebecca Ward, Yifat Merbl, Tom Maresca, Jay Gatlin, Cell division group Woods Hole, Eva Kiermaier, and people in the Mitchison lab for helpful suggestions and discussion; Olaf Stemmann for training; Michael Rape for plasmid of EmiI; Jim Horn for technical assistance; and Nikon Imaging Center (HMS) and Zeiss Woods Hole for imaging assistance. D.J.N. was supported by the Life Sciences Research Foundation, sponsored by Novartis. This work was supported by the National Institutes of Health (NIH) grants GM39565 and P50 GM068763-1.
PY - 2008/8/26
Y1 - 2008/8/26
N2 - Size specification of macromolecular assemblies in the cytoplasm is poorly understood [1]. In principle, assemblies could scale with cell size or use intrinsic mechanisms. For the mitotic spindle, scaling with cell size is expected, because the function of this assembly is to physically move sister chromatids into the center of nascent daughter cells. Eggs of Xenopus laevis are among the largest cells known that cleave completely during cell division. Cell length in this organism changes by two orders of magnitude (∼1200 μm to ∼12 μm) while it develops from a fertilized egg into a tadpole [2]. We wondered whether, and how, mitotic spindle length and morphology adapt to function at these different length scales. Here, we show that spindle length increases with cell length in small cells, but in very large cells spindle length approaches an upper limit of ∼60 μm. Further evidence for an upper limit to spindle length comes from an embryonic extract system that recapitulates mitotic spindle assembly in a test tube. We conclude that early mitotic spindle length in Xenopus laevis is uncoupled from cell length, reaching an upper bound determined by mechanisms that are intrinsic to the spindle.
AB - Size specification of macromolecular assemblies in the cytoplasm is poorly understood [1]. In principle, assemblies could scale with cell size or use intrinsic mechanisms. For the mitotic spindle, scaling with cell size is expected, because the function of this assembly is to physically move sister chromatids into the center of nascent daughter cells. Eggs of Xenopus laevis are among the largest cells known that cleave completely during cell division. Cell length in this organism changes by two orders of magnitude (∼1200 μm to ∼12 μm) while it develops from a fertilized egg into a tadpole [2]. We wondered whether, and how, mitotic spindle length and morphology adapt to function at these different length scales. Here, we show that spindle length increases with cell length in small cells, but in very large cells spindle length approaches an upper limit of ∼60 μm. Further evidence for an upper limit to spindle length comes from an embryonic extract system that recapitulates mitotic spindle assembly in a test tube. We conclude that early mitotic spindle length in Xenopus laevis is uncoupled from cell length, reaching an upper bound determined by mechanisms that are intrinsic to the spindle.
KW - CELLBIO
UR - http://www.scopus.com/inward/record.url?scp=49649119879&partnerID=8YFLogxK
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U2 - 10.1016/j.cub.2008.07.092
DO - 10.1016/j.cub.2008.07.092
M3 - Article
C2 - 18718761
AN - SCOPUS:49649119879
SN - 0960-9822
VL - 18
SP - 1256
EP - 1261
JO - Current Biology
JF - Current Biology
IS - 16
ER -