The kinesin Eg5 drives poleward microtubule flux in Xenopus laevis egg extract spindles.
Although mitotic and meiotic spindles maintain a steady-state length during metaphase, their antiparallel microtubules slide toward spindle poles at a constant rate. This "poleward flux" of microtubules occurs in many organisms and may provide part of the force for chromosome segregation. We use quantitative image analysis to examine the role of the kinesin Eg5 in poleward flux in metaphase Xenopus laevis egg extract spindles. Pharmacological inhibition of Eg5 results in a dose-responsive slowing of flux, and biochemical depletion of Eg5 significantly decreases the flux rate. Our results suggest that ensembles of nonprocessive Eg5 motors drive flux in metaphase Xenopus extract spindles.
Miyamoto
David T
DT
Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA. miyamoto@post.harvard.edu
Perlman
Zachary E
ZE
Burbank
Kendra S
KS
Groen
Aaron C
AC
Mitchison
Timothy J
TJ
D000818:Animals; D002455:Cell Division / Q000502:physiology*; D002457:Cell Extracts / Q000737:chemistry; D016764:Cell Polarity / Q000502:physiology*; D020090:Chromosome Segregation / Q000187:drug effects / Q000502:physiology; D048749:Cytokinesis / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D019044:Image Cytometry; D016547:Kinesins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008677:Metaphase / Q000187:drug effects / Q000502:physiology; D008856:Microscopy, Fluorescence; D008870:Microtubules / Q000378:metabolism*; D020409:Molecular Motor Proteins; D009865:Oocytes / Q000737:chemistry; D011743:Pyrimidines / Q000494:pharmacology; D008941:Spindle Apparatus / Q000502:physiology*; D013347:Subcellular Fractions / Q000737:chemistry / Q000378:metabolism; D013871:Thiones / Q000494:pharmacology; D029867:Xenopus Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D014982:Xenopus laevis
D002457:Cell Extracts; D004791:Enzyme Inhibitors; C088335:KIF11 protein, Xenopus; D020409:Molecular Motor Proteins; D011743:Pyrimidines; D013871:Thiones; D029867:Xenopus Proteins; C400223:monastrol; D016547:Kinesins