Abstract
In Xenopus laevis egg extracts, TPX2 is required for the Ran-GTP-dependent assembly of microtubules around chromosomes. Here we show that interfering with the function of the human homologue of TPX2 in HeLa cells causes defects in microtubule organization during mitosis. Suppressing the expression of human TPX2 by RNA interference leads to the formation of two microtubule asters that do not interact and do not form a spindle. Our results suggest that in vivo, even in the presence of duplicated centrosomes, spindle formation requires the function of TPX2 to generate a stable bipolar spindle with overlapping antiparallel microtubule arrays. This indicates that chromosome-induced microtubule production is a general requirement for the formation of functional spindles in animal cells.
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Acknowledgements
We thank T. Zimmermann for help with confocal microscopes and image acquisition, and E. Nigg for sharing unpublished data. This work was funded by the European Molecular Biology Laboratory (EMBL). O.J.G. was supported in part by a Deutsche Forschungsgemeinschaft fellowship and in part by an EMBL postdoctoral fellowship.
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Gruss, O., Wittmann, M., Yokoyama, H. et al. Chromosome-induced microtubule assembly mediated by TPX2 is required for spindle formation in HeLa cells. Nat Cell Biol 4, 871–879 (2002). https://doi.org/10.1038/ncb870
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DOI: https://doi.org/10.1038/ncb870
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