Publication Date:
2022-05-25
Description:
Author Posting. © The Author(s), 2009. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Current Biology 19 (2009): 1210-1215, doi:10.1016/j.cub.2009.05.061.
Description:
During animal cell division, a gradient of GTP-bound Ran is generated
around mitotic chromatin. It is generally accepted that this RanGTP
gradient is essential for organizing the spindle since it locally activates
critical spindle assembly factors. Here, we show in Xenopus egg
extract, where the gradient is best characterized, that spindles can
assemble in the absence of a RanGTP gradient. Gradient-free spindle
assembly occurred around sperm nuclei but not around chromatin-coated
beads and required the chromosomal passenger complex (CPC). Artificial
enrichment of CPC activity within hybrid bead arrays containing both
immobilized chromatin and the CPC supported local microtubule assembly
even in the absence of a RanGTP gradient. We conclude that RanGTP and
the CPC constitute the two major molecular signals that spatially promote
microtubule polymerization around chromatin. Furthermore, we
hypothesize that the two signals mainly originate from discreet physical
sites on the chromosomes to localize microtubule assembly around
chromatin: a RanGTP signal from any chromatin, and a CPC-dependent
signal predominantly generated from centromeric chromatin.
Description:
This work was supported by the American
Cancer Society (grant PF0711401 to T.J. Maresca), the National Cancer Institute
(grant CA078048-09 to T.J. Mitchison) and the National Institutes of Health (grant
F32GM080049 to J.C. Gatlin and grant GM24364 to E.D. Salmon).
Repository Name:
Woods Hole Open Access Server
Type:
Preprint
Format:
video/quicktime
Format:
application/pdf
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