Central spindle self-organization and cytokinesis in artificially activated sea urchin eggs
Central spindle self-organization and cytokinesis in artificially activated sea urchin eggs
Date
2016-04
Authors
Henson, John H.
Buckley, Mary W.
Yeterian, Mesrob
Weeks, Richard M.
Simerly, Calvin R.
Shuster, Charles B.
Buckley, Mary W.
Yeterian, Mesrob
Weeks, Richard M.
Simerly, Calvin R.
Shuster, Charles B.
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Abstract
The ability of microtubules of the mitotic apparatus
to control the positioning and initiation of the cleavage
furrow during cytokinesis was first established from
studies on early echinoderm embryos. However, the identity
of the microtubule population that imparts cytokinetic signaling
is unclear. The two main––and not necessarily mutually
exclusive–– candidates are the central spindle and the
astral rays. In the present study, we examined cytokinesis in
ammonia-activated sea urchin eggs, which lack paternally
derived centrosomes and undergo mitosis mediated by unusual
anastral, bipolar mini-spindles. Live cell imaging and
immunolabeling for microtubules and the centralspindlin
constituent and kinesin-related protein, MKLP1, demonstrated
that furrowing in ammonia-activated eggs was associated
with aligned arrays of centralspindlin-linked, opposed
bundles of antiparallel microtubules. These autonomous, zipper-
like arrays were not associated with a mitotic apparatus,
but did possess characteristics similar to the central spindle
region of control, fertilized embryos. Our results highlight the
self-organizing nature of the central spindle region and its
ability to induce cytokinesis-like furrowing, even in the absence
of a complete mitotic apparatus.
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Author Posting. © Marine Biological Laboratory, 2016. This article is posted here by permission of Marine Biological Laboratory for personal use, not for redistribution. The definitive version was published in Biological Bulletin 230, no.2 (2016): 85-95.
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Biological Bulletin 230, no.2 (2016): 85-95