Document Detail


A model for cleavage plane determination in early amphibian and fish embryos.
MedLine Citation:
PMID:  21055946     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Current models for cleavage plane determination propose that metaphase spindles are positioned and oriented by interactions of their astral microtubules with the cellular cortex, followed by cleavage in the plane of the metaphase plate [1, 2]. We show that in early frog and fish embryos, where cells are unusually large, astral microtubules in metaphase are too short to position and orient the spindle. Rather, the preceding interphase aster centers and orients a pair of centrosomes prior to nuclear envelope breakdown, and the spindle assembles between these prepositioned centrosomes. Interphase asters center and orient centrosomes with dynein-mediated pulling forces. These forces act before astral microtubules contact the cortex; thus, dynein must pull from sites in the cytoplasm, not the cell cortex as is usually proposed for smaller cells. Aster shape is determined by interactions of the expanding periphery with the cell cortex or with an interaction zone that forms between sister-asters in telophase. We propose a model to explain cleavage plane geometry in which the length of astral microtubules is limited by interaction with these boundaries, causing length asymmetries. Dynein anchored in the cytoplasm then generates length-dependent pulling forces, which move and orient centrosomes.
Authors:
Martin Wühr; Edwin S Tan; Sandra K Parker; H William Detrich; Timothy J Mitchison
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2010-11-04
Journal Detail:
Title:  Current biology : CB     Volume:  20     ISSN:  1879-0445     ISO Abbreviation:  Curr. Biol.     Publication Date:  2010 Nov 
Date Detail:
Created Date:  2010-11-24     Completed Date:  2011-04-18     Revised Date:  2014-09-16    
Medline Journal Info:
Nlm Unique ID:  9107782     Medline TA:  Curr Biol     Country:  England    
Other Details:
Languages:  eng     Pagination:  2040-5     Citation Subset:  IM    
Copyright Information:
Copyright © 2010 Elsevier Ltd. All rights reserved.
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MeSH Terms
Descriptor/Qualifier:
Animals
Cell Division*
Centrosome / ultrastructure
Embryo, Nonmammalian / cytology*,  ultrastructure
Embryonic Development
Female
Fertilization
Male
Metaphase
Microtubules / ultrastructure
Models, Biological*
Spermatozoa / ultrastructure
Spindle Apparatus / metabolism,  ultrastructure
Xenopus laevis
Zebrafish / embryology
Grant Support
ID/Acronym/Agency:
GM39565/GM/NIGMS NIH HHS; R01 GM039565/GM/NIGMS NIH HHS; R01 GM039565-23/GM/NIGMS NIH HHS
Comments/Corrections

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