Document Detail


Ran GTPase cycle and importins alpha and beta are essential for spindle formation and nuclear envelope assembly in living Caenorhabditis elegans embryos.
MedLine Citation:
PMID:  12475958     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The small GTPase Ran has been found to play pivotal roles in several aspects of cell function. We have investigated the role of the Ran GTPase cycle in spindle formation and nuclear envelope assembly in dividing Caenorhabditis elegans embryos in real time. We found that Ran and its cofactors RanBP2, RanGAP, and RCC1 are all essential for reformation of the nuclear envelope after cell division. Reducing the expression of any of these components of the Ran GTPase cycle by RNAi leads to strong extranuclear clustering of integral nuclear envelope proteins and nucleoporins. Ran, RanBP2, and RanGAP are also required for building a mitotic spindle, whereas astral microtubules are normal in the absence of these proteins. RCC1(RNAi) embryos have similar abnormalities in the initial phase of spindle formation but eventually recover to form a bipolar spindle. Irregular chromatin structures and chromatin bridges due to spindle failure were frequently observed in embryos where the Ran cycle was perturbed. In addition, connection between the centrosomes and the male pronucleus, and thus centrosome positioning, depends upon the Ran cycle components. Finally, we have demonstrated that both IMA-2 and IMB-1, the homologues of vertebrate importin alpha and beta, are essential for both spindle assembly and nuclear formation in early embryos.
Authors:
Peter Askjaer; Vincent Galy; Eva Hannak; Iain W Mattaj
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Molecular biology of the cell     Volume:  13     ISSN:  1059-1524     ISO Abbreviation:  Mol. Biol. Cell     Publication Date:  2002 Dec 
Date Detail:
Created Date:  2002-12-11     Completed Date:  2003-07-29     Revised Date:  2013-04-18    
Medline Journal Info:
Nlm Unique ID:  9201390     Medline TA:  Mol Biol Cell     Country:  United States    
Other Details:
Languages:  eng     Pagination:  4355-70     Citation Subset:  IM    
Affiliation:
European Molecular Biology Laboratory, 69117 Heidelberg, Germany.
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MeSH Terms
Descriptor/Qualifier:
Aneuploidy
Animals
Caenorhabditis elegans
Caenorhabditis elegans Proteins / biosynthesis,  physiology*
Cell Nucleus / metabolism*
Centrosome / metabolism
Embryo, Nonmammalian
GTP Phosphohydrolases / metabolism
Hydrolysis
Karyopherins / biosynthesis,  physiology*
Microscopy, Fluorescence
Mitosis
Mitotic Spindle Apparatus / physiology*
Plasmids / metabolism
Protein Binding
RNA Interference
Time Factors
beta Karyopherins / biosynthesis,  physiology*
ran GTP-Binding Protein / metabolism*
Chemical
Reg. No./Substance:
0/Caenorhabditis elegans Proteins; 0/IMA-2 protein, C elegans; 0/IMB-1 protein, C elegans; 0/Karyopherins; 0/beta Karyopherins; EC 3.6.1.-/GTP Phosphohydrolases; EC 3.6.5.2/ran GTP-Binding Protein
Comments/Corrections
Erratum In:
Mol Biol Cell. 2004 Jan;15(1):preceding Table of Contents

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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