Document Detail

Alteration of cell cycle timing and induction of surface instability in starfish blastomeres microinjected with antibodies to spectrin.
MedLine Citation:
PMID:  8948585     Owner:  NLM     Status:  MEDLINE    
Spectrin has been implicated in a variety of different processes during late embryogenesis, after transcription of the zygotic genome has been activated. However, relatively little is known about the role of maternally derived spectrin during the early cleavage divisions that give rise to a multicellular embryo. To investigate the role of spectrin in early development, we have microinjected anti-spectrin antibodies into Patiria miniata starfish embryos to inhibit the activity of the maternal pool of spectrin. Microinjection of affinity-purified anti-spectrin antibody, or low to moderate doses of F(ab) fragments, into one blastomere of a two-cell-stage embryo caused a dose-dependent, progressive increase in the length of the cell cycle compared to the uninjected control blastomere. The progeny of injected blastomeres were unable to participate in the formation of a blastula epithelium, instead forming a loose aggregate of cells that eventually stopped dividing. When division stopped, the cells formed surface protrusions and became motile. At high doses of either whole antibody or F(ab) fragments, cells initiated, but failed to complete, cytokinesis. Blastomeres injected with high doses of F(ab) fragments also failed to reform nuclei and underwent variable periods of cell cycle arrest up to 12 hr. Injected embryos stained with BODIPY-phallacidin exhibited extensive disruption of the cortical actin cytoskeleton. These results support previous studies implicating spectrin in stabilizing the cell surface and maintaining the organization of the cortical cytoskeleton. They further suggest that spectrin is not required for the initiation or contraction of the cleavage furrow, but functions in the completion of cytokinesis. Most surprisingly, however, the results demonstrate that inhibition of spectrin function alters cell cycle timing, suggesting that disruption of the actin cytoskeleton inhibits progression through the cell cycle.
G K Wong; D H Hoyle; D A Begg
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Developmental biology     Volume:  180     ISSN:  0012-1606     ISO Abbreviation:  Dev. Biol.     Publication Date:  1996 Nov 
Date Detail:
Created Date:  1997-01-21     Completed Date:  1997-01-21     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0372762     Medline TA:  Dev Biol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  199-212     Citation Subset:  IM    
Department of Anatomy and Cell Biology, Faculty of Medicine, University of Alberta, Edmonton, Canada.
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MeSH Terms
Biological Clocks
Blastomeres / cytology*,  physiology*
Cell Cycle*
Cell Nucleus / physiology,  ultrastructure
Embryo, Nonmammalian / physiology
Immunoglobulin Fab Fragments / administration & dosage,  pharmacology
Immunoglobulin G / administration & dosage,  pharmacology*
Spectrin / antagonists & inhibitors,  immunology,  physiology*
Starfish / embryology*
Time Factors
Reg. No./Substance:
0/Immunoglobulin Fab Fragments; 0/Immunoglobulin G; 12634-43-4/Spectrin

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

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