Document Detail


Drosophila parthenogenesis: a model for de novo centrosome assembly.
MedLine Citation:
PMID:  12921733     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The Drosophila egg contains all the components required to properly execute the early mitotic divisions but is unable to assemble a functional centrosome without a sperm-provided basal body. We show that 65% of unfertilized eggs obtained from a laboratory strain of Drosophila mercatorum can spontaneously assemble a number of cytoplasmic asters after activation, most of them duplicating in a cell cycle-dependent manner. Such asters are formed by a polarized array of microtubules that have their Asp-associated minus-ends converging at a main focus, where centrioles and typical centrosomal antigens are found. Aster assembly is spatially restricted to the anterior region of the oocyte. When fertilized, the parthenogenetic egg forms the poles of the gonomeric spindle by using the sperm-provided basal body, despite the presence within the same cytoplasm of maternal centrosomes. Thirty-five percent of parthenogenetic eggs and all unfertilized and fertilized eggs from the sibling bisexually reproducing D. mercatorum strain do not contain cytoplasmic asters. Thus, the Drosophila eggs have the potential for de novo formation of functional centrosomes independent of preexisting centrioles, but some control mechanisms preventing their spontaneous assembly must exist. We speculate that the release of the block preventing centrosome self-assembly could be a landmark for ensuring parthenogenetic reproduction.
Authors:
Maria Giovanna Riparbelli; Giuliano Callaini
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Developmental biology     Volume:  260     ISSN:  0012-1606     ISO Abbreviation:  Dev. Biol.     Publication Date:  2003 Aug 
Date Detail:
Created Date:  2003-08-18     Completed Date:  2003-10-03     Revised Date:  2003-11-14    
Medline Journal Info:
Nlm Unique ID:  0372762     Medline TA:  Dev Biol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  298-313     Citation Subset:  IM    
Affiliation:
University of Siena, Department of Evolutionary Biology, Via A Moro 4, I-53100 Siena, Italy.
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MeSH Terms
Descriptor/Qualifier:
Animals
Centrosome / physiology*
Cytoplasm / physiology
Drosophila / physiology*
Female
Fertilization
Male
Meiosis
Mitotic Spindle Apparatus / physiology
Oocytes / cytology,  physiology
Ovum / cytology,  physiology
Parthenogenesis / physiology*
Spermatozoa / cytology,  physiology

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


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