Authors: GÃ¶nczy P; Pichler S; Kirkham M; Hyman AA
Abstract: We have investigated the role of cytoplasmic dynein in microtubule organizing center (MTOC) positioning using RNA-mediated interference (RNAi) in Caenorhabditis elegans to deplete the product of the dynein heavy chain gene dhc-1. Analysis with time-lapse differential interference contrast microscopy and indirect immunofluorescence revealed that pronuclear migration and centrosome separation failed in one cell stage dhc-1 (RNAi) embryos. These phenotypes were also observed when the dynactin components p50/dynamitin or p150(Glued) were depleted with RNAi. Moreover, in 15% of dhc-1 (RNAi) embryos, centrosomes failed to remain in proximity of the male pronucleus. When dynein heavy chain function was diminished only partially with RNAi, centrosome separation took place, but orientation of the mitotic spindle was defective. Therefore, cytoplasmic dynein is required for multiple aspects of MTOC positioning in the one cell stage C. elegans embryo. In conjunction with our observation of cytoplasmic dynein distribution at the periphery of nuclei, these results lead us to propose a mechanism in which cytoplasmic dynein anchored on the nucleus drives centrosome separation.Keywords: Amino Acid Sequence; Animals; Antibodies/immunology; Biological Transport; Caenorhabditis elegans/cytology/drug effects/*embryology/metabolism; Cell Nucleus/*metabolism; Centrosome/*metabolism; Cytoplasm/*metabolism; Cytoplasmic Granules/metabolism; Dyneins/chemistry/genetics/immunology/*metabolism; Egg Yolk/cytology; Embryo, Nonmammalian/cytology/drug effects/metabolism; Female; Gene Silencing/drug effects; Helminth Proteins/genetics/metabolism; Male; Microtubule-Associated Proteins/genetics/metabolism; Mitotic Spindle Apparatus/metabolism; Models, Biological; Molecular Sequence Data; RNA, Double-Stranded/genetics/pharmacology; Time Factors
Journal: The Journal of cell biology
Date: Oct. 6, 1999
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GÃ¶nczy P, Pichler S, Kirkham M, Hyman AA (1999) Cytoplasmic dynein is required for distinct aspects of MTOC positioning, including centrosome separation, in the one cell stage Caenorhabditis elegans embryo. The Journal of cell biology 147: 135-50.