The kinetically dominant assembly pathway for centrosomal asters in Caenorhabditis elegans is gamma-tubulin dependent

Autor: Hannak, E., Oegema, K., Kirkham, M., Gönczy, P., Habermann, B., Hyman, A. A.
Rok vydání: 2002
Předmět:
Helminth Proteins/genetics/metabolism
Dynein ATPase/genetics/metabolism
Fluorescent Antibody Technique
Sequence Homology
tbg-1
Centrosome/*metabolism
Microtubules
Medical and Health Sciences
Mitotic Spindle Apparatus
Tubulin
Tubulin/*deficiency/genetics
grip
Non-U.S. Gov't
Phylogeny
Microtubules/genetics/*metabolism
Helminth Proteins
Biological Sciences
Amino Acid
Phenotype
Mitotic Spindle Apparatus/genetics/*metabolism
Microtubule-Associated Proteins
Signal Transduction
microtubule
1.1 Normal biological development and functioning
Molecular Sequence Data
Mitosis
Down-Regulation
RNA/genetics
macromolecular substances
Spindle Apparatus
Mutation/*physiology
Research Support
Down-Regulation/physiology
Genetics
Animals
Point Mutation
Point Mutation/genetics
Mitosis/*physiology
Caenorhabditis elegans
Caenorhabditis elegans Proteins
Centrosome
Dyneins
Caenorhabditis elegans/*genetics/metabolism
Kinetics
Caenorhabditis elegans Proteins/genetics/metabolism
Mutation
Signal Transduction/genetics
RNA
Spc
Microtubule-Associated Proteins/genetics/metabolism
Generic health relevance
Developmental Biology
Zdroj: The Journal of cell biology, vol 157, iss 4
Popis: gamma-Tubulin-containing complexes are thought to nucleate and anchor centrosomal microtubules (MTs). Surprisingly, a recent study (Strome, S., J. Powers, M. Dunn, K. Reese, C.J. Malone, J. White, G. Seydoux, and W. Saxton. Mol. Biol. Cell. 12:1751-1764) showed that centrosomal asters form in Caenorhabditis elegans embryos depleted of gamma-tubulin by RNA-mediated interference (RNAi). Here, we investigate the nucleation and organization of centrosomal MT asters in C. elegans embryos severely compromised for gamma-tubulin function. We characterize embryos depleted of approximately 98% centrosomal gamma-tubulin by RNAi, embryos expressing a mutant form of gamma-tubulin, and embryos depleted of a gamma-tubulin-associated protein, CeGrip-1. In all cases, centrosomal asters fail to form during interphase but assemble as embryos enter mitosis. The formation of these mitotic asters does not require ZYG-9, a centrosomal MT-associated protein, or cytoplasmic dynein, a minus end-directed motor that contributes to self-organization of mitotic asters in other organisms. By kinetically monitoring MT regrowth from cold-treated mitotic centrosomes in vivo, we show that centrosomal nucleating activity is severely compromised by gamma-tubulin depletion. Thus, although unknown mechanisms can support partial assembly of mitotic centrosomal asters, gamma-tubulin is the kinetically dominant centrosomal MT nucleator.
Databáze: OpenAIRE
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