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Centrioles organize microtubules in two ways: either microtubules elongate from the centriole cylinder itself, forming a flagellum or a cilium ("template elongation"), or pericentriolar material assembles and nucleates a microtubule aster ("astral nucleation"). During spermatogenesis in most species, a motile flagellum elongates from one of the sperm centrioles, whereas after fertilization a large aster of microtubules forms around the sperm centrioles in the eggcytoplasm. Using Xenopus egg extracts we have developed an in vitro system to study this change in microtubule-organizing activity. An aster of microtubules forms around the centrioles of permeabilized frog sperm in egg extracts, but not in pure tubulin. However, when the sperm heads are incubated in the egg extract in the presence of nocodazole, they are able to nucleate a microtubule aster after isolation and incubation with pure calf brain tubulin. This provides a two-step assay that distinguishes between centrosome assembly and subsequent microtubule nucleation. We have studied several centrosomal antigens during centrosome assembly. The CTR2611 antigen is present in the spermhead in the peri-centriolar region. gamma-tubulin and certain phosphorylated epitopes appear in the centrosome only after incubation in the egg extract. gamma-tubulin is recruited from the egg extract and associated with electron-dense patches dispersed in a wide area around the centrioles. Immunodepletion of gamma-tubulin and associated molecules from the egg extract before spermhead incubation prevents the change in microtubule-organizing activity of the sperm heads. This suggests that gamma-tubulin and/or associated molecules play a key role in centrosome formation and activity.
Bacallao,
The subcellular organization of Madin-Darby canine kidney cells during the formation of a polarized epithelium.
1989, Pubmed
Bacallao,
The subcellular organization of Madin-Darby canine kidney cells during the formation of a polarized epithelium.
1989,
Pubmed Bailly,
p34cdc2 is located in both nucleus and cytoplasm; part is centrosomally associated at G2/M and enters vesicles at anaphase.
1989,
Pubmed Blow,
Initiation of DNA replication in nuclei and purified DNA by a cell-free extract of Xenopus eggs.
1986,
Pubmed
,
Xenbase Bornens,
Structural and chemical characterization of isolated centrosomes.
1987,
Pubmed
,
Xenbase Bré,
Effects of brain microtubule-associated proteins on microtubule dynamics and the nucleating activity of centrosomes.
1990,
Pubmed Bré,
Regulation of microtubule dynamics and nucleation during polarization in MDCK II cells.
1990,
Pubmed Buendia,
A centrosomal antigen localized on intermediate filaments and mitotic spindle poles.
1990,
Pubmed
,
Xenbase Buendia,
Regulation of the microtubule nucleating activity of centrosomes in Xenopus egg extracts: role of cyclin A-associated protein kinase.
1992,
Pubmed
,
Xenbase Burns,
Alpha-, beta-, and gamma-tubulins: sequence comparisons and structural constraints.
1991,
Pubmed Calarco-Gillam,
Centrosome development in early mouse embryos as defined by an autoantibody against pericentriolar material.
1983,
Pubmed Carlier,
Kinetic analysis of cooperativity in tubulin polymerization in the presence of guanosine di- or triphosphate nucleotides.
1978,
Pubmed Centonze,
Nucleation of microtubules from mitotic centrosomes is modulated by a phosphorylated epitope.
1990,
Pubmed Davis,
Monoclonal antibodies to mitotic cells.
1983,
Pubmed
,
Xenbase Erickson,
The role of subunit entropy in cooperative assembly. Nucleation of microtubules and other two-dimensional polymers.
1981,
Pubmed Evans,
Influence of the centrosome on the structure of nucleated microtubules.
1985,
Pubmed Felix,
A post-ribosomal supernatant from activated Xenopus eggs that displays post-translationally regulated oscillation of its cdc2+ mitotic kinase activity.
1989,
Pubmed
,
Xenbase Gard,
Centrosome duplication continues in cycloheximide-treated Xenopus blastulae in the absence of a detectable cell cycle.
1990,
Pubmed
,
Xenbase Gerhart,
Cell cycle dynamics of an M-phase-specific cytoplasmic factor in Xenopus laevis oocytes and eggs.
1984,
Pubmed
,
Xenbase Gueth-Hallonet,
gamma-Tubulin is present in acentriolar MTOCs during early mouse development.
1993,
Pubmed Horio,
The fission yeast gamma-tubulin is essential for mitosis and is localized at microtubule organizing centers.
1991,
Pubmed Hyman,
Preparation of modified tubulins.
1991,
Pubmed Joshi,
Gamma-tubulin is a centrosomal protein required for cell cycle-dependent microtubule nucleation.
1992,
Pubmed Julian,
gamma-Tubulin participates in the formation of the midbody during cytokinesis in mammalian cells.
1993,
Pubmed
,
Xenbase Kalt,
Molecular components of the centrosome.
1993,
Pubmed Keryer,
A high-affinity binding protein for the regulatory subunit of cAMP-dependent protein kinase II in the centrosome of human cells.
1993,
Pubmed Kirschner,
Beyond self-assembly: from microtubules to morphogenesis.
1986,
Pubmed Kuriyama,
Cytasters induced within unfertilized sea-urchin eggs.
1983,
Pubmed Kuriyama,
Activity and stability of centrosomes in Chinese hamster ovary cells in nucleation of microtubules in vitro.
1984,
Pubmed Kuriyama,
The centriolar complex isolated from starfish spermatozoa.
1981,
Pubmed Leiss,
Association of cyclin-bound p34cdc2 with subcellular structures in xenopus eggs.
1992,
Pubmed
,
Xenbase Liu,
A gamma-tubulin-related protein associated with the microtubule arrays of higher plants in a cell cycle-dependent manner.
1993,
Pubmed Maller,
Spindle formation and cleavage in Xenopus eggs injected with centriole-containing fractions from sperm.
1976,
Pubmed
,
Xenbase Manes,
On the possibility of sperm aster involvement in dorso-ventral polarization and pronuclear migration in the amphibian egg.
1977,
Pubmed Maro,
Non-spindle microtubule organizing centers in metaphase II-arrested mouse oocytes.
1985,
Pubmed Masuda,
In vitro microtubule-nucleating activity of spindle pole bodies in fission yeast Schizosaccharomyces pombe: cell cycle-dependent activation in xenopus cell-free extracts.
1992,
Pubmed
,
Xenbase Mitchison,
Microtubule assembly nucleated by isolated centrosomes.
,
Pubmed Muresan,
Gamma-tubulin in differentiated cell types: localization in the vicinity of basal bodies in retinal photoreceptors and ciliated epithelia.
1993,
Pubmed Newport,
A major developmental transition in early Xenopus embryos: II. Control of the onset of transcription.
1982,
Pubmed
,
Xenbase Oakley,
Gamma-tubulin is a component of the spindle pole body that is essential for microtubule function in Aspergillus nidulans.
1990,
Pubmed Oakley,
Gamma-tubulin: the microtubule organizer?
1992,
Pubmed Palacios,
Gamma-tubulin reorganization during mouse fertilization and early development.
1993,
Pubmed Price,
Redistribution of the nuclear mitotic apparatus protein (NuMA) during mitosis and nuclear assembly. Properties of purified NuMA protein.
1986,
Pubmed Raff,
Drosophila gamma-tubulin is part of a complex containing two previously identified centrosomal MAPs.
1993,
Pubmed Sager,
A novel mitotic spindle pole component that originates from the cytoplasm during prophase.
1986,
Pubmed Shelanski,
Microtubule assembly in the absence of added nucleotides.
1973,
Pubmed Stearns,
Gamma-tubulin is a highly conserved component of the centrosome.
1991,
Pubmed
,
Xenbase Tucker,
A cell surface-associated centrosomal layer of microtubule-organizing material in the inner pillar cell of the mouse cochlea.
1992,
Pubmed Ulloa,
Heterogeneity in the phosphorylation of microtubule-associated protein MAP1B during rat brain development.
1993,
Pubmed Ulloa,
Depletion of casein kinase II by antisense oligonucleotide prevents neuritogenesis in neuroblastoma cells.
1993,
Pubmed Vandre,
Phosphoproteins are components of mitotic microtubule organizing centers.
1984,
Pubmed Verde,
Regulation of microtubule dynamics by cdc2 protein kinase in cell-free extracts of Xenopus eggs.
1990,
Pubmed
,
Xenbase Verlhac,
MAP kinase becomes stably activated at metaphase and is associated with microtubule-organizing centers during meiotic maturation of mouse oocytes.
1993,
Pubmed Voter,
The kinetics of microtubule assembly. Evidence for a two-stage nucleation mechanism.
1984,
Pubmed Wade,
Cryoelectron microscopy of microtubules.
1993,
Pubmed Weingarten,
A protein factor essential for microtubule assembly.
1975,
Pubmed Zheng,
Gamma-tubulin is present in Drosophila melanogaster and Homo sapiens and is associated with the centrosome.
1991,
Pubmed
