Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
???displayArticle.abstract???
We have investigated the differences in microtubule assembly in cytoplasm from Xenopus oocytes and eggs in vitro. Extracts of activated eggs could be prepared that assembled extensive microtubule networks in vitro using Tetrahymena axonemes or mammalian centrosomes as nucleation centers. Assembly occurred predominantly from the plus-end of the microtubule with a rate constant of 2 microns.min-1.microM-1 (57 s-1.microM-1). At the in vivo tubulin concentration, this corresponds to the extraordinarily high rate of 40-50 microns.min-1. Microtubule disassembly rates in these extracts were -4.5 microns.min-1 (128 s-1) at the plus-end and -6.9 microns.min-1 (196 s-1) at the minus-end. The critical concentration for plus-end microtubule assembly was 0.4 microM. These extracts also promoted the plus-end assembly of microtubules from bovine brain tubulin, suggesting the presence of an assembly promoting factor in the egg. In contrast to activated eggs, assembly was never observed in extracts prepared from oocytes, even at tubulin concentrations as high as 20 microM. Addition of oocyte extract to egg extracts or to purified brain tubulin inhibited microtubule assembly. These results suggest that there is a plus-end-specific inhibitor of microtubule assembly in the oocyte and a plus-end-specific promoter of assembly in the eggs. These factors may serve to regulate microtubule assembly during early development in Xenopus.
Allen,
Structural polarity and directional growth of microtubules of Chlamydomonas flagella.
1974, Pubmed
Allen,
Structural polarity and directional growth of microtubules of Chlamydomonas flagella.
1974,
Pubmed Bradford,
A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding.
1976,
Pubmed Bryan,
Inhibition of tubulin assembly by RNA and other polyanions: evidence for a required protein.
1975,
Pubmed Detrich,
Purification, characterization, and assembly properties of tubulin from unfertilized eggs of the sea urchin Strongylocentrotus purpuratus.
1983,
Pubmed Elinson,
Changes in levels of polymeric tubulin associated with activation and dorsoventral polarization of the frog egg.
1985,
Pubmed
,
Xenbase Evans,
Influence of the centrosome on the structure of nucleated microtubules.
1985,
Pubmed Gard,
A microtubule-associated protein from Xenopus eggs that specifically promotes assembly at the plus-end.
1987,
Pubmed
,
Xenbase Gerhart,
Cell cycle dynamics of an M-phase-specific cytoplasmic factor in Xenopus laevis oocytes and eggs.
1984,
Pubmed
,
Xenbase Heidemann,
Microtubules in immature oocytes of Xenopus laevis.
1985,
Pubmed
,
Xenbase Heidemann,
The effect of taxol on living eggs of Xenopus laevis.
1980,
Pubmed
,
Xenbase Heidemann,
Aster formation in eggs of Xenopus laevis. Induction by isolated basal bodies.
1975,
Pubmed
,
Xenbase Karsenti,
Interconversion of metaphase and interphase microtubule arrays, as studied by the injection of centrosomes and nuclei into Xenopus eggs.
1984,
Pubmed
,
Xenbase Keller,
Strongylocentrotus purpuratus spindle tubulin. I. Characteristics of its polymerization and depolymerization in vitro.
1982,
Pubmed Manes,
On the possibility of sperm aster involvement in dorso-ventral polarization and pronuclear migration in the amphibian egg.
1977,
Pubmed Mitchison,
Dynamic instability of microtubule growth.
,
Pubmed Mitchison,
Microtubule assembly nucleated by isolated centrosomes.
,
Pubmed Newport,
A major developmental transition in early Xenopus embryos: I. characterization and timing of cellular changes at the midblastula stage.
1982,
Pubmed
,
Xenbase Olmsted,
Microtubule-associated proteins.
1986,
Pubmed Schulze,
Microtubule dynamics in interphase cells.
1986,
Pubmed Suprenant,
Purification and characterization of oocyte cytoplasmic tubulin and meiotic spindle tubulin of the surf clam Spisula solidissima.
1984,
Pubmed Suprenant,
Cytoplasmic tubulin from the unfertilized sea urchin egg: II. Variation of the intrinsic calcium sensitivity of Strongylocentrotus purpuratus egg tubulin as a function of temperature and brain microtubule-associated proteins.
1984,
Pubmed Tilney,
Actin from Thyone sperm assembles on only one end of an actin filament: a behavior regulated by profilin.
1983,
Pubmed Weisenberg,
In vitro polymerization of microtubules into asters and spindles in homogenates of surf clam eggs.
1975,
Pubmed
