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.
Simulation of the fertilization Ca2+ wave in Xenopus laevis eggs.
Wagner J, Li YX, Pearson J, Keizer J.
???displayArticle.abstract???
In the preceding paper Fontanilla and Nuccitelli (Biophysical Journal 75:2079-2087 (1998)) present detailed measurements of the shape and speed of the fertilization Ca2+ wave in Xenopus laevis eggs. In order to help interpret their results, we develop here a computational technique based on the finite element method that allows us to carry out realistic simulations of the fertilization wave. Our simulations support the hypothesis that the physiological state of the mature egg is bistable, i.e., that its cytoplasm can accommodate two alternative physiological Ca2+ concentrations: a low concentration characteristic of the prefertilization state and a greatly elevated concentration characteristic of the state following the passage of the wave. We explore this hypothesis by assuming that the bistability is due to the release and re-uptake properties of the endoplasmic reticulum (ER) as determined by inositol trisphosphate (IP3) receptor/Ca2+ channels and sarcoendoplasmic reticulum calcium ATPase (SERCA) pumps. When combined with buffered diffusion of Ca2+ in the cytoplasm, our simulations show that inhomogeneities in the Ca2+ release properties near the plasma membrane are required to explain the temporal and spatial dependences of the shape and speed of these waves. Our results are consistent with an elevated IP3 concentration near the plasma membrane in the unfertilized egg that is augmented significantly near the site of fertilization. These gradients are essential in determining the concave shape of the Ca2+ fertilization wave front.
Allbritton,
Range of messenger action of calcium ion and inositol 1,4,5-trisphosphate.
1992, Pubmed,
Xenbase
Allbritton,
Range of messenger action of calcium ion and inositol 1,4,5-trisphosphate.
1992,
Pubmed
,
Xenbase Atri,
A single-pool model for intracellular calcium oscillations and waves in the Xenopus laevis oocyte.
1993,
Pubmed
,
Xenbase Babcock,
Mitochondrial participation in the intracellular Ca2+ network.
1997,
Pubmed Berridge,
Inositol trisphosphate and calcium signalling.
1993,
Pubmed Bezprozvanny,
Bell-shaped calcium-response curves of Ins(1,4,5)P3- and calcium-gated channels from endoplasmic reticulum of cerebellum.
1991,
Pubmed Busa,
Activation of frog (Xenopus laevis) eggs by inositol trisphosphate. I. Characterization of Ca2+ release from intracellular stores.
1985,
Pubmed
,
Xenbase Campanella,
The modifications of cortical endoplasmic reticulum during in vitro maturation of Xenopus laevis oocytes and its involvement in cortical granule exocytosis.
1984,
Pubmed
,
Xenbase Charbonneau,
The onset of activation responsiveness during maturation coincides with the formation of the cortical endoplasmic reticulum in oocytes of Xenopus laevis.
1984,
Pubmed
,
Xenbase DeLisle,
Inositol trisphosphate is required for the propagation of calcium waves in Xenopus oocytes.
1992,
Pubmed
,
Xenbase De Young,
A single-pool inositol 1,4,5-trisphosphate-receptor-based model for agonist-stimulated oscillations in Ca2+ concentration.
1992,
Pubmed Ferrell,
The biochemical basis of an all-or-none cell fate switch in Xenopus oocytes.
1998,
Pubmed
,
Xenbase Finch,
Calcium as a coagonist of inositol 1,4,5-trisphosphate-induced calcium release.
1991,
Pubmed Fontanilla,
Characterization of the sperm-induced calcium wave in Xenopus eggs using confocal microscopy.
1998,
Pubmed
,
Xenbase Iino,
Biphasic Ca2+ dependence of inositol 1,4,5-trisphosphate-induced Ca release in smooth muscle cells of the guinea pig taenia caeci.
1990,
Pubmed Jaffe,
The path of calcium in cytosolic calcium oscillations: a unifying hypothesis.
1991,
Pubmed Jafri,
Diffusion of inositol 1,4,5-trisphosphate but not Ca2+ is necessary for a class of inositol 1,4,5-trisphosphate-induced Ca2+ waves.
1994,
Pubmed Jafri,
On the roles of Ca2+ diffusion, Ca2+ buffers, and the endoplasmic reticulum in IP3-induced Ca2+ waves.
1995,
Pubmed Jouaville,
Synchronization of calcium waves by mitochondrial substrates in Xenopus laevis oocytes.
1995,
Pubmed
,
Xenbase Kaftan,
Inositol 1,4,5-trisphosphate (InsP3) and calcium interact to increase the dynamic range of InsP3 receptor-dependent calcium signaling.
1997,
Pubmed Keizer,
InsP3-induced Ca2+ excitability of the endoplasmic reticulum.
1995,
Pubmed
,
Xenbase Lechleiter,
Molecular mechanisms of intracellular calcium excitability in X. laevis oocytes.
1992,
Pubmed
,
Xenbase Li,
Equations for InsP3 receptor-mediated [Ca2+]i oscillations derived from a detailed kinetic model: a Hodgkin-Huxley like formalism.
1994,
Pubmed Marshall,
Regulation of inositol 1,4,5-trisphosphate receptors.
1993,
Pubmed Murray,
Patient assessment in the postanesthesia care unit: a critical care approach.
1989,
Pubmed Nuccitelli,
The sperm-induced Ca2+ wave following fertilization of the Xenopus egg requires the production of Ins(1, 4, 5)P3.
1993,
Pubmed
,
Xenbase Nuccitelli,
How do sperm activate eggs?
1991,
Pubmed Parker,
Inhibition by Ca2+ of inositol trisphosphate-mediated Ca2+ liberation: a possible mechanism for oscillatory release of Ca2+.
1990,
Pubmed
,
Xenbase Parys,
Isolation, characterization, and localization of the inositol 1,4,5-trisphosphate receptor protein in Xenopus laevis oocytes.
1992,
Pubmed
,
Xenbase Ridgway,
Free calcium increases explosively in activating medaka eggs.
1977,
Pubmed Schaff,
A general computational framework for modeling cellular structure and function.
1997,
Pubmed Sims,
Metabolism of inositol 1,4,5-trisphosphate and inositol 1,3,4,5-tetrakisphosphate by the oocytes of Xenopus laevis.
1998,
Pubmed
,
Xenbase Snow,
Fertilization stimulates an increase in inositol trisphosphate and inositol lipid levels in Xenopus eggs.
1996,
Pubmed
,
Xenbase Taylor,
Oscillations in intracellular free calcium induced by spermatozoa in human oocytes at fertilization.
1993,
Pubmed Terasaki,
Structural change of the endoplasmic reticulum during fertilization: evidence for loss of membrane continuity using the green fluorescent protein.
1996,
Pubmed Terasaki,
Continuous network of endoplasmic reticulum in cerebellar Purkinje neurons.
1994,
Pubmed Wagner,
Effects of rapid buffers on Ca2+ diffusion and Ca2+ oscillations.
1994,
Pubmed Watras,
Inositol 1,4,5-trisphosphate-gated channels in cerebellum: presence of multiple conductance states.
1991,
Pubmed Yim,
Highly polarized EGF receptor tyrosine kinase activity initiates egg activation in Xenopus.
1994,
Pubmed
,
Xenbase
