Elsevier

Developmental Biology

Volume 149, Issue 1, January 1992, Pages 80-89
Developmental Biology

Full paper
Repetitive calcium transients and the role of calcium in exocytosis and cell cycle activation in the mouse egg

https://doi.org/10.1016/0012-1606(92)90265-IGet rights and content

Abstract

The role of calcium in cortical granule exocytosis and activation of the cell cycle at fertilization was examined in the mouse egg using the calcium chelator BAPTA (1,2-bis(o-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid) and the fluorescent calcium indicator fluo-3. BAPTA and fluo-3 were introduced into zona-free mouse eggs by a 30-min incubation with 0.01–50 μM BAPTA acetoxymethyl ester (AM) and/or 1–20 μM fluo-3 AM prior to in vitro fertilization. Incubation of eggs in ⩾5.0 μM BAPTA AM inhibited cortical granule exocytosis in all cases. Introduction of the calcium chelator into the egg blocked second polar body formation at ⩾1.0 μM BAPTA AM. Sperm entry occurred in all eggs regardless of the BAPTA AM concentration. Sperm induce a large transient increase in calcium lasting 2.3 ± 0.6 min, followed by repetitive transients lasting 0.5 ± 0.1 min and occurring at 3.4 ± 1.4-min intervals. Incubation with ⩾5.0 μM BAPTA AM inhibited all calcium transients. Introduction of BAPTA also inhibited calcium transients, exocytosis, and the resumption of meiosis following application of the calcium ionophore A23187 or SrCl2, which activate eggs. These results demonstrate that the calcium increase at fertilization is required for cortical granule exocytosis and resumption of the cell cycle in a mammalian egg.

References (51)

  • A. Minta et al.

    Fluorescent indicators for cytosolic calcium based on rhodamine and fluorescein chromophores

    J. Biol. Chem

    (1989)
  • S. Miyazaki

    Repetitive calcium transients in hamster oocytes

    Cell Calcium

    (1991)
  • S. Miyazaki et al.

    Temporal and spatial dynamics of the periodic increase in intracellular free calcium at fertilization of golden hamster eggs

    Dev. Biol

    (1986)
  • J.E. Speksnijder et al.

    Periodic calcium waves cross ascidian eggs after fertilization

    Dev. Biol

    (1990)
  • P.R. Turner et al.

    G-proteins and the regulation of oocyte maturation and fertilization

  • M.J. Whitaker et al.

    Ionic signaling in the sea urchin egg at fertilization

  • D.G. Whittingham et al.

    The involvement of calcium in the activation of mammalian oocytes

    Exp. Cell Res

    (1978)
  • R.S. Zucker et al.

    Prevention of the cortical reaction in fertilized sea urchin eggs by injection of calcium-chelating ligands

    Biochim. Biophys. Acta

    (1978)
  • W.M. Bement et al.

    Protein kinase C acts down-stream of calcium at entry into the first mitotic interphase of Xenopus laevis

    Cell Reg

    (1990)
  • M.J. Berridge et al.

    Cytosolic calcium oscillators

    FASEB J

    (1988)
  • G.N. Cherr et al.

    Localization of cortical granule constituents before and after exocytosis in the hamster egg

    J. Exp. Zool

    (1988)
  • R. Colonna et al.

    Effects of protein kinase C stimulation and free Ca2+ rise in mammalian egg activation

    Gamete Res

    (1989)
  • J.C. Conover et al.

    Pre-loading of mouse oocytes with DNA-specific fluorochrome (Hoechst 33342) permits rapid detection of sperm-oocyte fusion

    J. Reprod. Fertil

    (1988)
  • D.G. Cran et al.

    Initiation of the cortical reaction in hamster and sheep oocytes in response to inositol trisphosphate

    J. Cell Sci

    (1988)
  • K.S.R. Cuthbertson

    Parthenogenetic activation of mouse oocytes in vitro with ethanol and benzyl alcohol

    J. Exp. Zool

    (1983)
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    This work was supported by a grant from the National Institute of Child Health and Human Development (HD 26032) to D. Kline.

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