Abstract
At fertilization, an increase of cytosolic calcium ions (Ca2+) triggers various activation responses in animal eggs1,2. In vertebrates, these responses include exit from metaphase arrest in meiosis II (MII exit) and cortical remodelling initiated by cortical granule exocytosis. Although the essential requirement of Ca2+/calmodulin-dependent protein kinase II for inducing MII exit has been documented3, a role of the Ca2+/calmodulin-dependent protein phosphatase calcineurin in egg activation has not been investigated. Here we show, using cell-free extracts from unfertilized eggs of Xenopus laevis, that calcineurin is transiently activated immediately after Ca2+ addition to a concentration that induces MII exit. When calcineurin activation is inhibited, cyclin-dependent kinase 1 (Cdk1) inactivation by means of cyclin B degradation is prevented and sperm chromatin incubated in the extracts remains condensed. Similarly, if calcineurin is inhibited in intact eggs, MII exit on egg activation is prevented. In addition, the activation contraction4 in the cortex is suppressed whereas cortical granule exocytosis occurs. We further demonstrate that, when a high level of calcineurin activity is maintained after activation, growth of sperm asters is prevented in egg extracts and, consistently, migration of male and female pronuclei towards each other is hindered in fertilized eggs. Thus, both activation and the subsequent inactivation of calcineurin in fertilized eggs are crucial for the commencement of vertebrate embryonic development.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Buy this article
- Purchase on SpringerLink
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
References
Stricker, S. A. Comparative biology of calcium signaling during fertilization and egg activation in animals. Dev. Biol. 211, 157–176 (1999)
Whitaker, M. Calcium at fertilization and in early development. Physiol. Rev. 86, 25–88 (2006)
Lorca, T. et al. Calmodulin-dependent protein kinase II mediates inactivation of MPF and CSF upon fertilization of Xenopus eggs. Nature 366, 270–273 (1993)
Palecek, J., Ubbels, G. A. & Rzehak, K. Changes of the external and internal pigment pattern upon fertilization in the egg of Xenopus laevis. J. Embryol. Exp. Morphol. 45, 203–214 (1978)
Masui, Y. The elusive cytostatic factor in the animal egg. Nature Rev. Mol. Cell Biol. 1, 228–232 (2000)
Hedrick, J. L. & Nishihara, T. Structure and function of the extracellular matrix of anuran eggs. J. Electron Microsc. Tech. 17, 319–335 (1991)
Larabell, C. & Chandler, D. E. Fertilization-induced changes in the vitelline envelope of echinoderm and amphibian eggs: self-assembly of an extracellular matrix. J. Electron Microsc. Tech. 17, 294–318 (1991)
Christensen, K., Sauterer, R. & Merriam, R. W. Role of soluble myosin in cortical contractions of Xenopus eggs. Nature 310, 150–151 (1984)
Capco, D. G., Tutnick, J. M. & Bement, W. M. The role of protein kinase C in reorganization of the cortical cytoskeleton during the transition from oocyte to fertilization-competent egg. J. Exp. Zool. 264, 395–405 (1992)
Hamaguchi, M. S. & Hiramoto, Y. Analysis of the role of astral rays in pronuclear migration by the colcemid–UV method. Dev. Growth Differ. 28, 143–156 (1986)
Navara, C. S., First, N. L. & Schatten, G. Microtubule organization in the cow during fertilization, polyspermy, parthenogenesis, and nuclear transfer: the role of the sperm aster. Dev. Biol. 162, 29–40 (1994)
Reinsch, S. & Karsenti, E. Movement of nuclei along microtubules in Xenopus egg extracts. Curr. Biol. 7, 211–214 (1997)
Jaffe, L. F. Sources of calcium in egg activation: a review and hypothesis. Dev. Biol. 99, 265–276 (1983)
Sardet, C., Dumollard, R. & McDougall, A. Signals and calcium waves at fertilization. Semin. Cell Dev. Biol. 17, 223–225 (2006)
Bement, W. M. & Capco, D. G. Protein kinase C acts downstream of calcium at entry into the first mitotic interphase of Xenopus laevis. Cell Regul. 1, 315–326 (1990)
Rauh, N. R., Schmidt, A., Bormann, J., Nigg, E. A. & Mayer, T. U. Calcium triggers exit from meiosis II by targeting the APC/C inhibitor XErp1 for degradation. Nature 437, 1048–1052 (2005)
Liu, J. & Maller, J. L. Calcium elevation at fertilization coordinates phosphorylation of XErp1/Emi2 by Plx1 and CaMK II to release metaphase arrest by cytostatic factor. Curr. Biol. 15, 1458–1468 (2005)
Hansen, D. V., Tung, J. J. & Jackson, P. K. CaMKII and Polo-like kinase 1 sequentially phosphorylate the cytostatic factor Emi2/XErp1 to trigger its destruction and meiotic exit. Proc. Natl Acad. Sci. USA 103, 608–613 (2006)
Rusnak, F. & Mertz, P. Calcineurin: form and function. Physiol. Rev. 80, 1483–1521 (2000)
Lohka, M. J. & Maller, J. L. Induction of nuclear envelope breakdown, chromosome condensation, and spindle formation in cell-free extracts. J. Cell Biol. 101, 518–523 (1985)
Murray, A. W., Solomon, M. J. & Kirschner, M. W. The role of cyclin synthesis and degradation in the control of maturation promoting factor activity. Nature 339, 280–286 (1989)
Blumenthal, D. K., Takio, K., Hansen, R. S. & Krebs, E. G. Dephosphorylation of cAMP-dependent protein kinase regulatory subunit (type II) by calmodulin-dependent protein phosphatase. Determinants of substrate specificity. J. Biol. Chem. 261, 8140–8145 (1986)
Hanson, P. I., Kapiloff, M. S., Lou, L. L., Rosenfeld, M. G. & Schulman, H. Expression of a multifunctional Ca2+/calmodulin-dependent protein kinase and mutational analysis of its autoregulation. Neuron 3, 59–70 (1989)
Colbran, R. J., Fong, Y. L., Schworer, C. M. & Soderling, T. R. Regulatory interactions of the calmodulin-binding, inhibitory, and autophosphorylation domains of Ca2+/calmodulin-dependent protein kinase II. J. Biol. Chem. 263, 18145–18151 (1988)
Schmidt, A. et al. Xenopus polo-like kinase Plx1 regulates XErp1, a novel inhibitor of APC/C activity. Genes Dev. 19, 502–513 (2005)
Nishiyama, T., Ohsumi, K. & Kishimoto, T. Phosphorylation of Erp1 by p90rsk is required for cytostatic factor arrest in Xenopus laevis eggs. Nature 446, 1096–1099 (2007)
Guardavaccaro, D. et al. Control of meiotic and mitotic progression by the F box protein β-Trcp1 in vivo. Dev. Cell 4, 799–812 (2003)
Iwabuchi, M., Ohsumi, K., Yamamoto, T. M., Sawada, W. & Kishimoto, T. Residual Cdc2 activity remaining at meiosis I exit is essential for meiotic M–M transition in Xenopus oocyte extracts. EMBO J. 19, 4513–4523 (2000)
Sultana, F., Yokoe, A., Ito, Y., Mao, K. M. & Yoshizaki, N. The peri-albumen layer: a novel structure in the envelopes of an avian egg. J. Anat. 203, 115–122 (2003)
Wangh, L. J. Injection of Xenopus eggs before activation, achieved by control of extracellular factors, improves plasmid DNA replication after activation. J. Cell Sci. 93, 1–8 (1989)
Newport, J. & Kirschner, M. A major developmental transition in early Xenopus embryos: I. characterization and timing of cellular changes at the midblastula stage. Cell 30, 675–686 (1982)
Murray, A. W., Solomon, M. J. & Kirschner, M. W. The role of cyclin synthesis and degradation in the control of maturation promoting factor activity. Nature 339, 280–286 (1989)
Yamamoto, T. M., Iwabuchi, M., Ohsumi, K. & Kishimoto, T. APC/C-Cdc20-mediated degradation of cyclin B participates in CSF arrest in unfertilized Xenopus eggs. Dev. Biol. 279, 345–355 (2005)
Mackintosh, C. & Moorhead, G. Protein Phosphorylation: A Practical Approach (ed. Hardie, D. G.) 153–181 (Oxford Univ. Press, Oxford, 1999)
Ohsumi, K., Yamamoto, T. M. & Iwabuchi, M. Oocyte extracts for the study of meiotic M–M transition. Methods Mol. Biol. 322, 445–458 (2006)
Uto, K., Nakajo, N. & Sagata, N. Two structural variants of Nek2 kinase, termed Nek2A and Nek2B, are differentially expressed in Xenopus tissues and development. Dev. Biol. 208, 456–464 (1999)
Acknowledgements
We thank S. Mochida and T. Hunt for sharing their unpublished findings with us and all the laboratory members for discussions. We thank M. J. Lohka for critical reading of the manuscript. This work was supported by grants from the Ministry of Education, Culture, Sports, Science and Technology of Japan to K.O. and T.K.
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Competing interests
Reprints and permissions information is available at www.nature.com/reprints. The authors declare no competing financial interests.
Supplementary information
Supplementary Figures
This file contains Supplementary Figures 1-4 with Legends (PDF 493 kb)
Rights and permissions
About this article
Cite this article
Nishiyama, T., Yoshizaki, N., Kishimoto, T. et al. Transient activation of calcineurin is essential to initiate embryonic development in Xenopus laevis. Nature 449, 341–345 (2007). https://doi.org/10.1038/nature06136
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1038/nature06136
Comments
By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.