Dynamic Development

Main Page Dynamic Development

The Foundations of Developmental Biology


From Sperm and Egg to Embryo

Genetic Regulation of Development

Organizing the Multicellular Embryo

Generating Cell Diversity

Dynamic Development at a Glance

Learning Resources

Research Resources

The Developmental Biology Journal Club

Developmental Biology Tutorial

Fertilization: Activation of Development

How does the egg respond to fertilization?

Because it has medical, sociological, agricultural and economic implications, fertilization is one of the most fascinating and intensely-studied aspects of development. You should study carefully the textbook and the links listed below to understand fertilization. Be aware of distinct mechanisms that are used by different organisms.

The activation of development is a consequence of a sequence of events triggered by the sperm at the egg surface. The events and mechanism of egg activation in the frog egg are reviewed in the next series of links. Advance through these links until you come to "Frogs in Space".

Now, let's examine two additional aspects of this topic:

"Decondensation of sperm chromatin" from Zygote

"Structural changes in the endoplasmic reticulum during fertilization" from Zygote

Learning Objectives

  • Reconstruct the sequence of ionic events that initiate development after sperm-egg contact.
  • How is the gray crescent formed in the fertilized amphibian egg?
  • Describe subcortical rotation of the fertilized frog egg.
  • Describe the changes that occur in the deep cytoplasm of the fertilized frog egg.

Digging Deeper:

Link to Related Material

The Calcium Tsunami thru Fertilizing Medaka Fish Egg

Recent Literature

Carroll, D.J., Ramarao, C.S., Melmann, L.M., Roche, S., Terasaki, M., and Jaffe, L.A. 1997. Calcium release at fertilization in starfish eggs is mediated by phospholipase C gamma. J. Cell Biol. 138:1303-11.

Digonnet, C., Aldon, D., Leduc, N., Dumas, C. and Rougier, M. 1997. First evidence of a calcium transient in flowering plants at fertilization. Development 124: 2867-2874.

Gallicano, G.I., McGaughey, R.W. and Capco, D.G. 1997. Activation of protein kinase C after fertilization is required for remodeling the mouse egg into the zygote. Mol. Reprod. Dev. 46: 587-601.

Glahn, D., Mark, S.D., Behr, R.K., Nuccitelli, R. 1999. Tyrosine kinase inhibitors block sperm-induced egg activation in Xenopus Laevis. Dev. Biol. 205:171-180.

Meizel, S., Turner, K.O. and Nuccitelli, R. 1997. Progesterone triggers a wave of increased free calcium during the human sperm acrosome reaction. Develop. Biol. 182: 67-75.

Sato, K., Iwao, Y., Fujimura, T., Tamaki, I., Ogawa, K., Iwasaki, T., Tokmakov, A.A., Hatano, O., and Fukami, Y. 1999. Evidence for the involvement of a Src-related tyrosine kinase in Xenopus egg activation. Dev. Biol. 209:308-320.

Sette, C., Bevilacqua, A., Bianchini, A., Mangia, F., Geremia, R. amd Rossi, P. 1997. Parthenogenetic activation of mouse eggs by microinjection of a truncated c-kit tyrosine kinase present in spermatozoa. Development 124: 2267-2274.

Stith, B.J., Woronoff, K., Espinoza, R. and Smart, T. 1997. sn-1,2-diacylglycerol and choline increase after fertilization in Xenopus laevis. Mol. Biol. Cell 8: 755-765.

Swann, K. and A.A. Lai. 1997. A novel signalling mechanism for generating Ca2+ oscillations at fertilization in mammals. BioEssays 19: 371-378.


Browder, L.W., Erickson, C.A. and Jeffery, W.R. 1991. Developmental Biology. Third edition. Saunders College Pub. Philadelphia.

Gilbert, S.F. 1997. Developmental Biology. Fifth edition. Sinauer Associates, Inc. Publishers, Sunderland, Massachusetts.

Dynamic Development at a Glance
Main Page Dynamic Development

Dynamic Development is a Virtual Embryo learning resource

This material may be reproduced for educational purposes only provided credit is given to the original source.
Leon Browder & Laurie Iten (Ed.) Dynamic Development
Last revised Monday, August 4, 1998