Hostname: page-component-cd9895bd7-dzt6s Total loading time: 0 Render date: 2024-12-24T13:15:03.115Z Has data issue: false hasContentIssue false
  • English
  • Français

Cytochalasin B does not block sperm penetration into denuded starfish oocytes

Published online by Cambridge University Press:  26 September 2008

Keiichiro Kyozuka  and
Kenzi Osanai
Keiichiro Kyozuka*
Affiliation:
Asamushi Marine Biological Station, Tohoku University, Asamushi, Aomori 039-34, JAPAN.
Kenzi Osanai
Affiliation:
Asamushi Marine Biological Station, Tohoku University, Asamushi, Aomori 039-34, JAPAN.
*
Keiichiro Kyozuka, PhD, Asamushi Marine Biological Station, Tohoku University, Asamushi, Aomori 039-34, Japan. Telephone: 81-177-52-3388. Fax: 81-177-52-3031
Get access Rights & Permissions [Opens in a new window]

Summary

During fertilisation in starfish oocytes, the fertilisation cone develops temporarily beneath the penetrating sperm. The role of the fertilisation cone in sperm incorporation in the starfish Asterias amurensis was examined using cytochalasin B (CB). CB (2 μM) allowed sperm acrosomal process–egg plasma membrane fusion and egg activation, but inhibited the development of the fertilisation cone containing actin microfilaments. When sperm were added to intact oocytes (with the jelly coat and vitelline coat) in seawater containing CB, the sperm head did not penetrate the fertilisation membrane. Although the acrosomal process fused with egg plasma membrane, the sperm head remained outside the fertilisation membrane. On the other hand, denuded oocytes without the jelly coat and vitelline coat allowed sperm penetration even in the presence of 2 μM CB. Electron microscopy revealed that sperm organelles, including the acrosomal process, nucleus, mitochondrion and tail, were incorporated into the slightly electron-dense cytoplasm, which was similar to the cytoplasm of the fertilisation cone. These results show that the development of the fertilisation cone/actin filament complex is not essential for incorporation of the sperm, since incorporation can occur in denuded oocytes. However, the cone is required for fertilisation of intact oocytes, suggesting that this actin-filament-containing structure is necessary for getting the sperm through the outer egg coats.

Keywords

Asteria amurensisEgg coatFertilisationFertilisation coneMicrofilament
Type
Article
Information
Zygote , Volume 2 , Issue 2 , May 1994 , pp. 103 - 109
Copyright
Copyright © Cambridge University Press 1994

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Byrd, W. & Perry, G. (1980) Cytochalasin B blocks sperm incorporation but allows activation of the sea urchin egg. Exp. Cell Res. 126, 333–42.CrossRefGoogle ScholarPubMed
Chambers, E.L. & McCulloh, D.H. (1990). Excitation activation and sperm entry in voltage-clamped sea urchin eggs. J. Reprod. Fert. 42(Suppl.), 117–32.Google ScholarPubMed
Gould-Somero, M., Holland, L. & Paul, M. (1977). Cytochalasin B inhibits sperm penetration into eggs of Urechis caupo (Echiura). Dev. Biol. 52, 11–22.CrossRefGoogle Scholar
Hoshi, M. (1985). Lysins. In: Biology of Fertilisation, vol. 2, Biology of Sperm, ed. Metz, C.B. & Monroy, A., pp. 431–62. New York: Academic press.CrossRefGoogle Scholar
Jessen, H., Behnke, O., Wingstrand, K.G. & Rostgaard, J. (1973). Actin-like filaments in the acrosomal apparatus of spermatozoa sea urchin. Exp. Cell Res. 80, 47–54.CrossRefGoogle ScholarPubMed
Kyozuka, K. (1993). The mechanism of sperm penetration in starfish. Bull. Mar. Biol. Stn. Asamushi, Tohoku Univ. 19, 1–17.Google Scholar
Kyozuka, K. & Osanai, K. (1984). Denuded starfish oocytes can be fertilized with acrosome-reacted sperm. Bull. Mar. Biol. Stn. Asamushi, Tohoku Univ. 17, 213–16.Google Scholar
Kyozuka, K. & Osanai, K. (1988a). Fertilisation cone formation in starfish oocytes: the role of the egg cortex actin microfilaments in sperm incorporation. Gamete Res. 20, 275–85.CrossRefGoogle ScholarPubMed
Kyozuka, K. & Osanai, K. (1988b). Phagocytosis of sperm heads lacking the acrosomal process by unfertilized starfish oocytes. Gamete Res. 21, 127–34.CrossRefGoogle ScholarPubMed
Longo, F.J. (1978). Effects of cytochalasin B on sperm-egg interactions. Dev. Biol. 67, 249–65.CrossRefGoogle ScholarPubMed
Longo, F.J. (1980). Organization of microfilaments in sea urchin (Arbacia puncturata) eggs at fertilisation: effect of cytochalasin B Dev. Biol. 74, 422–33.CrossRefGoogle ScholarPubMed
Nemoto, S., Yoneda, M., & Uemura, I. (1980). Marked decrease in the rigidity of starfish oocytes induced by 1–methyladenine. Dev. Growth Differ. 22, 315–25.CrossRefGoogle Scholar
Sanger, J.W. & Sanger, J.M. (1975). Polymerization of sperm actin in the presence of cytochalasin B. J. Exp. Zool. 193, 441–7.CrossRefGoogle ScholarPubMed
Sawada, T. & Osanai, K. (1981). The cortical contraction related to the ooplasmic segregation in Ciona intestinalis. Wilhelm Rouxs Arch. Dev. Biol. 190, 208–14.CrossRefGoogle Scholar
Schatten, H. & Schatten, G. (1980). Surface activity at the egg plasma membrane during sperm incorporation and its cytochalasin B sensitivity. Dev. Biol. 78, 435–49.CrossRefGoogle ScholarPubMed
Schroeder, T.E. & Christen, R. (1982). Polymerization of actin without acrosomal exocytosis in starfish sperm: visualization with NBD-phallacidin. Exp. Cell Res. 140, 363–71.CrossRefGoogle ScholarPubMed
Speksnijder, J.E.Jaffe, L.F. & Sardet, C. (1989). Polarity of sperm entry in the ascidian egg. Dev. Biol. 133, 180–4.CrossRefGoogle ScholarPubMed
Tilney, L.G. (1985). The acrosome reaction. In: Biology of Fertilisation, vol. 2, Biology of Sperm, ed. Metz, C.B. & Monoroy, A., pp. 157–213. New York: Academic Press.CrossRefGoogle Scholar
Tilney, L.G.& Jaffe, L.A. (1980). Actin, microvilli, and the fertilisation cone of sea urchin eggs. J. Cell Biol. 87, 771–82.CrossRefGoogle ScholarPubMed
Vacquier, V.D. (1981). Dynamic changes of the egg cortex. Dev. Biol. 84, 1–26.CrossRefGoogle ScholarPubMed