HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Manandhar, G. Articles by Toshimori, K. Search for Related Content PubMed PubMed Citation Articles by Manandhar, G. Articles by Toshimori, K. Agricola Articles by Manandhar, G. Articles by Toshimori, K.

Exposure of Sperm Head Equatorin after Acrosome Reaction and Its Fate after Fertilization in Mice¹

^a Department of Anatomy and Reproductive Cell Biology, Miyazaki Medical College, Miyazaki 8891692, Japan

ABSTRACT

Equatorin is a sperm head equatorial protein, possibly involved in sperm-oocyte fusion (Toshimori et al., Biol Reprod 1998; 59:22–29). In the present work, we have shown that equatorin contained in the posterior acrosome is detectable only after spontaneous or induced acrosome reactions following fixation and permeabilization, but not in intact spermatozoa. The presence of protease inhibitors during sonication or ionophore treatments does not inhibit the exposure of the antigenic epitope. The zona-penetrated spermatozoa lying in the perivitelline space display equatorin, similar to those of the acrosome-reacted ones. After sperm-egg fusion during in vitro fertilization (IVF), the equatorin dissociates from the sperm head equatorial region and remains at the vicinity of the decondensing male pronuclei. During pronuclear apposition stage, it is pushed away from the pronuclei, possibly by the perinuclear microtubules. After first cleavage, equatorin is inherited by one of the proembryonic cells. The residual equatorin disappears after the second cleavage. Microinjected whole spermatozoa or sperm heads into the MII stage oocytes display equatorin similar to those of the perivitelline sperm. After activation, it dissociates from the sperm nuclei in a similar manner as during IVF. The mode of equatorin degeneration during fertilization is similar to those of the sperm tail components or mitochondria, but different from those of the membrane associated proteins.

FOOTNOTES

First decision: 30 April 2001.

¹ K.T. is a recipient of a Grant-in-Aid for Scientific Research (12670022) from the Ministry of Education, Science, Sports and Culture of Japan.

² Correspondence: K. Toshimori, Department of Anatomy and Reproductive Cell Biology, Miyazaki Medical College, Kihara 5200, Miyazaki 8891692, Japan. FAX: 81 985 85 1363; ktoshi{at}post.miyazaki-med.ac.jp

This article has been cited by other articles:

				M. J. Wolkowicz, J. Shetty, A. Westbrook, K. Klotz, F. Jayes, A. Mandal, C. J. Flickinger, and J. C. Herr Equatorial Segment Protein Defines a Discrete Acrosomal Subcompartment Persisting Throughout Acrosomal Biogenesis Biol Reprod, September 1, 2003; 69(3): 735 - 745. [Abstract] [Full Text] [PDF]

				G. Manandhar and K. Toshimori Fate of Postacrosomal Perinuclear Theca Recognized by Monoclonal Antibody MN13 after Sperm Head Microinjection and Its Role in Oocyte Activation in Mice Biol Reprod, February 1, 2003; 68(2): 655 - 663. [Abstract] [Full Text] [PDF]

				T.J. Davies and R.L. Gardner The plane of first cleavage is not related to the distribution of sperm components in the mouse Hum. Reprod., September 1, 2002; 17(9): 2368 - 2379. [Abstract] [Full Text] [PDF]