BOR - Papers in Press, published online ahead of print
May 19, 2004.
Biol Reprod 2004, 10.1095/biolreprod.104.028647
BIOLOGY OF REPRODUCTION 71, 959965 (2004)
DOI: 10.1095/biolreprod.104.028647
© 2004 by the Society for the Study of Reproduction, Inc.
Selective Passage Through the Uterotubal Junction of Sperm from a Mixed Population Produced by Chimeras of Calmegin-Knockout and Wild-Type Male Mice1
Tomoko Nakanishi3,5,
Ayako Isotani3,4,
Ryo Yamaguchi3,4,
Masahito Ikawa3,
Tadashi Baba5,
Susan S. Suarez6, and
Masaru Okabe2,3
Genome Information Research Center,3
Faculty of Pharmaceutical Sciences,4 Osaka University, Osaka 565-0871, Japan
Institute of Applied Biochemistry,5 University of Tsukuba, Tsukuba Science City, Ibaraki 305-8572, Japan
Department of Biomedical Sciences,6 Cornell University, Ithaca, New York 14853
Loss of calmegin, a testis-specific putative chaperone protein of the endoplasmic reticulum, leads to male sterility because the sperm show defects in migration into the oviduct and do not bind to the zona pellucida. To clarify the mechanism of defective migration, XY
XY chimeras were produced by aggregating wild-type embryos with embryos of transgenic mice lacking functional calmegin genes and expressing enhanced green fluorescent protein (EGFP) in their acrosomes. Chimeric ejaculates contained wild-type, nonfluorescent sperm as well as sperm with EGFP-tagged acrosomes and the defective calmegin gene. Transgenic, wild-type, and chimeric males were mated to wild-type females; however, only wild-type sperm were ever found within the oviducts. Calmegin-knockout sperm, even when they were combined in chimeric ejaculates with wild-type sperm, remained outside of the uterotubal junction. These findings indicate that the presence of wild-type sperm cannot compensate for the inability of calmegin-knockout sperm to enter the oviduct and that successful ascent into the oviduct depends on the capabilities of individual sperm.
1 This work was supported by grants from the Ministry of Education, Culture, Sports, Science, and Technology of Japan (11234203 and 21st Century COE program). S.S.S. and M.O. are equally contributing senior authors.
2 Correspondence. FAX: 81 6 6879 8376; okabe{at}gen-info.osaka-u.ac.jp
Copyright © 2004 by the Society for the Study of Reproduction.