The long term objective of this study is to contribute to the better understanding of the basic mechanisms involved in mammalian fertilization and consequently to the better control of human fertility. In this study, major emphasis will be placed on analyzing the processes and mechanisms of sperm-egg fusion and associated phenomena. Hamsters, mice and guinea pigs will be used as model animals. Specific questions we intend to answer include: 1. When does the egg plasma membrane gain and lose the ability to fuse with spermatozoa? 2. What sort of chemical changes make acrosome-reacted spermatozoa fusible? 3. What sort of membrane molecules are involved in sperm-egg fusion? 4. Can acrosome-reacted spermatozoa fuse with any type of (artificial) membranes? 5. What sort of agents or conditions prevent or promote sperm-egg fusion? 6. Is it possible to render living spermatozoa permanently incapable of fusing with eggs? 7. Is it possible to fuse isolated sperm nuclei with eggs? 8. Are calpain and intracellular calcium ions involved in the decondensation of the sperm nucleus in the cytoplasm of a fertilized egg? 9. How stable are isolated sperm nuclei in vitro? 10. Can an isolated sperm nucleus participate in the development of an embryo after being injected into an egg?

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
5R01HD003402-25
Application #
3310202
Study Section
Reproductive Biology Study Section (REB)
Project Start
1977-09-30
Project End
1993-06-30
Budget Start
1992-04-01
Budget End
1993-06-30
Support Year
25
Fiscal Year
1992
Total Cost
Indirect Cost
Name
University of Hawaii
Department
Type
Schools of Medicine
DUNS #
121911077
City
Honolulu
State
HI
Country
United States
Zip Code
96822
Yanagimachi, Ryuzo (2005) Intracytoplasmic injection of spermatozoa and spermatogenic cells: its biology and applications in humans and animals. Reprod Biomed Online 10:247-88
Yanagimachi, Ryuzo; Wakayama, Teruhiko; Kishikawa, Hidefumi et al. (2004) Production of fertile offspring from genetically infertile male mice. Proc Natl Acad Sci U S A 101:1691-5
Kishikawa, H; Tateno, H; Yanagimachi, R (1999) Fertility of mouse spermatozoa retrieved from cadavers and maintained at 4 degrees C. J Reprod Fertil 116:217-22
Perry, A C; Wakayama, T; Yanagimachi, R (1999) A novel trans-complementation assay suggests full mammalian oocyte activation is coordinately initiated by multiple, submembrane sperm components. Biol Reprod 60:747-55
Cummins, J M; Kishikawa, H; Mehmet, D et al. (1999) Fate of genetically marked mitochondrial DNA from spermatocytes microinjected into mouse zygotes. Zygote 7:151-6
Wakayama, T; Yanagimachi, R (1998) Development of normal mice from oocytes injected with freeze-dried spermatozoa. Nat Biotechnol 16:639-41
Cummins, J M; Wakayama, T; Yanagimachi, R (1998) Fate of microinjected spermatid mitochondria in the mouse oocyte and embryo. Zygote 6:213-22
Dozortsev, D; Wakaiama, T; Ermilov, A et al. (1998) Intracytoplasmic sperm injection in the rat. Zygote 6:143-7
Maeda, Y; Yanagimachi, H; Tateno, H et al. (1998) Decondensation of the mouse sperm nucleus within the interphase nucleus. Zygote 6:39-45
Wakayama, T; Yanagimachi, R (1998) Fertilisability and developmental ability of mouse oocytes with reduced amounts of cytoplasm. Zygote 6:341-6

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