Human Sperm Binding to Transgenic Mouse Eggs

At fertilization, the binding of sperm to the zona pellucida induces the acrosome reaction
releasing lytic enzymes that facilitate the passage of the sperm through the zona. The sperm
then fuses with the egg s plasma membrane and enters the egg s cytoplasm. The zona pellucida,
an extracellular matrix composed of three or four glycoproteins, mediates the
species-specific binding of sperm to egg. Although homologous proteins are present in mouse
and humans, human sperm will not bind to the mouse zona pellucida and when the zona pellucida
is experimentally removed, human sperm will not bind or fuse to the mouse egg's plasma
membrane. We have established transgenic mouse lines that express one or more human or rat
zona proteins. We wish to determine if human sperm will bind to these chimeric zonae and if
this binding will induce the human sperm acrosome reaction. Sperm and devitalized eggs will
be collected by collaborating institution(s) under protocols and consent forms approved by
that institution's IRB. Alternatively, anonymous fertile human sperm will be obtained from a
commercial sperm bank using a donor consent agreement. Only procedures already being
performed on subjects for diagnostic or treatment purposes will be used.

- INCLUSION CRITERIA:

Without regard to ethnic/race background, all subjects will be men and women over the age
of 18 who are neither mentally retarded nor disabled.