The mammalian acrosome reaction (AR) is a sperm head exocytotic event essential to fertilization. A neuronal glycine receptor/Cl channel (GlyR) is present in mammalian sperm and is necessary for the AR initiated by the egg zona pellucida (ZP) protein ZP3. The overall goal of this grant is to increase our understanding of the role of the GlyR in the ZP-initiated AR and the mechanisms involved in controlling its activation. We hypothesize that ZP activates the GlyR directly or via receptor cross-talk, that Cl- efflux through the GlyR is at least partly responsible for depolarization leading to Ca 2+ influx essential to the AR and that activation of the GlyR involves PKA-mediated phosphorylation. The effects of mouse ZP and human recombinant human ZP3 (rhZP3) on mouse sperm and human sperm respectively will be studied using imaging, photometry and antagonists in in vitro AR assays. The following are the Specific Aims. 1. Determination of whether the human and mouse sperm GlyR mediate the intracellular Ca 2+ (Ca2+i) increase elicited by rhZP3, mouse ZP or glycine during the AR. 2. Determination of whether the human and mouse sperm GlyR are involved in the membrane potential change elicited by glycine, rhZP3 or mouse ZP. 3. Determination of whether phosphorylation of the GlyR by protein kinase A (PKA) is involved in AR initiated by glycine, mouse ZP or rhZP3. 4. Determination of whether PKA is important to GlyR mediation of membrane potential change and to the Ca2+i increase elicited by glycine, mouse ZP and rhZP3. 5. Determination of whether mouse ZP-mediated membrane potential and Ca2+i changes would be absent or decreased in sperm from mice with GlyR mutations. 6. Determination of whether the AR of sperm from mice with GlyR mutations occur on the ZP of intact mouse eggs in vitro. If not, determination of whether the AR and fertilization be stimulated by progesterone in these sperm while they are on the ZP? Being able to compare results obtained with human sperm and rhZP3 and those obtained with mouse sperm and mouse ZP synthesized in vivo will help us determine whether common mechanisms are involved in mammalian species.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
2R01HD033368-05A1
Application #
6571377
Study Section
Reproductive Biology Study Section (REB)
Program Officer
Rankin, Tracy L
Project Start
1997-03-01
Project End
2007-02-28
Budget Start
2003-04-01
Budget End
2004-02-29
Support Year
5
Fiscal Year
2003
Total Cost
$267,300
Indirect Cost
Name
University of California Davis
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
047120084
City
Davis
State
CA
Country
United States
Zip Code
95618
Kumar, Priyadarsini; Meizel, Stanley (2008) Identification and spatial distribution of glycine receptor subunits in human sperm. Reproduction 136:387-90
Kumar, Priyadarsini; Ferns, Michael J; Meizel, Stanley (2006) Identification of agrinSN isoform and muscle-specific receptor tyrosine kinase (MuSK) [corrected] in sperm. Biochem Biophys Res Commun 342:522-8
Bray, Christopher; Son, Jung-Ho; Kumar, Priyadarsini et al. (2005) Mice deficient in CHRNA7, a subunit of the nicotinic acetylcholine receptor, produce sperm with impaired motility. Biol Reprod 73:807-14
Meizel, Stanley; Son, Jung-Ho (2005) Studies of sperm from mutant mice suggesting that two neurotransmitter receptors are important to the zona pellucida-initiated acrosome reaction. Mol Reprod Dev 72:250-8
Kumar, Priyadarsini; Meizel, Stanley (2005) Nicotinic acetylcholine receptor subunits and associated proteins in human sperm. J Biol Chem 280:25928-35
Bray, C; Son, J-H; Meizel, S (2005) Acetylcholine causes an increase of intracellular calcium in human sperm. Mol Hum Reprod 11:881-9
Meizel, Stanley (2004) The sperm, a neuron with a tail: 'neuronal' receptors in mammalian sperm. Biol Rev Camb Philos Soc 79:713-32
Son, Jung-Ho; Meizel, Stanley (2003) Evidence suggesting that the mouse sperm acrosome reaction initiated by the zona pellucida involves an alpha7 nicotinic acetylcholine receptor. Biol Reprod 68:1348-53
Bray, Christopher; Son, Jung-Ho; Meizel, Stanley (2002) A nicotinic acetylcholine receptor is involved in the arosome reaction of human sperm initiated by recombinant human ZP3. Biol Reprod 67:782-8
Bray, Christopher; Son, Jung-Ho; Kumar, Priyadarsini et al. (2002) A role for the human sperm glycine receptor/Cl(-) channel in the acrosome reaction initiated by recombinant ZP3. Biol Reprod 66:91-7

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