Fertilization depends on the successful interaction of the sperm with the egg. The interactions between the gamete membranes is a fascinating process from a cell biological standpoint, beginning with the sperm contacting and attaching to the egg membrane, progressing to firm cell-cell adhesion, and culminating in membrane fusion. Our understanding of the molecular mechanisms underlying gamete membrane interactions is still very incomplete. The overall, long term goal of this project is to understand the mechanism and regulation of cell adhesion between mammalian gametes. Two sperm proteins that participate in mammalian gamete membrane interactions are members the ADAM (A Disintegrin and A Metalloprotease) family of proteins, fertilin alpha (ADAM1) and fertilin beta (ADAM2). Our determination of the key amino acids in fertilin beta that interact with the egg plasma membrane has led to the identification of potential fertilin beta binding partners on eggs.
Specific Aim 1 of this proposal will build on this work with investigation of the interactions of candidate integrins with fertilin beta, including studies of eggs deficient in the beta1 integrin subunit. Our studies of fertilin a indicate that this sperm protein can use two different domains to interact with the egg membrane. Following up on this, Specific Aim 2 will determine how these domains of fertilin alpha interact with the egg membrane, including structure-function analysis and identification of binding partners. In addition to this analysis of specific molecular interactions, this project also will examine the mechanism by which sperm-egg adhesion occurs via the coordinated function of these and other gamete molecules. It has become clear that the interaction between the gametes is a complex event, likely to be mediated by multiple molecules on the sperm and egg and to occur in a step-wise fashion. We propose a model for gamete cell adhesion, based on other cell adhesion systems, in which multiple molecules participate and the interactions of gamete adhesion molecules progress to form firm adhesions between the sperm and egg.
Specific Aim 3 will test aspects of this model, including studies of the roles of the egg cytoskeleton and the egg membrane protein CD9 in the strengthening of adhesions to sperm ADAMs. Results of these studies will have applications to human reproductive health, with implications for the management of infertility and fertility. This research also will also address fundamental questions in cell adhesion biology by examining this interesting, biologically relevant cell-cell interaction event.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
5R01HD037696-07
Application #
6844358
Study Section
Reproductive Biology Study Section (REB)
Program Officer
Rankin, Tracy L
Project Start
1998-09-07
Project End
2009-01-31
Budget Start
2005-02-01
Budget End
2006-01-31
Support Year
7
Fiscal Year
2005
Total Cost
$367,875
Indirect Cost
Name
Johns Hopkins University
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
001910777
City
Baltimore
State
MD
Country
United States
Zip Code
21218
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Evans, Janice P; Robinson, Douglas N (2011) The spatial and mechanical challenges of female meiosis. Mol Reprod Dev 78:769-77
Marcello, Matthew R; Jia, Weitao; Leary, Julie A et al. (2011) Lack of tyrosylprotein sulfotransferase-2 activity results in altered sperm-egg interactions and loss of ADAM3 and ADAM6 in epididymal sperm. J Biol Chem 286:13060-70
Marcello, Matthew R; Evans, Janice P (2010) Multivariate analysis of male reproductive function in Inpp5b-/- mice reveals heterogeneity in defects in fertility, sperm-egg membrane interaction and proteolytic cleavage of sperm ADAMs. Mol Hum Reprod 16:492-505
Desiderio, Ulyana V; Zhu, Xiaoling; Evans, Janice P (2010) ADAM2 interactions with mouse eggs and cell lines expressing ?4/?9 (ITGA4/ITGA9) integrins: implications for integrin-based adhesion and fertilization. PLoS One 5:e13744
Larson, Stephanie M; Lee, Hyo J; Hung, Pei-hsuan et al. (2010) Cortical mechanics and meiosis II completion in mammalian oocytes are mediated by myosin-II and Ezrin-Radixin-Moesin (ERM) proteins. Mol Biol Cell 21:3182-92
Glazar, Amanda I; Evans, Janice P (2009) Immunoglobulin superfamily member IgSF8 (EWI-2) and CD9 in fertilisation: evidence of distinct functions for CD9 and a CD9-associated protein in mammalian sperm-egg interaction. Reprod Fertil Dev 21:293-303
Evans, Janice P (2009) Egg integrins: back in the game of mammalian fertilization. ACS Chem Biol 4:321-3
Vjugina, Ulyana; Zhu, Xiaoling; Oh, Eugene et al. (2009) Reduction of mouse egg surface integrin alpha9 subunit (ITGA9) reduces the egg's ability to support sperm-egg binding and fusion. Biol Reprod 80:833-41
Dalo, Diane T; McCaffery, J Michael; Evans, Janice P (2008) Ultrastructural analysis of egg membrane abnormalities in post-ovulatory aged eggs. Int J Dev Biol 52:535-44