Proteomic analysis of sperm regions that mediate sperm-egg interactions

Authors

  • Kathryn K. Stein,

    1. Section of Molecular and Cellular Biology, University of California, Davis, Davis, CA, USA
    2. Current address: Laboratory of Biochemistry and Genetics, NIDDK, National Institutes of Health, Bethesda, MD, USA
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  • Jowell C. Go,

    1. Section of Molecular and Cellular Biology, University of California, Davis, Davis, CA, USA
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  • William S. Lane,

    1. Microchemistry and Proteomics Analysis Facility, Harvard University, Cambridge, MA, USA
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  • Paul Primakoff,

    1. Department of Cell Biology and Human Anatomy, School of Medicine, University of California, Davis, Davis, CA, USA
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  • Diana G. Myles Dr.

    Corresponding author
    1. Section of Molecular and Cellular Biology, University of California, Davis, Davis, CA, USA
    • Section of Molecular and Cellular Biology, 1 Shields Ave., University of California, Davis, Davis, CA 95616, USA Fax: +1-301-405-0240
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Abstract

The sperm interacts with three oocyte-associated structures during fertilization: the cumulus cell layer surrounding the oocyte, the egg extracellular matrix (the zona pellucida), and the oocyte plasma membrane. Each of these interactions is mediated by the sperm head, probably through proteins both on the sperm surface and within the acrosome, a specialized secretory granule. In this study, we have used subcellular fractionation in order to generate a proteome of the sperm head subcellular compartments that interact with oocytes. Of the proteins we identified for which a gene knockout has been tested, a third have been shown to be essential for efficient reproduction in vivo. Many of the other presently untested proteins are likely to have a similarly important role. Twenty-five percent of the cell surface fraction proteins are previously uncharacterized. We have shown that at least two of these novel proteins are localized to the sperm head. In summary, we have identified over 100 proteins that are expressed on mature sperm at the site of sperm-oocyte interactions.

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