Sperm Plasma Membrane Breakdown During Drosophila Fertilization Requires Sneaky, an Acrosomal Membrane Protein.
From: Department of Biology, University of Washington, Seattle, Washington 98195, USA.
Development (Cambridge, England)
- Publish Date: Dec 2006
- ISSN: 0950-1991
- Volume: 133
- Issue: 24
- Pages: 4871-9
- Medium: Print
- Language: English
- Citation (JAMA): Wilson Kathleen L, Fitch Karen R, Bafus Blaine T, et al. Sperm Plasma Membrane Breakdown During Drosophila Fertilization Requires Sneaky, an Acrosomal Membrane Protein.. Development Dec 2006;133:4871-9
Abstract
Fertilization typically involves membrane fusion between sperm and eggs. In Drosophila, however, sperm enter eggs with membranes intact. Consequently, sperm plasma membrane breakdown (PMBD) and subsequent events of sperm activation occur in the egg cytoplasm. We previously proposed that mutations in the sneaky (snky) gene result in male sterility due to failure in PMBD. Here we support this proposal by demonstrating persistence of a plasma membrane protein around the head of snky sperm after entry into the egg. We further show that snky is expressed in testes and encodes a predicted integral membrane protein with multiple transmembrane domains, a DC-STAMP-like domain, and a variant RING finger. Using a transgene that expresses an active Snky-Green fluorescent protein fusion (Snky-GFP), we show that the protein is localized to the acrosome, a membrane-bound vesicle located at the apical tip of sperm. Snky-GFP also allowed us to follow the fate of the protein and the acrosome during fertilization. In many animals, the acrosome is a secretory vesicle with exocytosis essential for sperm penetration through the egg coats. Surprisingly, we find that the Drosophila acrosome is a paternally inherited structure. We provide evidence that the acrosome induces changes in sperm plasma membrane, exclusive of exocytosis and through the action of the acrosomal membrane protein Snky. Existence of testis-expressed Snky-like genes in many animals, including humans, suggests conserved protein function. We relate the characteristics of Drosophila Snky, acrosome function and sperm PMBD to membrane fusion events that occur in other systems.
Mesh Headings (Keywords): Acrosome, Amino Acid Sequence, Animals, Cell Membrane, Drosophila, Drosophila Proteins, Female, Fertility, Fertilization, Green Fluorescent Proteins, Male, Membrane Proteins, Molecular Sequence Data, Ovum, Protein Structure, Tertiary, Rats, Sequence Alignment, Sperm Capacitation, Testis
Check for Full Text / PubMed Unique Identifier (PMID): 17092953
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