title: Mouse sperm lacking cell surface hyaluronidase PH-20 can pass through the layer of cumulus cells and fertilize the egg.
abstract: The function of glycosylphosphatidylinositol-anchored sperm hyaluronidase PH-20 in fertilization has long been believed to enable acrosome-intact sperm to pass through the layer of cumulus cells and reach the egg zona pellucida. In this study, we have produced mice carrying a null mutation in the PH-20 gene using homologous recombination. Despite the absence of sperm PH-20, the mutant male mice were still fertile. In vitro fertilization assays showed that mouse sperm lacking PH-20 possess a reduced ability to disperse cumulus cells from the cumulus mass, resulting in delayed fertilization solely at the early stages after insemination. Moreover, SDS-PAGE of sperm extracts and subsequent Western blot analysis revealed the presence of other hyaluronidase(s), except PH-20, presumably within the acrosome of mouse sperm. These data provide evidence that PH-20 is not essential for fertilization, at least in the mouse, suggesting that the other hyaluronidase(s) may play an important role in sperm penetration through the cumulus cell layer and/or the egg zona pellucida, possibly in cooperation with PH-20, although the importance of sperm motility cannot be neglected.
authors.affiliation: Institute of Applied Biochemistry, University of Tsukuba, Tsukuba Science City, Ibaraki 305-8572, Japan.
authors.forename: Daichi
authors.initials: D
authors.lastname: Baba
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Kashiwabara
authors.forename: Arata
authors.initials: A
authors.lastname: Honda
authors.forename: Kazuo
authors.initials: K
authors.lastname: Yamagata
authors.forename: Qing
authors.initials: Q
authors.lastname: Wu
authors.forename: Masahito
authors.initials: M
authors.lastname: Ikawa
authors.forename: Masaru
authors.initials: M
authors.lastname: Okabe
authors.forename: Tadashi
authors.initials: T
authors.lastname: Baba
mesh_terms: D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000201:enzymology; D017931:DNA Primers; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D005306:Fertilization; D006821:Hyaluronoglucosaminidase / Q000235:genetics / Q000378:metabolism*; D008297:Male; D051379:Mice; D008817:Mice, Mutant Strains; D013084:Sperm-Ovum Interactions; D013094:Spermatozoa / Q000201:enzymology / Q000502:physiology*; D015044:Zona Pellucida / Q000378:metabolism
chemical_list: D015815:Cell Adhesion Molecules; D017931:DNA Primers; D006821:Hyaluronoglucosaminidase; C066852:hyaluronidase PH-20