title: Evidence for participation of GCS1 in fertilization of the starlet sea anemone Nematostella vectensis: implication of a common mechanism of sperm-egg fusion in plants and animals.
abstract: It has been reported that GCS1 (Generative Cell Specific 1) is a transmembrane protein that is exclusively expressed in sperm cells and is essential for gamete fusion in flowering plants. The GCS1 gene is present not only in angiosperms but also in unicellular organisms and animals, implying the occurrence of a common or ancestral mechanism of GCS1-mediated gamete fusion. In order to elucidate the common mechanism, we investigated the role of GCS1 in animal fertilization using a sea anemone (Cnidaria), Nematostella vectensis. Although the existence of the GCS1 gene in N. vectensis has been reported, the expression of GCS1 in sperm and the role of GCS1 in fertilization are not known. In this study, we showed that the GCS1 gene is expressed in the testis and that GCS1 protein exists in sperm by in situ hybridization and proteomic analysis, respectively. Then we made four peptide antibodies against the N-terminal extracellular region of NvGCS1. These antibodies specifically reacted to NvGCS1 among sperm proteins on the basis of Western analysis and potently inhibited fertilization in a concentration-dependent manner. These results indicate that sperm GCS1 plays a pivotal role in fertilization, most probably in sperm-egg fusion, in a starlet sea anemone, suggesting a common gamete-fusion mechanism shared by eukaryotic organisms.
authors.affiliation: Sugashima Marine Biological Laboratory, Graduate School of Science, Nagoya University, Sugashima, Toba 517-0004, Japan.
authors.forename: Eerdundagula
authors.initials: E
authors.lastname: Ebchuqin
authors.affiliation: Sugashima Marine Biological Laboratory, Graduate School of Science, Nagoya University, Sugashima, Toba 517-0004, Japan.
authors.forename: Naoto
authors.initials: N
authors.lastname: Yokota
authors.affiliation: Sugashima Marine Biological Laboratory, Graduate School of Science, Nagoya University, Sugashima, Toba 517-0004, Japan.
authors.forename: Lixy
authors.initials: L
authors.lastname: Yamada
authors.affiliation: Marine Genomics Unit, Okinawa Institute of Science and Technology, Onna, Okinawa 904-0495, Japan.
authors.forename: Yuuri
authors.initials: Y
authors.lastname: Yasuoka
authors.affiliation: Laboratory of Molecular Genetics, Graduate School of Science, Nagoya University, Chikusa-ku, Furo-cho, Nagoya 464-8602, Japan.
authors.forename: Mari
authors.initials: M
authors.lastname: Akasaka
authors.affiliation: Department of Biology, Miyagi University of Education, Sendai, Miyagi 980-0845, Japan.
authors.forename: Mio
authors.initials: M
authors.lastname: Arakawa
authors.affiliation: Department of Biology, Miyagi University of Education, Sendai, Miyagi 980-0845, Japan.
authors.forename: Ryusaku
authors.initials: R
authors.lastname: Deguchi
authors.affiliation: Waseda Institute for Advanced Study, Waseda University, Shinjuku, Tokyo 169-8050, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Mori
authors.affiliation: Sugashima Marine Biological Laboratory, Graduate School of Science, Nagoya University, Sugashima, Toba 517-0004, Japan. Electronic address: hsawada@bio.nagoya-u.ac.jp.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Sawada
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D005306:Fertilization / Q000502:physiology*; D007447:Invertebrate Hormones / Q000502:physiology*; D008297:Male; D008565:Membrane Proteins / Q000502:physiology*; D010944:Plants / Q000235:genetics; D012615:Sea Anemones; D016415:Sequence Alignment; D013084:Sperm-Ovum Interactions / Q000187:drug effects*; D013094:Spermatozoa / Q000378:metabolism
chemical_list: D007447:Invertebrate Hormones; D008565:Membrane Proteins
keywords: Cnidaria; Egg; Fertilization; Membrane fusion; Sperm