title: Two HAP2-GCS1 homologs responsible for gamete interactions in the cellular slime mold with multiple mating types: Implication for common mechanisms of sexual reproduction shared by plants and protozoa and for male-female differentiation.
abstract: Fertilization is a central event in sexual reproduction, and understanding its molecular mechanisms has both basic and applicative biological importance. Recent studies have uncovered the molecules that mediate this process in a variety of organisms, making it intriguing to consider conservation and evolution of the mechanisms of sexual reproduction across phyla. The social amoeba Dictyostelium discoideum undergoes sexual maturation and forms gametes under dark and humid conditions. It exhibits three mating types, type-I, -II, and -III, for the heterothallic mating system. Based on proteome analyses of the gamete membranes, we detected expression of two homologs of the plant fertilization protein HAP2-GCS1. When their coding genes were disrupted in type-I and type-II strains, sexual potency was completely lost, whereas disruption in the type-III strain did not affect mating behavior, suggesting that the latter acts as female in complex organisms. Our results demonstrate the highly conserved function of HAP2-GCS1 in gamete interactions and suggest the presence of additional allo-recognition mechanisms in D. discoideum gametes.
authors.affiliation: Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan.
authors.forename: Marina
authors.initials: M
authors.lastname: Okamoto
authors.affiliation: Sugashima Marine Biological Laboratory, Graduate School of Science, Nagoya University, 429-63 Sugashima, Toba, Mie 517-0004, Japan.
authors.forename: Lixy
authors.initials: L
authors.lastname: Yamada
authors.affiliation: Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan.
authors.forename: Yukie
authors.initials: Y
authors.lastname: Fujisaki
authors.affiliation: Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK.
authors.forename: Gareth
authors.initials: G
authors.lastname: Bloomfield
authors.affiliation: Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Yoshida
authors.affiliation: Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan.
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Kuwayama
authors.affiliation: Sugashima Marine Biological Laboratory, Graduate School of Science, Nagoya University, 429-63 Sugashima, Toba, Mie 517-0004, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Sawada
authors.affiliation: Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Mori
authors.affiliation: Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan. Electronic address: hideko@biol.tsukuba.ac.jp.
authors.forename: Hideko
authors.initials: H
authors.lastname: Urushihara
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D029681:Arabidopsis Proteins / Q000235:genetics / Q000502:physiology; D002352:Carrier Proteins / Q000235:genetics / Q000502:physiology; D002459:Cell Fusion; D004023:Dictyostelium / Q000235:genetics / Q000502:physiology*; D005306:Fertilization; D055786:Gene Knockout Techniques; D017125:Genes, Protozoan; D005854:Germ Cells / Q000502:physiology*; D010802:Phylogeny; D018521:Plant Physiological Phenomena; D020543:Proteome; D015800:Protozoan Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D013045:Species Specificity; D014170:Transformation, Genetic
chemical_list: D029681:Arabidopsis Proteins; D002352:Carrier Proteins; C548817:HAP2 protein, Arabidopsis; D020543:Proteome; D015800:Protozoan Proteins
keywords: Cell fusion protein; Dictyostelium discoideum; Fertilization; Macrocyst formation; Sex differentiation