title: Wnt, Frizzled, and sFRP gene expression patterns during gastrulation in the starfish Patiria (Asterina) pectinifera.
abstract: By the initial phase of gastrulation, Wnt pathway regulation mediates endomesoderm specification and establishes the animal-vegetal axis, thereby leading to proper gastrulation in starfish. To provide insight into the ancestral mechanism regulating deuterostome gastrulation, we identified the gene expression patterns of Wnt, Frizzled (Fz), and secreted frizzled-related protein (sFRP) family genes, which play a role in the initial stage of the Wnt pathway, in starfish Patiria (Asterina) pectinifera embryos using whole mount in situ hybridization. We identified ten Wnt, four Fz, and two sFRP paralogues. From the hatching blastula to the late gastrula stage, the majority of the Wnt genes and both Fz5/8 and sFRP1/5 were expressed in the posterior and anterior half of the embryo, respectively. Wnt8, Fz1, and Fz4 showed restricted expression in the lateral ectoderm. On the other hand, several genes were expressed de novo in the restricted domain of the archenteron at the late gastrula stage. These results suggest that the canonical and/or non-canonical Wnt pathway might implicate endomesoderm specification, anterior-posterior axis establishment, anterior-posterior patterning, and archenteron morphogenesis in the developmental context of starfish embryos. From comparison with the expression patterns observed in Patria miniata, we consider that the Wnt pathway is conserved among starfishes.
authors.affiliation: Department of Biology, Research and Education Center for Natural Sciences, Keio University, 4-1-1 Hiyoshi, Kohoku-ku, Yokohama, 223-8521, Japan. Electronic address: nkawai@a7.keio.jp.
authors.forename: Narudo
authors.initials: N
authors.lastname: Kawai
authors.affiliation: Department of Biology, Research and Education Center for Natural Sciences, Keio University, 4-1-1 Hiyoshi, Kohoku-ku, Yokohama, 223-8521, Japan.
authors.forename: Ritsu
authors.initials: R
authors.lastname: Kuraishi
authors.affiliation: Department of Biology, Research and Education Center for Natural Sciences, Keio University, 4-1-1 Hiyoshi, Kohoku-ku, Yokohama, 223-8521, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kaneko
mesh_terms: D000818:Animals; D004625:Embryo, Nonmammalian; D019143:Evolution, Molecular; D051157:Frizzled Receptors / Q000096:biosynthesis* / Q000235:genetics; D005775:Gastrula / Q000254:growth & development / Q000378:metabolism; D054262:Gastrulation / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D036341:Intercellular Signaling Peptides and Proteins / Q000096:biosynthesis* / Q000235:genetics; D009024:Morphogenesis / Q000235:genetics; D010802:Phylogeny; D013215:Starfish / Q000235:genetics* / Q000254:growth & development; D051153:Wnt Proteins / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D051157:Frizzled Receptors; D036341:Intercellular Signaling Peptides and Proteins; D051153:Wnt Proteins
keywords: Embryo; Expression pattern; Frizzled; Starfish; Wnt; sFRP