title: Exogastrulation and interference with the expression of major yolk protein by estrogens administered to sea urchins.
abstract: Although estrogens have been detected in some echinoderm species, their role is not clearly understood; so we examined the effects of estrogens administered to sea urchin embryos and larvae. A typical malformation was exogastrulation, induced by the exposure to ethynylestradiol (EER) in a defined period of 12 h from 12 h after fertilization (HAF). Morphogenesis for gastrulation was delayed in the treated embryos: protrusion of the archenteron started at 30 HAF when gastrulation had already finished in normal embryos. Exogastrulation induced by EER was cancelled by the antiestrogen chemical, ICI182,780. Feeding larvae were less sensitive to estrogens than those in early embryogenesis and, at certain concentrations, developed without abnormal morphology. The effect of estrogens was examined at the level of gene expression of the major yolk protein (MYP). MYP expression started during the larval stage and was suppressed by estrone at the six-armed stage, but not by beta-estradiol, and in later stage larvae, the expression was not affected by treatment with either estrogen. Estrogens affect sea urchins in the early stage of embryogenesis, leading to abnormal morphogenesis and interference with gene expression.
authors.affiliation: Tateyama Marine Laboratory, Marine and Coastal Research Center, Ochanomizu University, Tateyama, Chiba, Japan. kiyomoto.masato@ocha.ac.jp
authors.forename: Masato
authors.initials: M
authors.lastname: Kiyomoto
authors.forename: Ayumi
authors.initials: A
authors.lastname: Kikuchi
authors.forename: Seiko
authors.initials: S
authors.lastname: Morinaga
authors.forename: Tatuya
authors.initials: T
authors.lastname: Unuma
authors.forename: Yukio
authors.initials: Y
authors.lastname: Yokota
mesh_terms: D000818:Animals; D004527:Egg Proteins / Q000235:genetics / Q000378:metabolism*; D004530:Egg Yolk / Q000187:drug effects / Q000378:metabolism*; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000187:drug effects; D004997:Ethinyl Estradiol / Q000008:administration & dosage* / Q000633:toxicity*; D054262:Gastrulation / Q000187:drug effects*; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D007814:Larva / Q000378:metabolism; D012617:Sea Urchins / Q000187:drug effects* / Q000196:embryology*
chemical_list: D004527:Egg Proteins; D004997:Ethinyl Estradiol