title: Transcriptional pattern of a novel gene, expressed specifically after the point-of-no-return during sexualization, in planaria.
abstract: We have investigated sexualization of asexual worms in the planarian Dugesia ryukyuensis. During sexualization there is a point from which an animal cannot return to the asexual state (point-of-no-return). To isolate the genes related to the point-of-no-return, we performed differential screening and isolated one novel gene that was expressed specifically in yolk glands of the worms after the point-of-no-return and named it Dryg. It encoded 655 amino acids with a predicted molecular mass of 79 kDa. We performed a series of experiments using Dryg as a molecular marker in the yolk gland. At first, we monitored how the yolk gland was formed during sexualization. The expression in sexualizing worms at stage 3 is limited to a single type of cell that has characteristics of neoblasts, the totipotent somatic cells; however, the expression is observed in the yolk gland in sexualized worms. Furthermore, we monitored yolk glands for expression during regeneration. The original yolk glands seem to disappear after ablation, then new yolk glands appeared along the ventral nerve cords. Because this expression pattern looks like that of sexualizing worms at stage 3, we speculate that yolk gland cells may differentiate from neoblasts during regeneration as observed during sexualization.
authors.affiliation: Department of Biological Sciences, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama, Kanagawa 226-8501, Japan.
authors.forename: Sumitaka
authors.initials: S
authors.lastname: Hase
authors.forename: Kazuya
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Ryo
authors.initials: R
authors.lastname: Koyanagi
authors.forename: Motonori
authors.initials: M
authors.lastname: Hoshi
authors.forename: Midori
authors.initials: M
authors.lastname: Matsumoto
mesh_terms: D000818:Animals; D001685:Biological Factors / Q000494:pharmacology; D018507:Gene Expression Regulation, Developmental; D017238:Genes, Helminth; D010932:Planarians / Q000235:genetics* / Q000254:growth & development / Q000502:physiology*; D012038:Regeneration; D012098:Reproduction / Q000187:drug effects / Q000502:physiology*; D012100:Reproduction, Asexual / Q000187:drug effects / Q000502:physiology; D013997:Time Factors; D014158:Transcription, Genetic
chemical_list: D001685:Biological Factors