タケウチ　マサキ   Takeuchi Masaki   竹内　雅貴    所属   川崎医療福祉大学  医療技術学部 臨床検査学科    職種   准教授
言語種別	英語
発表タイトル	Developmental Roles of siamois-related Gene in a Basal Actinopterygian: Functional and Evolutionary Implications
会議名	The 46th Annual Meeting for the Japanese Society of Developmental Biologists (cosponsor: the Asia-Pacific Developmental Biology Network)
学会区分	全国規模の学会
発表形式	口頭
講演区分	一般
発表者・共同発表者	◎Masaki Takeuchi, Shinichi Aizawa
発表年月日	2013/05/29
開催地 （都市, 国名）	Kunibiki Messe (Matsue, Japan)
概要	In Xenopus, siamois is essential to the formation of the Spemann’s organizer and mediates dorsal Wnt signaling. No siamois-related genes have been found yet in other taxa, but we found it in our bichir EST database. We named the bichir gene “dioskouroi (dios)” after the twin gods that became the symbol for Gemini. As well as siamois, dios has a strong axis-inducing activity in Xenopus embryos and acts as the transcriptional activator for secondary axis induction. Importantly, dios can also rescue the headless phenotype of siamois/twin double-knockdown embryos. Therefore, we identified bichir dios and Xenopus siamois as homologs. To confirm endogenous roles of dios in bichir embryogenesis, we performed depletion of dios by morpholino antisense microinjection. As results, bichir embryos were prevented gastrulation and form no embryonic axis and structures by dios-knockdown. These dios-knockdown phenotype of bichir embryos is much more severe than the headless phenotype by siamois/twin-knockdown in Xenopus embryos. In addition, it is revealed by the marker analysis that the endoderm differentiation also inhibited by dios-knockdown. Thus dios plays roles not only in organizer formation but also in endoderm differentiation in bichir, distinct from siamois in Xenopus. Based on these data, we will discuss about the evolution of siamois-related genes and their usage for early embryogenesis.