Planarian Hedgehog/Patched establishes anterior–posterior polarity by regulating Wnt signaling
スポンサーリンク
概要
- 論文の詳細を見る
100年来の謎に迫る－体の極性を決める仕組みを解明しました. 京都大学プレスリリース. 2009-12-08. http://www.kyoto-u.ac.jp/ja/news_data/h/h1/news6/2009/091208_2.htmDespite long-standing interest, the molecular mechanisms underlying the establishment of anterior–posterior (AP) polarity remain among the unsolved mysteries in metazoans. In the planarians (a family of flatworms), canonical Wnt/β-catenin signaling is required for posterior specification, as it is in many animals. However, the molecular mechanisms regulating the posterior-specific induction of Wnt genes according to the AP polarity have remained unclear. Here, we demonstrate that Hedgehog (Hh) signaling is responsible for the establishment of AP polarity via its regulation of the transcription of Wnt family genes during planarian regeneration. We found that RNAi gene knockdown of Dugesia japonica patched (Djptc) caused ectopic tail formation in the anterior blastema of body fragments, resulting in bipolar-tails regeneration. In contrast, RNAi of hedgehog (Djhh) and gli (Djgli) caused bipolar-heads regeneration. We show that Patched-mediated Hh signaling was crucial for posterior specification, which is established by regulating the transcription of Wnt genes via downstream Gli activity. Moreover, differentiated cells were responsible for the posterior specification of undifferentiated stem cells through Wnt/β-catenin signaling. Surprisingly, Djhh was expressed in neural cells all along the ventral nerve cords (along the AP axis), but not in the posterior blastema of body fragments, where the expression of Wnt genes was induced for posteriorization. We therefore propose that Hh signals direct head or tail regeneration according to the AP polarity, which is established by Hh signaling activity along the body's preexisting nervous system.
- 2009-12-11
論文 | ランダム
- 国会職員「時代錯誤の既得権」是正を急げ--国家公務員随一のぬるま湯
- 躍動アジア(中台) 時代錯誤の「反国家分裂法」
- フジテレビが絶対伝えないホリエモンつぶしの「時代錯誤」 (総力特集「株マジック」)
- 通信 時代錯誤 戦略なき総務省に振り回されるNTTの危機
- 宇宙時代における時代錯誤的理科教育からの脱却 : 小・中・高校一貫した視点で学習指導要領の作成を