Title:
脚再生の分子メカニズムーモデル昆虫を用いた研究
Molecular mechanisms underlying insect leg regeneration

Sumihare Noji
The University of Tokushima , Vice President
noji@tokushima-u.ac.jp

Abstract:
The nymphs of cricket Gryllus bimaculatus possess the ability to regenerate amputated legs. We have asked how limb size and shape is regulated during regeneration. Recently, the protocadherin Dachsous/Fat (Ds/Ft) signaling pathway has been found to be essential for wing development of the fly and leg regeneration of the cricket. The Ds-Ft signaling pathway is linked to the Warts/Hippo (Wts/Hpo) signaling pathway, leading to cell proliferation. Several lines of evidence have suggested that the Wts/Hpo signaling pathway is involved in the control of organ size, and that this pathway is regulated by Ds-Ft and Merlin-Expanded, which are linked to morphogens such as decapentaplegic/bone morphogenic protein, Wingless/Wnt and a ligand of epidermal growth factor receptor. Here we review recent progress in elucidating mechanisms controlling leg size and shape in insects and vertebrates, focusing on the Ds/Ft signaling pathway. We also introduce a working model, Ds/Ft steepness model, to explain how steepness of the Ds-Ft gradient controls leg size along the proximodistal axis.

コオロギの脚を幼虫期に切断すると、増殖能の高い脱分化した細胞からなる再生芽が脚の遠位端に形成され、再生芽細胞の増殖により失われた部分が付加的に再生される。再生芽の形成や再生芽細胞の増殖を制御する分子メカニズムを解明するため、研究を行っている。切断された脚が再生し、正常なサイズになる過程に、プロトカドヘリンである Fat/DachsousとHippoシグナル伝達経路が関係していることがわかった。このメカニズムは脊椎動物にも存在するかもしれない。最近の成果を講演する。