Bando Tetsuya, Mito Taro, Maeda Yuko, Nakamura Taro, Ito Fumiaki, Watanabe Takahito, Ohuchi Hideyo, Noji Sumihare
Department of Life Systems, Institute of Technology and Science, The University of Tokushima Graduate School, 2-1 Minami-Jyosanjima-cho, Tokushima city, 770-8506, Japan.
Development. 2009 Jul;136(13):2235-45. doi: 10.1242/dev.035204. Epub 2009 May 27.
An amputated cricket leg regenerates all missing parts with normal size and shape, indicating that regenerating blastemal cells are aware of both their position and the normal size of the leg. However, the molecular mechanisms regulating this process remain elusive. Here, we use a cricket model to show that the Dachsous/Fat (Ds/Ft) signalling pathway is essential for leg regeneration. We found that knockdown of ft or ds transcripts by regeneration-dependent RNA interference (rdRNAi) suppressed proliferation of the regenerating cells along the proximodistal (PD) axis concomitantly with remodelling of the pre-existing stump, making the regenerated legs shorter than normal. By contrast, knockdown of the expanded (ex) or Merlin (Mer) transcripts induced over-proliferation of the regenerating cells, making the regenerated legs longer. These results are consistent with those obtained using rdRNAi during intercalary regeneration induced by leg transplantation. We present a model to explain our results in which the steepness of the Ds/Ft gradient controls growth along the PD axis of the regenerating leg.
一只被截肢的蟋蟀腿能再生出所有缺失的部分，且大小和形状正常，这表明再生芽基细胞既知道自己的位置，也知道腿的正常大小。然而，调节这一过程的分子机制仍然难以捉摸。在这里，我们使用蟋蟀模型来表明，Dachsous/Fat（Ds/Ft）信号通路对腿的再生至关重要。我们发现，通过依赖再生的RNA干扰（rdRNAi）敲低ft或ds转录本，会抑制再生细胞沿近端到远端（PD）轴的增殖，同时伴随着原有残端的重塑，使再生腿比正常腿短。相比之下，敲低扩展（ex）或默林（Mer）转录本会诱导再生细胞过度增殖，使再生腿更长。这些结果与在腿部移植诱导的居间再生过程中使用rdRNAi获得的结果一致。我们提出了一个模型来解释我们的结果，即Ds/Ft梯度的陡度控制着再生腿沿PD轴的生长。
