Yokoyama Hitoshi, Tamura Koji, Ide Hiroyuki
Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai, Japan.
Dev Dyn. 2002 Nov;225(3):277-88. doi: 10.1002/dvdy.10155.
We previously showed that recombinant limb buds with dissociated and reaggregated mesenchyme develop more than 30 digits in Xenopus laevis, which exhibits different capacities for limb regeneration at different developmental stages (Yokoyama et al. [1998] Dev Biol 196:1-10). Cell-cell contact among anterior- and posterior-derived mesenchymal cells is required for anteroposterior (AP) axis formation of recombinant limbs in an intercalary manner. However, whether one-way induction from posterior cells to anterior cells as proposed by the polarizing zone model or interactions between anterior and posterior cells evoke the AP axis formation in recombinant limbs remains unclear. In this study, we found, by a combination of X-ray irradiation and a recombinant limb technique, that not one-way induction but interactions between anterior and posterior cells accompanied by cell contribution are indispensable for AP axis formation in recombinant limbs. Shh was expressed in posterior-derived not anterior-derived cells. We propose that the recombinant limb is an excellent model for examining the axis formation mechanism in regenerating limbs because, as in recombinant limbs, cell-cell contact among cells derived from different positions of an amputation plane occurs in the blastema of regenerating limbs.
我们之前表明，在非洲爪蟾中，具有解离并重新聚集的间充质的重组肢芽发育出了超过30根指（趾），非洲爪蟾在不同发育阶段表现出不同的肢体再生能力（横山等人，[1998]《发育生物学》196:1 - 10）。前后端来源的间充质细胞之间的细胞 - 细胞接触以插入方式参与重组肢体前后（AP）轴的形成。然而，极化区模型所提出的从后端细胞向前端细胞的单向诱导，还是前后端细胞之间的相互作用引发了重组肢体的AP轴形成，仍不清楚。在本研究中，我们通过X射线照射和重组肢体技术相结合发现，对于重组肢体的AP轴形成而言，并非单向诱导，而是伴随着细胞贡献的前后端细胞之间的相互作用是不可或缺的。Shh在后端来源而非前端来源的细胞中表达。我们提出，重组肢体是研究再生肢体轴形成机制的一个极佳模型，因为与重组肢体一样，再生肢体的芽基中会发生来自截肢平面不同位置的细胞之间的细胞 - 细胞接触。
