Yakushiji Nayuta, Suzuki Makoto, Satoh Akira, Ide Hiroyuki, Tamura Koji
Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aobayama Aoba-ku, Sendai, Japan.
Dev Dyn. 2009 Aug;238(8):1887-96. doi: 10.1002/dvdy.22011.
Regenerating limbs of urodele amphibians and Xenopus tadpole are reconstructed along proximal-distal, anterior-posterior (AP), and dorsal-ventral axes. In contrast, a regenerated limb of the Xenopus froglet does not have digits, and only a simple cartilaginous structure referred to as a "spike" is formed. This suggests that repatterning along the AP axis is absent in the froglet blastema. Previous studies have shown that Shh and its target genes are not expressed in the froglet blastema. In this study, we activated Hedgehog signaling in the froglet blastema and found that target genes of Shh were inducible in the mesenchyme of limb blastema. Furthermore, we found that activation of the signaling had effects on blastema cell proliferation and chondrogenesis and resulted in the formation of multiple cartilaginous structures. These findings indicate that activation of signaling that is absent in the froglet blastema is effective for improvement of limb regeneration ability in the Xenopus froglet.
有尾两栖动物和非洲爪蟾蝌蚪再生的肢体是沿着近端-远端、前后(AP)和背腹轴进行重建的。相比之下,非洲爪蟾幼蛙再生的肢体没有趾,仅形成一种被称为“钉状物”的简单软骨结构。这表明非洲爪蟾幼蛙芽基中不存在沿前后轴的模式重排。先前的研究表明,音猬因子(Shh)及其靶基因在非洲爪蟾幼蛙芽基中不表达。在本研究中,我们在非洲爪蟾幼蛙芽基中激活了Hedgehog信号通路,发现Shh的靶基因在肢体芽基的间充质中是可诱导的。此外,我们发现该信号通路的激活对芽基细胞增殖和软骨形成有影响,并导致多个软骨结构的形成。这些发现表明,激活非洲爪蟾幼蛙芽基中缺失的信号通路对提高非洲爪蟾幼蛙的肢体再生能力是有效的。