Neurotrophic signaling regulates neural cell behaviors in development and physiology, although its role in regeneration has not been fully investigated. Here, we examined the role of neurotrophic signaling in Xenopus laevis tadpole tail regeneration. After the tadpole tails were amputated, the expression of neurotrophin ligand family genes, especially ngf and bdnf, was up-regulated as regeneration proceeded. Moreover, notochordal expression of the NGF receptor gene TrkA, but not that of other neurotrophin receptor genes TrkB and TrkC, became prominent in the regeneration bud, a structure arising from the tail stump after tail amputation. The regenerated tail length was significantly shortened by the pan-Trk inhibitor K252a or the TrkA inhibitor GW-441756, but not by the TrkB inhibitor ANA-12, suggesting that TrkA signaling is involved in elongation of regenerating tails. Furthermore, during Xenopus laevis embryonic development, TrkA expression was detected in the dorsal mesoderm at the gastrula stage and in the notochord at the neurula stage, and its knockdown led to gastrulation defects with subsequent shortening of the body axis length. These results suggest that Xenopus laevis TrkA signaling, which can act in the mesoderm/notochord, plays a key role in body axis elongation during embryogenesis as well as tail elongation during tadpole regeneration.

中文翻译：

---

TrkA信号在非洲爪蟾t尾部再生和早期胚胎发育过程中的作用。

神经营养信号调节神经细胞在发育和生理中的行为，尽管其在再生中的作用尚未得到充分研究。在这里，我们检查了非洲爪蟾t尾神经再生中神经营养信号的作用。剪除the尾后，随着再生的进行，神经营养蛋白配体家族基因（尤其是ngf和bdnf）的表达上调。此外，NGF受体基因TrkA的脊索表达在再生芽中变得突出，而其他神经营养蛋白受体基因TrkB和TrkC则不表达。pan-Trk抑制剂K252a或TrkA抑制剂GW-441756显着缩短了再生的尾巴长度，但TrkB抑制剂ANA-12却没有，提示TrkA信号传导参与再生尾巴的延长。此外，在非洲爪蟾胚胎发育过程中，在胃小肠期的背中胚层和神经节的脊索中检测到TrkA表达，其敲低导致胃泌素缺陷，随后缩短了体轴长度。这些结果表明，非洲爪蟾TrkA信号传导可在中胚层/脊索中起作用，在胚胎发生过程中体轴伸长以及t再生过程中的尾巴伸长中起关键作用。并且其击倒导致胃排毒缺陷，随后缩短体轴长度。这些结果表明，非洲爪蟾TrkA信号传导可在中胚层/脊索中起作用，在胚胎发生过程中体轴伸长以及t再生过程中的尾巴伸长中起关键作用。并且其击倒导致胃排毒缺陷，随后缩短体轴长度。这些结果表明，非洲爪蟾TrkA信号传导可在中胚层/脊索中起作用，在胚胎发生过程中体轴伸长以及t再生过程中的尾巴伸长中起关键作用。