Azevedo Ana Sofia, Sousa Sara, Jacinto António, Saúde Leonor
Instituto de Medicina Molecular e Instituto de Histologia e Biologia do Desenvolvimento, Faculdade de Medicina da Universidade de Lisboa, Lisbon, 1649-028, Portugal.
BMC Dev Biol. 2012 Aug 25;12:24. doi: 10.1186/1471-213X-12-24.
Zebrafish has emerged as a powerful model organism to study the process of regeneration. This teleost fish has the ability to regenerate various tissues and organs like the heart, spinal cord, retina and fins. In this study, we took advantage of the existence of an excellent morphological reference in the zebrafish caudal fin, the bony ray bifurcations, as a model to study positional information upon amputation. We investigated the existence of positional information for bifurcation formation by performing repeated amputations at different proximal-distal places along the fin.
We show that, while amputations performed at a long distance from the bifurcation do not change its final proximal-distal position in the regenerated fin, consecutive amputations done at 1 segment proximal to the bifurcation (near the bifurcation) induce a positional reset and progressively shift its position distally. Furthermore, we investigated the potential role of Shh and Fgf signalling pathways in the determination of the bifurcation position and observed that they do not seem to be involved in this process.
Our results reveal that, an amputation near the bifurcation inhibits the formation of the regenerated bifurcation in the pre-amputation position, inducing a distalization of this structure. This shows that the positional memory for bony ray bifurcations depends on the proximal-distal level of the amputation.
斑马鱼已成为研究再生过程的一种强大的模式生物。这种硬骨鱼能够再生各种组织和器官，如心脏、脊髓、视网膜和鳍。在本研究中，我们利用斑马鱼尾鳍中存在的一个出色的形态学参考——骨射线分支，作为研究截肢后位置信息的模型。我们通过在鳍的不同近端 - 远端位置进行重复截肢，研究了分支形成的位置信息的存在情况。
我们发现，虽然在距离分支较远的位置进行截肢不会改变其在再生鳍中最终的近端 - 远端位置，但在分支近端 1 节处（靠近分支）连续进行截肢会引发位置重置，并使其位置逐渐向远端移动。此外，我们研究了 Sonic hedgehog（Shh）和成纤维细胞生长因子（Fgf）信号通路在确定分支位置中的潜在作用，发现它们似乎不参与这一过程。
我们的结果表明，在分支附近进行截肢会抑制截肢前位置再生分支的形成，导致该结构向远端化。这表明骨射线分支的位置记忆取决于截肢的近端 - 远端水平。
