BACKGROUND Urodele amphibians are capable of regenerating their organs after severe damage. During such regeneration, participating cells are given differentiation instructions by the surrounding cells. Limb regeneration has been investigated as a representative phenomenon of organ regeneration. Cells known as blastema cells are induced after limb amputation. In this process, dermal fibroblasts are dedifferentiated and become undifferentiated similar to limb bud cells. Just like limb bud cells, the induced blastema cells are positioned along the three limb developmental axes: the dorsoventral, the anteroposterior, and the proximodistal. The accurate developmental axes are essential for reforming the structures correctly. Despite the importance of the developmental axes, the relationship between the newly establishing developmental axes and existing limb axes was not well described with molecular markers. RESULTS In this study, we grafted skin from GFP-transgenic axolotls and traced the cell lineage with position-specific gene expressions in order to investigate the correlation of the newly established axes and cellular origin. Shh- and Lmx1b-expressing cells emerged from the posterior skin and dorsal skin, respectively, even though the skin was transplanted to an inconsistent position. Shox2, a posterior marker gene, could be activated in cells derived from distal skin. CONCLUSIONS Our results suggest that the location memories on anteroposterior and dorsoventral axes are relatively stable in a regenerating blastema though cellular differentiation is reprogrammed.

中文翻译：

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墨西哥Ambystoma肢体再生过程中位置记忆的稳定性和可塑性。

背景技术Urodele两栖动物能够在严重损伤后再生其器官。在这种再生过程中，周围的细胞会向参与细胞发出分化指示。肢体再生已被研究为器官再生的代表现象。肢体截肢后诱导称为胚细胞的细胞。在此过程中，真皮成纤维细胞与肢芽细胞一样被去分化并变得未分化。就像肢芽细胞一样，诱导的胚泡细胞沿着三个肢体发育轴定位：背腹，前后，前肢。正确的显影轴对于正确地重组结构至关重要。尽管发展轴很重要，新建立的发育轴和现有肢体轴之间的关系并没有用分子标记很好地描述。结果在这项研究中，我们从GFP转基因的轴索移植皮肤，并用位置特异性基因表达追踪细胞谱系，以研究新建立的轴与细胞起源的相关性。即使将皮肤移植到不一致的位置，Shh和Lmx1b表达细胞也分别从后部皮肤和背侧皮肤出现。后部标记基因Shox2可在源自远端皮肤的细胞中被激活。结论我们的结果表明，尽管细胞分化被重新编程，但在再生胚泡中，前后腹轴上的位置记忆相对稳定。