A clonal analysis of neural progenitors during axolotl spinal cord regeneration reveals evidence for both spatially restricted and multipotent progenitors
A clonal analysis of neural progenitors during axolotl spinal cord regeneration reveals evidence for both spatially restricted and multipotent progenitors
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DOI：
10.1242/dev.02852
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发表时间：
2007-06-01
期刊：
影响因子：
4.6
通讯作者：
Tanaka, Elly M.
中科院分区：
文献类型：
--
作者：
Mchedlishvili, Levan;Epperlein, Hans H.;Tanaka, Elly M.
脊髓的完全再生发生在尾再生后的有尾目两栖动物，如美西螈。关于神经前体细胞如何从成熟的尾部募集，它们如何填充再生的脊髓，以及神经前体细胞是否是多能的，我们知之甚少。为了解决这些问题，我们使用了三种类型的细胞命运映射。通过移植绿色荧光蛋白阳性（GFP（+））脊髓，我们表明，一个500 μ m的区域邻近截肢平面产生神经祖细胞再生。我们进一步跟踪单核GFP标记的细胞，因为它们在再生过程中增殖，观察它们的空间分布，并最终观察它们的祖细胞标志物PAX 7和PAX 6的表达。大多数祖细胞产生的后代沿着前/后（A/P）轴沿着扩展，但仍然靠近亲本的背/腹（D/V）位置。少数克隆跨越多个D/V结构域，占据不同的分子身份，表明细胞可以在体内执行多能性。在平行实验中，批量标记的背侧或腹侧限制的祖细胞显示，腹侧细胞在再生脊髓的远端开关背侧细胞的命运。PAX 7和PAX 6表达沿着再生脊髓的分析表明，这些标记物表达在背侧和侧域中，除了在远端末端之外，所有沿着脊髓。这些结果表明，神经祖细胞的身份是不稳定的或改变的终端囊泡区域，其中明确的迁移到周围的芽基细胞也被观察到。
Complete regeneration of the spinal cord occurs after tail regeneration in urodele amphibians such as the axolotl. Little is known about how neural progenitor cells are recruited from the mature tail, how they populate the regenerating spinal cord, and whether the neural progenitor cells are multipotent. To address these issues we used three types of cell fate mapping. By grafting green fluorescent protein-positive ( GFP(+)) spinal cord we show that a 500 mu m region adjacent to the amputation plane generates the neural progenitors for regeneration. We further tracked single nuclear-GFP-labeled cells as they proliferated during regeneration, observing their spatial distribution, and ultimately their expression of the progenitor markers PAX7 and PAX6. Most progenitors generate descendents that expand along the anterior/posterior (A/P) axis, but remain close to the dorsal/ventral (D/V) location of the parent. A minority of clones spanned multiple D/V domains, taking up differing molecular identities, indicating that cells can execute multipotency in vivo. In parallel experiments, bulk labeling of dorsally or ventrally restricted progenitor cells revealed that ventral cells at the distal end of the regenerating spinal cord switch to dorsal cell fates. Analysis of PAX7 and PAX6 expression along the regenerating spinal cord indicated that these markers are expressed in dorsal and lateral domains all along the spinal cord except at the distal terminus. These results suggest that neural progenitor identity is destabilized or altered in the terminal vesicle region, from which clear migration of cells into the surrounding blastema is also observed.