Origin and development of striated muscles in the tail of axolotl embryos

脊椎动物尾轴（神经管、脊索、表皮、体节）的形成机制与躯干不同。因此，研究尾巴的形成可以深入了解不同发育程序的灵活性。例如，横纹尾肌不是从躯干体节募集的，而是从后神经胚的神经板和神经褶募集的。在分子水平上尚不清楚这些组织最初是否被指定为后来成为中胚层命运的神经转移或代表多能干细胞。使用蝾螈（Ambystoma mexicanum）作为实验模型，该建议主要集中在识别后神经板和后神经褶/神经嵴（NC）组织的异位组织移植和原位杂交的中胚层与神经元的字符。此外，将通过将来自转基因（GFP+和Cherry+）蝾螈供体的组织片段移植到白色宿主中并通过研究它们在宿主尾部的分布来研究后神经板和神经褶/NC对横纹尾肌的详细和单独的贡献。将通过转基因动物研究横纹尾肌的NC起源。该提案的另一个重要目标是导致尾部形成的细胞和组织相互作用。它们将在单细胞水平上用免疫组织化学和分子生物学进行分析。我们的专业知识和新开发的标记方法将提供被忽视的领域内的脊椎动物尾部形成的神经与中胚层诱导模型的进展。

Mechanisms of axis (neural tube, notochord, epidermis, somites) formation in the vertebrate tail di-verge from those in the trunk. Thus, studying tail formation can provide insight into the flexibility of different developmental programs. For example, striated tail muscle is not recruited from trunk somites but from neural plate and neural fold of the posterior neurula. It is unknown on a molecular level whether these tissues originally specified to become neural divert to mesodermal fates later or represent pluripotent stem cells. Using the axolotl (Ambystoma mexicanum) as experimental model this proposal focuses mainly on identifying the mesodermal versus neuronal character of the posterior neural plate and posterior neural fold/neural crest (NC) tissues by ectopic tissue grafting and by in situ hybridization. Furthermore, the detailed and separate contribution of posterior neural plate and neural fold/NC to striated tail muscle will be investigated by grafting tissue fragments from transgenic (GFP+ and Cherry+) axolotl donors into white hosts and by studying their distribution in the host tail. The NC origin of striated tail muscles will be investigated via transgenic animals. Another important objective of the proposal are the cell and tissue interactions leading to tail formation. They will be analyzed on a single cell level with immunohistochemistry and molecular biology. Our expertise and the newly developed labelling methods will provide progress within the neglected field of vertebrate tail formation as a model for neural versus mesodermal induction.