Generic injuries are sufficient to induce ectopic Wnt organizers in Hydra

During whole-body regeneration, a bisection injury can trigger two different types of regeneration. To understand the transcriptional regulation underlying this adaptive response we characterized transcript abundance and chromatin accessibility during oral and aboral regeneration in the cnidarian Hydra vulgaris. We found that the initial response to amputation at both wound sites is identical and includes widespread apoptosis and the activation of the oral-specifying Wnt signaling pathway. By 8 hours post-amputation, Wnt signaling became restricted to oral regeneration. Wnt pathway genes were also upregulated in puncture wounds and these wounds induced the formation of ectopic oral structures if pre-existing organizers were simultaneously amputated. Our work suggests that oral patterning is activated as part of a generic injury response in Hydra, and that alternative injury outcomes are dependent on signals from the surrounding tissue. Furthermore, Wnt signaling is likely part of a cons...

在整体再生过程中，切割损伤可触发两种不同类型的再生反应。为解析这一适应性响应背后的转录调控机制，我们对刺胞动物普通水螅（Hydra vulgaris）的口侧与反口侧再生过程中的转录本丰度及染色质可及性进行了系统表征。研究发现，两处伤口位点对截肢的初始响应完全一致，均包含广泛的细胞凋亡事件以及口部特异性Wnt信号通路的激活。截肢后8小时，Wnt信号通路的活性被限定于口侧再生过程中。Wnt通路基因在穿刺损伤中同样被上调；若同时切除预先存在的组织者中心，此类穿刺损伤可诱导异位口部结构的形成。本研究表明，口部模式建成的激活是水螅通用损伤响应的一部分，而不同的损伤结局则依赖于周围组织传递的信号。此外，Wnt信号通路很可能是保守损伤响应程序的组成部分。