Yoshida Takafumi, Kawakami Atsushi
School of Life Science and Technology, Institute of Science Tokyo, Yokohama, Japan.
Dev Growth Differ. 2025 Apr;67(3):174-181. doi: 10.1111/dgd.12962. Epub 2025 Feb 1.
Previous studies have shown that tissue regeneration induces expression of genes that play important roles in regeneration. Recently, several studies have identified regeneration-response enhancers (RREs) that activate gene expression by tissue injury. Particularly, we showed that RREs contain two transcription factor-binding motifs: a bHLH transcription factor-binding motif, an E-box, and an AP-1/bZIP transcription factor-binding motif, a 12-O-Tetradecanoylphorbol 13-acetate response element (TRE). However, the triggers and subsequent signals generated by injury are still unclear. In this study, we analyzed RRE activation using various injury models. Although inter-ray incisions and skin exfoliation injuries did not activate RREs or regeneration genes, the fin puncture injury activated RREs and several regeneration-response genes. After fin puncture injury, msxc was activated only on the proximal side of the hole where blastema-like tissue was formed, whereas RREs, junbb, and fibronectin 1b (fn1b) were activated on both the proximal and distal sides, implying that activation of RREs, junbb, and fn1b is independent of blastema formation. Here, we also established a mild cryoinjury method. After this injury, transient vascular destruction, an increase in cell death, and an accumulation of myeloid cells were observed; however, no major morphological damage was observed. Importantly, msxc was not induced by cryoinjury, whereas fn1b, junbb, and 1.8 k RRE (-1.8 kb promoter of fn1b) were activated, suggesting that cryoinjury induces the responses of fn1b, junbb, and 1.8 k RRE without forming the blastema. Thus, our study shows that the cryoinjury model and the RRE transgenic (Tg) zebrafish may provide a useful platform for exploring injury signals.
先前的研究表明，组织再生会诱导在再生过程中发挥重要作用的基因表达。最近，多项研究鉴定出了通过组织损伤激活基因表达的再生反应增强子（RRE）。特别是，我们发现RRE包含两个转录因子结合基序：一个bHLH转录因子结合基序，即E盒，以及一个AP-1/bZIP转录因子结合基序，即12-氧-十四烷酰佛波醇-13-乙酸酯反应元件（TRE）。然而，损伤引发的触发因素及后续信号仍不清楚。在本研究中，我们使用各种损伤模型分析了RRE的激活情况。虽然鳍条间切口和皮肤剥脱损伤未激活RRE或再生基因，但鳍穿刺损伤激活了RRE和几个再生反应基因。鳍穿刺损伤后，msxc仅在形成芽基样组织的孔的近端被激活，而RRE、junbb和纤连蛋白1b（fn1b）在近端和远端均被激活，这意味着RRE、junbb和fn1b的激活与芽基形成无关。在此，我们还建立了一种轻度冷冻损伤方法。这种损伤后，观察到短暂的血管破坏、细胞死亡增加和髓样细胞积累；然而，未观察到严重的形态学损伤。重要的是，冷冻损伤未诱导msxc表达，但激活了fn1b、junbb和1.8 k RRE（fn1b的-1.8 kb启动子），表明冷冻损伤诱导了fn1b、junbb和1.8 k RRE的反应而未形成芽基。因此，我们的研究表明，冷冻损伤模型和RRE转基因（Tg）斑马鱼可能为探索损伤信号提供一个有用的平台。
