A protodermal miR394 signal defines a region of stem cell competence in the Arabidopsis shoot meristem

原胚层 miR394 信号定义了拟南芥芽分生组织中干细胞活性的区域

• 批准号: 239011438
• 负责人: Professor Dr. Thomas Laux
• 金额: --
• 依托单位: Institut für Biologie III
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2013
• 资助国家: 德国
• 起止时间: 2012-12-31 至 2018-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/239011438?language=en
• 关键词: protodermal; miR394; signal; defines; region

Plants form new organs throughout their life, which in extreme cases can last more than a thousands years, by the activity of pluripotent stem cells in their growth centers, the meristems. Unraveling the mechanisms that maintain meristem activity is central to understand plant growth and development. To maintain shoot growth, the spatial organization of the shoot meristem, which gives rise to all aerial organs, must be stably preserved despite the fact that all meristem cells divide and differentiating cells leave the meristem. The stem cell niche is positioned at the outermost cell layers in the shoot meristem center, whereas a differentiation occurs in the surrounding areas. The shoot meristem thus represents a fundamental problem in biology, the maintenance of a functional organisation in a dividing cell population. In conventional genetic screens, factors fixing stem cell competence to the tip of the plant have not been discovered, presumably due to genetic redundancy. To circumvent this limitation, we performed several genetic enhancer and suppressor screens for novel stem cell regulators in the model plant Arabidopsis thaliana in our preparatory work for this proposal. We discovered through the analysis of one mutant that the protoderm (the outermost layer of the shoot meristem) functions as a hitherto unknown signaling center in stem cell regulation. It supplies the microRNA miR394 in a gradient to the underlying stem cells, where miR394 inhibits the F-Box protein LEAF CURLING RESPONSIVENESS (LCR). This repression is necessary to enable stem cell maintenance through the transcription factor WUSCHEL (WUS), which moves upward from underneath the stem cells. The implication of these findings is that the protoderm as the outermost cell layer of the shoot meristem can act as a stable source of patterning information, although its resident cells may change. The interaction of inward (miR394) and outward (WUS) signals produced from opposite poles of the stem cell population provides a novel concept for how the stem cell niche is stably anchored in the self organizing shoot meristem. The goal of this proposal is to investigate the molecular mechanisms of how miR394 regulates the region of stem cell competence in the shoot meristem. We will explore the spatial, temporal, and dosimetric parameters of miR394 function, integrate miR394 signaling into the regulatory network of the shoot meristem, and investigate the molecular mechanism of how LCR inhibits stem cell fate. The results obtained from this project will also be used in collaboration with Prof. Fleck (Wageningen) to develop mathematical models for shoot meristem maintenance. This project will not only address a fundamental question in stem cell biology, but also has the potential to contribute to our understanding of stem cell-based regeneration strategies in economically important plants.

植物通过其生长中心分生组织中的多能干细胞的活动，在它们的一生中形成新的器官，在极端情况下，这种器官可以持续数千年以上。解开维持分生组织活性的机制是了解植物生长和发育的核心。为了保持芽的生长，尽管所有的分生组织细胞分裂，分化细胞离开分生组织，但形成所有气生器官的茎分生组织的空间组织必须得到稳定的保存。干细胞生态位位于芽分生组织中心最外层的细胞层，而分化发生在周围区域。因此，茎分生组织代表了生物学中的一个基本问题，即在分裂的细胞群体中维持一个功能组织。在传统的基因筛查中，尚未发现将干细胞能力固定在植物顶端的因素，可能是由于遗传冗余。为了绕过这一限制，我们在模式植物拟南芥中对新型干细胞调节因子进行了几次遗传增强子和抑制子筛选，为这一提案做了准备工作。通过对一个突变体的分析，我们发现原真皮(茎分生组织的最外层)在干细胞调节中起着迄今未知的信号中心的作用。它以梯度的方式将microRNA miR394提供给底层干细胞，其中miR394抑制F-Box蛋白的卷叶反应(LCR)。这种抑制是通过转录因子WUSCHEL(WUS)维持干细胞所必需的，转录因子WUSCHEL从干细胞下方向上移动。这些发现的含义是，作为茎分生组织最外层的原真皮可以作为构图信息的稳定来源，尽管其驻留细胞可能会发生变化。干细胞种群相对两极产生的向内(MiR394)和向外(WUS)信号的相互作用为干细胞生态位如何稳定地固定在自组织的茎分生组织中提供了一个新的概念。这项建议的目的是研究miR394如何调节茎分生组织中干细胞能力区域的分子机制。我们将探索miR394功能的空间、时间和剂量学参数，将miR394信号整合到茎分生组织的调控网络中，并研究LCR抑制干细胞命运的分子机制。从这个项目中获得的结果也将用于与Fleck教授(Wageningen)合作开发新芽分生组织维持的数学模型。这个项目不仅将解决干细胞生物学中的一个基本问题，而且有可能有助于我们理解在经济上重要的植物中基于干细胞的再生策略。

项目成果

Integration of pluripotency pathways regulates stem cell maintenance in the Arabidopsis shoot meristem

多能性途径的整合调节拟南芥芽分生组织中干细胞的维持

• DOI: 10.1073/pnas.2015248117
• 发表时间: 2020
• 期刊: Proceedings of the National Academy of Sciences
• 作者: Ying Hua Su;Chao Zhou;Ying Ju Li;Yang Yu;Li Ping Tang;Wen Jie Zhang;Wang Jin Song Yao;Rongfeng Huang;Thomas Laux;Xian Sheng Zhang
• 通讯作者: Xian Sheng Zhang