A model of repair: intercellular signaling and self-organization in plant regeneration

项目摘要 植物具有在受伤后再生成年身体部位的特殊能力， 器官替代的概念模型。他们甚至可以迅速改革他们的成人干细胞壁龛后， 完全切除我的实验室开创了研究植物再生的新系统和新技术。我们 开发了使用转录组学和活体成像跟踪重编程细胞的细胞身份的方法 再生过程中的技术在这项工作中，我带头努力引进新的 将单细胞RNA-seq等技术应用于植物研究。使用这些和其他技术开发 在NIGMS R 01 GM 078279下，我们发现再生根似乎重演了胚胎程序 在器官再生过程中。这项工作使我们提出了这种高度自组织的模型， 系统协调整个器官及其干细胞生态位的再生。虽然新工具 就像单细胞RNA-seq一样，它提供了一个细胞一个细胞地剖析发育程序的强大方法， 它们在很大程度上对细胞间通讯在介导组织组装中的作用保持沉默。所以我们 目前的工作重点是制定新的办法来弥补这一差距。在一个提议的系统中，我们 以细胞类型特异性方式诱导阻断共形（直接）通信通道， 细胞RNA-seq来测试正常胚胎后发育过程中对邻近和远处组织的影响， 器官发生和再生（Block-Seq）。这类似于观察来自 一个小区发送给所有的邻居，而不是信号本身。植物中一种常见的信号传导模式是 转录因子从一个细胞到其邻近细胞的蛋白质水平移动。来追踪蛋白质的运动 综合而言，我们正在开发一种点击化学方法，将标记的氨基酸掺入 特定细胞类型，随后捕获并质谱分析相邻细胞中的移动的蛋白 Mobilome（移动）这种方法旨在揭示植物细胞用来 组织发展。总的来说，这些方法的动机是一个基本问题， 医学相关问题：位置信号如何产生一套规则， 器官的再生重建

PROJECT SUMMARY Plants have exceptional capacity to regenerate adult body parts after injury, providing an excellent conceptual model for organ replacement. They can even rapidly reform their adult stem cell niches after complete excision. My lab has pioneered new systems and techniques to study plant regeneration. We developed methods for tracking cell identity of reprogramming cells using transcriptomic and live imaging techniques during regeneration. In connection with this work, I have led efforts to introduce new technologies like single-cell RNA-seq into plant research. Using these and other techniques developed under NIGMS R01GM078279, we found that regenerating roots appear to recapitulate embryonic programs during organ regeneration. The work has led to us to propose models of how this highly self-organizing system orchestrates the regeneration of an entire organ and its stem cell niche. However, while new tools like in single-cell RNA-seq provide powerful approaches to dissect developmental programs cell-by-cell, they are largely silent on the role of cell-cell communication in mediating tissue assembly. Hence, our current efforts are focused on developing new approaches to address this gap. In one proposed system, we inducibly block symplastic (direct) communication channels in a cell type-specific manner and use single- cell RNA-seq to test the consequences on neighboring and distant tissues during normal post-embryonic organogenesis and regeneration (Block-Seq). This is akin to observing the consequences of signaling from one cell to all its neighbors but not the signals themselves. One common mode of signaling in plants is the protein-level movement of transcription factors from one cell to its neighbors. To track protein movement comprehensively, we are developing a click chemistry approach to incorporate labeled amino acids in specific cell types followed by capture and mass spectrometry of the mobile proteins in neighboring cell types (the Mobilome). This approach is designed to reveal many of the signals that plant cells use to organize development. Overall, these approaches are motivated by a basic question that underpins a medically relevant question: how do positional signals generate a set of rules that allow the flawless reconstruction of organs in regeneration?