A Global View of Regenerating Plant Cells

描述（由申请人提供）：多细胞生命的所有主要分支都有修复受损组织的能力，使用来自成人身体的细胞产生替代细胞来补充组织和器官修复。最近对哺乳动物的研究表明，从一种组织中产生的成体干细胞可能具有灵活性，可以产生另一种组织的特化细胞，这提高了成体干细胞可能为再生受损组织提供治疗的可能性。植物和动物共享许多基本的细胞过程，包括RNA干扰，这是一种原始的防御系统，也控制着两个王国的发育。植物是再生的典型模型，因为几乎所有的植物物种都很容易使用为一种目的而保留的细胞来取代另一种目的的受损细胞，类似于哺乳动物成体干细胞的灵活性（“发育可塑性”）。我们使用植物体内再生系统，提供强大的分析工具，以帮助了解模式植物拟南芥细胞命运可塑性的过程。我们提出了一个假设，即部分分化的细胞首先必须恢复到更基本的干细胞命运，可能类似于胚胎干细胞，以便在再生过程中产生新的细胞类型。此外，我们使用基因组学来发现可能在细胞水平上触发再生的候选物质。在实验方面，我们使用具有简单而高度组织化结构的根尖和大量荧光标记来分析再生组织中细胞中发生的分子事件。在Aim 1中，我们使用高分辨率显微镜观察单个细胞，监测它们的身份和它们向干细胞的潜在逆转，以确定细胞如何改变其身份。在Aim 2中，我们测量了各种不同干细胞中的基因活性，以获得干细胞身份的全面目录。这是使用我们开发的新技术来捕获特定的细胞类型，并使用微阵列监测其综合基因活性。在目标3中，我们使用相同的方法获得再生细胞的全面读数。然后，我们使用Aim 2中鉴定的干细胞识别基因目录来询问再生细胞是否具有与基底干细胞的任何共同因素。在Aim 4中，我们着眼于基因中的突变，其表达与早期再生有关。这项工作的目的是了解在细胞水平上触发组织再生的基本机制。这些结果旨在深入了解植物再生的基本机制，这些机制可能与植物中潜在的类似机制有关，无论是在共同基因水平上还是在控制类似过程的不同基因水平上。

DESCRIPTION (provided by applicant): All major branches of multi-cellular life have the ability to repair damaged tissue, using cells from the adult body to generate replacement cells for tissue replenishment and organ repair. Recent work in mammals has suggested that adult stem cells arising from one tissue may have the flexibility to give rise to specialized cells of another tissue, raising the possibility that adult stem cells may provide a therapy to regenerate damaged tissue. Plants and animals share many basic cellular processes, including RNA interference, a primitive defense system that has also controls development in both kingdoms. Plants are a quintessential model for regeneration, as almost all plant species readily use cells set aside for one purpose to replace damaged cells of another purpose, analogously to adult stem cell flexibility in mammals ("developmental plasticity"). We use an in vivo regeneration system in plants that affords powerful analytical tools to help understand the process of cell fate plasticity in the model plant Arabidopsis thaliana. We address the hypothesis that partially differentiated cells first must revert to more basic stem cell fates perhaps similar to embryonic stem cells, in order to give rise to new cell types during regeneration. In addition, we use genomics to discover the candidate that may trigger regeneration at the cellular level. On the experimental side, we use the root tip, which has a simple and highly organized structure, and a large selection of fluorescent markers to analyze the molecular events that occur in cells in regenerating tissue. In Aim 1, we use high-resolution microscopy to visualize individual cells, monitor their identities and their potential reversion to stem cells in order to determine how cells can transform their identity. In Aim 2, we measure gene activity in a variety of different stem cells to obtain a comprehensive catalog of stem cell identity. This is done using new techniques we have developed to capture specific cell types and monitor their comprehensive gene activity using microarrays. In Aim 3, we use the same methods to obtain comprehensive readouts of the cells that undergo regeneration. We then use the catalog of stem cell identity genes identified in Aim 2 to ask whether regenerating cells possess any common factors with basal stem cells. In Aim 4, we look at mutants in genes whose expression implicates them in early regeneration. This work is aimed at understanding the fundamental mechanisms that trigger tissue regeneration at the level of the cell. These results are aimed at providing insights into the fundamental mechanisms of regeneration in plants that can be related to potentially similar mechanisms in plants either at the level of common genes or different genes that control analogous processes.