Irreversible fate commitment in the Arabidopsis stomatal lineage requires a FAMA and RETINOBLASTOMA-RELATED module.
Irreversible fate commitment in the Arabidopsis stomatal lineage requires a FAMA and RETINOBLASTOMA-RELATED module.
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DOI：
10.7554/elife.03271
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发表时间：
2014-10-10
期刊：
影响因子：
7.7
通讯作者：
Bergmann DC
中科院分区：
文献类型：
--
作者：
Matos JL;Lau OS;Hachez C;Cruz-Ramírez A;Scheres B;Bergmann DC
假定植物细胞的全能性导致了关于如何建立特定干细胞谱系和最终命运的问题。在拟南芥气孔谱系中，一个短暂的自我更新阶段产生分化成两种表皮细胞类型之一的前体细胞，保卫细胞或铺面细胞。我们发现，不可逆的分化的保卫细胞涉及视网膜母细胞瘤相关（RBR）招聘到调控区域的主调节气孔启动，促进通过相互作用与终端气孔谱系转录因子，法马。破坏法马和RBR之间的物理相互作用优先揭示了RBR在执行命运承诺的作用，在这种发展背景下，其在细胞周期控制中的作用。与法马和RBR调节相关的表型分析揭示了迭代分裂和终末分化在植物干细胞谱系中协调调节的方式。DOI：http://dx.doi.org/10.7554/eLife.03271.001动物和植物中的干细胞通过分裂和成为特殊类型的细胞来帮助制造和补充身体的组织。一旦专门用于某种功能，重要的是细胞保持该功能。在植物叶片中，一种类型的干细胞产生两种不同类型的特化细胞：铺路细胞和气孔保卫细胞。铺路细胞锁在一起，形成一个防水屏障，而保卫细胞包围着小孔，这些小孔打开和关闭，使植物与大气交换水，氧气和二氧化碳。一旦一个细胞成为一个铺路细胞或警卫细胞，它就不会再改变它的身份。然而，如果从植物中取出一个细胞，它可以恢复为干细胞，并可以从中生长出一个全新的植物。这就提出了一个问题，即在完整的植物中，如何防止像铺路细胞和保卫细胞这样的特化细胞恢复为干细胞。在广泛用作研究模式生物的小型开花植物拟南芥中，一种名为法马的蛋白质负责控制一组将干细胞转化为保卫细胞的基因。Matos等人现在发现法马需要与另一种称为RBR的蛋白质结合来控制这一过程。这两种蛋白质似乎通过改变控制干细胞基因区域的DNA结构，使干细胞向保卫细胞的转变永久化。RBR类似于一种名为视网膜母细胞瘤的人类蛋白质，有助于预防肿瘤和调节干细胞，但它如何在人类中发挥这些功能仍存在争议。由于干细胞和保卫细胞都显示在植物叶片的表面，并留下了它们过去的线索，马托斯等人能够观察到干细胞成长为成熟的保卫细胞。当法马和RBR之间的合作关系被打破时，有可能看到这些相同的保卫细胞恢复为干细胞。看到发展的“倒退”可以提供有用的见解细胞身份是如何控制在植物和动物。DOI：http://dx.doi.org/10.7554/eLife.03271.002网站
The presumed totipotency of plant cells leads to questions about how specific stem cell lineages and terminal fates could be established. In the Arabidopsis stomatal lineage, a transient self-renewing phase creates precursors that differentiate into one of two epidermal cell types, guard cells or pavement cells. We found that irreversible differentiation of guard cells involves RETINOBLASTOMA-RELATED (RBR) recruitment to regulatory regions of master regulators of stomatal initiation, facilitated through interaction with a terminal stomatal lineage transcription factor, FAMA. Disrupting physical interactions between FAMA and RBR preferentially reveals the role of RBR in enforcing fate commitment over its role in cell-cycle control in this developmental context. Analysis of the phenotypes linked to the modulation of FAMA and RBR sheds new light on the way iterative divisions and terminal differentiation are coordinately regulated in a plant stem-cell lineage. DOI: http://dx.doi.org/10.7554/eLife.03271.001 Stem cells in animals and plants help to make and replenish the tissues of the body by dividing and becoming specialized types of cells. Once specialized for a certain function, it is important that a cell keeps that function. In plant leaves, one type of stem cell makes two different types of specialized cells: pavement cells and stomatal guard cells. Pavement cells lock together to form a waterproof barrier to the outside, while guard cells surround the small pores that open and close to allow the plant to exchange water, oxygen and carbon dioxide with the atmosphere. Once a cell becomes a pavement cell or a guard cell, it does not change its identity again. However, if a single cell is removed from a plant, it can revert to a stem cell and a whole new plant can be grown from it. This poses the question of how, in intact plants, specialized cells like pavement cells and guard cells are prevented from reverting to stem cells. In Arabidopsis thaliana, a small flowering plant that is widely used as a model organism in research, a protein called FAMA is responsible for controlling a set of genes that turn stem cells into guard cells. Matos et al. have now found that FAMA needs to bind to another protein called RBR to control this process. It seems that these two proteins make the transition from stem cell to guard cell permanent by changing the structure of DNA in regions that control stem cell genes. RBR is similar to a human protein called Retinoblastoma that helps prevent tumors and regulate stem cells, but how it actually performs these functions in humans is still debated. Because stem cells and guard cells are displayed on the surface of plant leaves and leave behind clues of their past, Matos et al. were able to watch stem cells grow up to be mature guard cells. When the partnership between FAMA and RBR was broken, it was possible to watch those same guard cells revert backwards into stem cells. Seeing development ‘rewind’ could provide useful insights into the way in which cell identity is controlled in both plants and animals. DOI: http://dx.doi.org/10.7554/eLife.03271.002