A mechanistic framework for noncell autonomous stem cell induction in Arabidopsis
A mechanistic framework for noncell autonomous stem cell induction in Arabidopsis
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DOI：
10.1073/pnas.1406446111
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发表时间：
2014-10-07
影响因子：
11.1
通讯作者：
Lohmann, Jan U.
中科院分区：
文献类型：
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作者：
Daum, Gabor;Medzihradszky, Anna;Lohmann, Jan U.
细胞间的通讯对于多细胞的发育是必不可少的，因此，进化带来了一系列不同的机制来实现这一目的。一致地，通过非细胞自主信号诱导和维持干细胞命运是许多生物体共有的特征，并且可能取决于分泌因子、直接细胞-细胞接触、基质相互作用或这些机制的组合。虽然许多基本的细胞过程在动物和植物之间都很保守，但细胞间信号传递是两个生命王国之间出现实质性差异的一种功能。最显著的差异之一是细胞质桥的存在，称为胞间连丝，它促进了相邻植物细胞之间的分子交换，并为植物谱系中的细胞间通讯提供了独特的途径。在这里，我们提供的证据表明，干细胞诱导转录因子WUSCHEL（WUS），在龛中表达，移动到干细胞通过胞间连丝在一个高度调节的方式，这种运动是必需的WUS功能，因此，在拟南芥干细胞活性。我们发现，细胞上下文无关的流动性编码的WUS蛋白质序列和介导的多个域。最后，我们证明了WUS同源二聚化所需的限制运动的蛋白质的部分，这表明WUS二聚体的形成可能有助于调节顶端干细胞的活性。
Cell-cell communication is essential for multicellular development and, consequently, evolution has brought about an array of distinct mechanisms serving this purpose. Consistently, induction and maintenance of stem cell fate by noncell autonomous signals is a feature shared by many organisms and may depend on secreted factors, direct cell-cell contact, matrix interactions, or a combination of these mechanisms. Although many basic cellular processes are well conserved between animals and plants, cell-to-cell signaling is one function where substantial diversity has arisen between the two kingdoms of life. One of the most striking differences is the presence of cytoplasmic bridges, called plasmodesmata, which facilitate the exchange of molecules between neighboring plant cells and provide a unique route for cell-cell communication in the plant lineage. Here, we provide evidence that the stem cell inducing transcription factor WUSCHEL (WUS), expressed in the niche, moves to the stem cells via plasmodesmata in a highly regulated fashion and that this movement is required for WUS function and, thus, stem cell activity in Arabidopsis thaliana. We show that cell context-independent mobility is encoded in the WUS protein sequence and mediated by multiple domains. Finally, we demonstrate that parts of the protein that restrict movement are required for WUS homodimerization, suggesting that formation of WUS dimers might contribute to the regulation of apical stem cell activity.