Nature：植物根和茎中干细胞体系之间的联系
植物有两个明显不同的干细胞体系，分别在根分裂组织和茎分裂组织中，它们不断分裂而产生新的组织和器官。以前的研究工作发现，在两个体系中有不同的发育模式和不同的控制基因，但Sarkar等人现在发现，二者之间在机理上有一个强烈的联系。两个体系的信号作用中心都利用相关的转录因子(茎中为WUSCHEL，根中为WOX5)来使相邻的干细胞保持不分化，这两个因子在两个分裂组织中都发挥作用，以维持正常功能。这一发现提供的分子证据表明，干细胞调控系统起源于根和茎在作为现代高等植物祖先的陆地植物中分开之前。
Letter
Nature 446, 811-814 (12 April 2007) | doi:10.1038/nature05703; Received 9 January 2007; Accepted 23 February 2007
Conserved factors regulate signalling in Arabidopsis thaliana shoot and root stem cell organizers
Ananda K. Sarkar1,4,5, Marijn Luijten2,4, Shunsuke Miyashima3, Michael Lenhard1,5, Takashi Hashimoto3, Keiji Nakajima3, Ben Scheres2, Renze Heidstra2 & Thomas Laux1
- Institute of Biology III, University of Freiburg, Schänzlestra
e 1, 79104 Freiburg, Germany
- Department of Molecular Cell Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan
- These authors contributed equally to this work.
- Present addresses: Cold Spring Harbor Laboratory, One Bungtown Road, Cold Spring Harbor, New York 11724, USA (A.K.S.); John Innes Centre, Colney Lane, Norwich, N4 7UH, UK (M.K.).
Correspondence to: Thomas Laux1 Correspondence and requests for materials should be addressed to T.L. (Email: laux@biologie.uni-freiburg.de).
Throughout the lifespan of a plant, which in some cases can last more than one thousand years, the stem cell niches in the root and shoot apical meristems provide cells for the formation of complete root and shoot systems, respectively. Both niches are superficially different and it has remained unclear whether common regulatory mechanisms exist. Here we address whether root and shoot meristems use related factors for stem cell maintenance. In the root niche the quiescent centre cells, surrounded by the stem cells, express the homeobox gene WOX5 (WUSCHEL-RELATED HOMEOBOX 5)1, a homologue of the WUSCHEL (WUS) gene that non-cell-autonomously maintains stem cells in the shoot meristem2. Loss of WOX5 function in the root meristem stem cell niche causes terminal differentiation in distal stem cells and, redundantly with other regulators, also provokes differentiation of the proximal meristem. Conversely, gain of WOX5 function blocks differentiation of distal stem cell descendents that normally differentiate. Importantly, both WOX5 and WUS maintain stem cells in either a root or shoot context. Together, our data indicate that stem cell maintenance signalling in both meristems employs related regulators.
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