Wang Jin, Tian Caihuan, Zhang Cui, Shi Bihai, Cao Xiuwei, Zhang Tian-Qi, Zhao Zhong, Wang Jia-Wei, Jiao Yuling
State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, and National Center for Plant Gene Research, Beijing 100101, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Plant Cell. 2017 Jun;29(6):1373-1387. doi: 10.1105/tpc.16.00579. Epub 2017 Jun 2.
The homeodomain transcription factor WUSCHEL (WUS) defines the shoot stem cell niche, but the mechanisms underlying the establishment of expression remain unclear. Here, we show that cytokinin signaling precedes expression in leaf axils and activates expression de novo in the leaf axil to promote axillary meristem initiation. Furthermore, type-B Arabidopsis response regulator proteins, which are transcriptional activators in the cytokinin signaling pathway, directly bind to the promoter and activate its expression. Finally, we show that cytokinin activation of in the leaf axil correlates with increased histone acetylation and methylation markers associated with transcriptional activation, supporting the fact that expression requires a permissive epigenetic environment to restrict it to highly defined meristematic tissues. Taken together, these findings explain how cytokinin regulates axillary meristem initiation and establish a mechanistic framework for the postembryonic establishment of the shoot stem cell niche.
同源异型域转录因子WUSCHEL（WUS）定义了茎干细胞龛，但WUS表达建立的潜在机制仍不清楚。在这里，我们表明细胞分裂素信号传导在叶腋中WUS表达之前发生，并在叶腋中从头激活WUS表达以促进腋芽分生组织的起始。此外，拟南芥B型反应调节蛋白是细胞分裂素信号传导途径中的转录激活因子，直接结合WUS启动子并激活其表达。最后，我们表明叶腋中细胞分裂素对WUS的激活与转录激活相关的组蛋白乙酰化和甲基化标记增加相关，支持WUS表达需要允许的表观遗传环境以将其限制在高度特定的分生组织中的事实。综上所述，这些发现解释了细胞分裂素如何调节腋芽分生组织的起始，并为茎干细胞龛的胚后建立建立了一个机制框架。
