Zhou Yuyi, Honda Minami, Zhu Hongliang, Zhang Zhonghui, Guo Xinwei, Li Tianhong, Li Zhaohu, Peng Xu, Nakajima Keiji, Duan Liusheng, Zhang Xiuren
Cell Rep. 2015 Mar 24;10(11):1819-27. doi: 10.1016/j.celrep.2015.02.047.
Arabidopsis Argonaute10 (AGO10) specifically sequesters miR165 and miR166 and antagonizes their activity, thus regulating shoot apical meristem (SAM) development. However, where and when this sequestration acts is currently unclear. We show here that AGO10 represses miR165/166 activity in the embryo proper during early embryogenesis, through the apical and central regions of mature embryos, and eventually in the entire adaxial domain and vasculature of the cotyledons and leaf primordia. These locations are essentially identical to regions expressing PHABULOSA and REVOLUTA, mRNA targets of miR165/166. The Arabidopsis genome contains nine MIR165/166 genes. Sequestration of miR165/166 by the MIR165b, MIR166a, MIR166b, and MIR166g promoters efficiently rescues the SAM defect in ago10 mutants. Comparison of the expression patterns of AGO10 and the four MIR165/166 members suggests that AGO10 quenches the non-cell-autonomous activity of any miR165/166 that moves into AGO10-expressing niches. Thus, this study provides insight into how the spatiotemporal regulation of AGO10-miR165/166 activity affects SAM development.
拟南芥AGO10（AGO10）特异性地隔离miR165和miR166并拮抗其活性，从而调节茎尖分生组织（SAM）的发育。然而，目前尚不清楚这种隔离作用发生的位置和时间。我们在此表明，AGO10在胚胎发育早期通过成熟胚的顶端和中央区域，最终在子叶和叶原基的整个近轴区域和维管组织中抑制miR165/166在胚体中的活性。这些位置与miR165/166的mRNA靶标PHABULOSA和REVOLUTA的表达区域基本相同。拟南芥基因组包含9个MIR165/166基因。MIR165b、MIR166a、MIR166b和MIR166g启动子对miR165/166的隔离有效地挽救了ago10突变体中的SAM缺陷。AGO10与四个MIR165/166成员表达模式的比较表明，AGO10抑制了任何进入AGO10表达区域的miR165/166的非细胞自主性活性。因此，本研究为AGO10-miR165/166活性的时空调节如何影响SAM发育提供了见解。
