Arabidopsis Argonaute10 Specifically Sequesters miR166/165 to Regulate Shoot Apical Meristem Development

• Published in: Cell Vol. 145; no. 2; pp. 242 - 256
• Main Authors: Zhu, Hongliang, Hu, Fuqu, Wang, Ronghui, Zhou, Xin, Sze, Sing-Hoi, Liou, Lisa Wen, Barefoot, Ashley, Dickman, Martin, Zhang, Xiuren
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 15-04-2011
• Subjects: apical meristems; Arabidopsis; Arabidopsis - genetics; Arabidopsis - growth & development; Arabidopsis - metabolism; Arabidopsis Proteins - metabolism; Argonaute Proteins; binding capacity; catalytic activity; gene expression; Gene Expression Regulation, Plant; Meristem - growth & development; MicroRNAs - genetics; Plant Shoots; RNA, Plant - genetics; transcription factors
• ISSN: 0092-8674; 1097-4172
• DOI: 10.1016/j.cell.2011.03.024

The shoot apical meristem (SAM) comprises a group of undifferentiated cells that divide to maintain the plant meristem and also give rise to all shoot organs. SAM fate is specified by class III
HOMEODOMAIN-LEUCINE ZIPPER (
HD-ZIP III) transcription factors, which are targets of miR166/165. In
Arabidopsis,
AGO10 is a critical regulator of SAM maintenance, and here we demonstrate that AGO10 specifically interacts with miR166/165. The association is determined by a distinct structure of the miR166/165 duplex. Deficient loading of miR166 into AGO10 results in a defective SAM. Notably, the miRNA-binding ability of AGO10, but not its catalytic activity, is required for SAM development, and AGO10 has a higher binding affinity for miR166 than does AGO1, a principal contributor to miRNA-mediated silencing. We propose that AGO10 functions as a decoy for miR166/165 to maintain the SAM, preventing their incorporation into AGO1 complexes and the subsequent repression of
HD-ZIP III gene expression.
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Arabidopsis AGO10 predominantly associates with miR166/165 ► The duplex structure of miR166/165 determines their specific association with AGO10 ► AGO10 competes with AGO1 for miR166/165 binding ► The decoy activity of AGO10 drives shoot apical meristem development