Arabidopsis Argonaute10 specifically sequesters miR166/165 to regulate shoot apical meristem development

Cell. 2011 Apr 15;145(2):242-56. 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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Arabidopsis / genetics
  • Arabidopsis / growth & development*
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / metabolism*
  • Argonaute Proteins
  • Gene Expression Regulation, Plant*
  • Meristem / growth & development*
  • MicroRNAs / genetics*
  • Plant Shoots
  • RNA, Plant / genetics*


  • AGO10 protein, Arabidopsis
  • Arabidopsis Proteins
  • Argonaute Proteins
  • MicroRNAs
  • RNA, Plant