AGO1 homeostasis entails coexpression of MIR168 and AGO1 and preferential stabilization of miR168 by AGO1.
Arabidopsis ARGONAUTE1 (AGO1) encodes the RNA slicer enzyme of the microRNA (miRNA) pathway and is regulated by miR168-programmed, AGO1-catalyzed mRNA cleavage. Here, we describe two additional regulatory processes required for AGO1 homeostasis: transcriptional coregulation of MIR168 and AGO1 genes, and posttranscriptional stabilization of miR168 by AGO1. Disrupting any of these regulatory processes by using mutations or transgenes disturbs a proper functioning of the miRNA pathway. In contrast, minor perturbation leads to fine-tuned posttranscriptional adjustment of miR168 and AGO1 levels, thereby maintaining a proper balance of other miRNAs, which, together with AGO1, control the mRNA levels of miRNA targets. We suggest that miR168 stabilization occurs at the level of silencing-complex assembly and that modulating the efficiency of assembling miRNA-programmed silencing complexes will also be important in other contexts.
Vaucheret
Hervé
H
Laboratoire de Biologie Cellulaire, Institut Jean-Pierre Bourgin, INRA, 78026 Versailles Cedex, France. herve.vaucheret@versailles.inra.fr
Mallory
Allison C
AC
Bartel
David P
DP
D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D060565:Argonaute Proteins; D018797:Cell Cycle Proteins / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D006706:Homeostasis; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D010641:Phenotype; D030821:Plants, Genetically Modified; D012323:RNA Processing, Post-Transcriptional; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D018749:RNA, Plant / Q000235:genetics*; D034743:RNA-Induced Silencing Complex; D043244:Ribonuclease III / Q000378:metabolism; D019076:Transgenes / Q000502:physiology
C117457:AGO1 protein, Arabidopsis; D029681:Arabidopsis Proteins; D060565:Argonaute Proteins; D018797:Cell Cycle Proteins; D035683:MicroRNAs; D012333:RNA, Messenger; D018749:RNA, Plant; D034743:RNA-Induced Silencing Complex; C402383:DCL1 protein, Arabidopsis; D043244:Ribonuclease III