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PLoS One. 2009 Jul 30;4(7):e6442. doi: 10.1371/journal.pone.0006442.

AGO1 homeostasis involves differential production of 21-nt and 22-nt miR168 species by MIR168a and MIR168b.

Author information

1
Laboratoire de Biologie Cellulaire, Institut Jean-Pierre Bourgin, INRA, Versailles, France. herve.vaucheret@versailles.inra.fr

Abstract

BACKGROUND:

AGO1 associates with microRNAs (miRNAs) and regulates mRNAs through cleavage and translational repression. AGO1 homeostasis entails DCL1-dependent production of miR168 from MIR168a and MIR168b transcripts, post-transcriptional stabilization of miR168 by AGO1, and AGO1-catalyzed miR168-guided cleavage of AGO1 mRNA.

PRINCIPAL FINDINGS:

This study reveals that MIR168a is highly expressed and predominantly produces a 21-nt miR168 species. By contrast, MIR168b is expressed at low levels and produces an equal amount of 21- and 22-nt miR168 species. Only the 21-nt miR168 is preferentially stabilized by AGO1, and consequently, the accumulation of the 22-nt but not the 21-nt miR168 is reduced when DCL1 activity is impaired. mir168a mutants with strongly reduced levels of 21-nt miR168 are viable but exhibit developmental defects, particularly during environmentally challenging conditions.

CONCLUSIONS/SIGNIFICANCE:

These results suggest that 22-nt miR168 ensures basal cleavage of AGO1 mRNA whereas 21-nt miR168 permits an effective response to endogenous or environmental fluctuations owing to its preferential stabilization by AGO1.

PMID:
19649244
PMCID:
PMC2714465
DOI:
10.1371/journal.pone.0006442
[Indexed for MEDLINE]
Free PMC Article

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