AGO1 homeostasis involves differential production of 21-nt and 22-nt miR168 species by MIR168a and MIR168b.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 19649244.
- Also identified by DOI 10.1371/journal.pone.0006442 and PMC identifier 2714465.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
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.
Medical subject headings
- Arabidopsis
- Arabidopsis Proteins
- Homeostasis
- MicroRNAs