Display Settings:

Format

Send to:

Choose Destination
See comment in PubMed Commons below
Proc Natl Acad Sci U S A. 2008 Jul 1;105(26):8994-9. doi: 10.1073/pnas.0803218105. Epub 2008 Jun 25.

Structurally different alleles of the ath-MIR824 microRNA precursor are maintained at high frequency in Arabidopsis thaliana.

Author information

  • 1Max Planck Institute for Plant Breeding Research, Carl-von-LinnĂ© Weg 10, 50829 Cologne, Germany.

Abstract

In plants and animals, gene expression can be down-regulated at the posttranscriptional level by microRNAs (miRNAs), a class of small endogenous RNA. Comparative analysis of miRNA content across species indicates continuous birth and death of these loci in the course of evolution. However, little is known about the microevolutionary dynamics of these genetic elements, especially in plants. In this article we examine polymorphism at two miRNA-encoding loci in Arabidopsis thaliana, miR856 and miR824, which are not found in rice or poplar. We compare their diversity to other miRNA-encoding loci conserved across distant taxa. We find that levels of variation vary significantly across loci and that the two recently derived loci harbor patterns of diversity deviating from neutrality. miRNA miR856 shows a weak signature of a selective sweep whereas miR824 displays signs of balancing selection. A detailed examination of structural variation among alleles found at the miR824-encoding locus suggests nonrandom evolution of a thermoresistant substructure in the precursor. Expression analysis of pre-miR824 and its target, AGL16, indicates that these structural differences likely impact the processing of mature miR824. Our work highlights the relevance of RNA structure in precursor sequence evolution, suggesting that the evolutionary dynamics of miRNA-encoding loci is more complex than suggested by the constraints exerted on the interaction between mature miRNA fragments and their target exon.

PMID:
18579782
[PubMed - indexed for MEDLINE]
PMCID:
PMC2440359
Free PMC Article

Images from this publication.See all images (3)Free text

Fig. 1.
Fig. 2.
Fig. 3.

Publication Types, MeSH Terms, Substances, Secondary Source ID

Publication Types

MeSH Terms

Substances

Secondary Source ID

PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Write to the Help Desk