Article

Dynamic isomiR regulation in Drosophila development.

Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, Australia.
RNA (impact factor: 5.09). 10/2010; 16(10):1881-8. DOI:10.1261/rna.2379610 pp.1881-8
Source: PubMed

ABSTRACT Several recent reports have demonstrated that microRNAs (miRNAs) can exhibit heterogeneous ends and post-transcriptional nontemplate 3' end additions of uridines or adenosines. Using two small RNA deep-sequencing data sets, we show here that these miRNA isoforms (isomiRs) are differentially expressed across Drosophila melanogaster development and tissues. Specifically, we demonstrate that: (1) nontemplate nucleotide additions of adenosines to miRNA 3' ends are highly abundant in early development; (2) a subset of miRNAs with nontemplate 3' Us are expressed in adult tissues; and (3) the size of at least eight "mature" (unmodified) miRNAs varies in a life-cycle or tissue-specific manner. These results suggest that subtle variability in isomiR expression, which is widely thought to be the result of inexact Dicer processing, is regulated and biologically meaningful. Indeed, a subset of the miRNAs enriched for 3' adenosine additions during early embryonic development, including miR-282 and miR-312, show enrichment for target sites in developmental genes that are expressed during late embryogenesis, suggesting that nontemplate additions increase miRNA stability or strengthen miRNA:target interactions. This work suggests that isomiR expression is an important aspect of miRNA biology, which warrants further investigation.

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Keywords

3' adenosine additions
 
adult tissues
 
embryogenesis
 
inexact Dicer processing
 
isomiR expression
 
isomiRs
 
life-cycle
 
microRNAs
 
miRNA biology
 
miRNA isoforms
 
miRNAs
 
miRNAs enriched
 
nontemplate 3'
 
nontemplate additions increase miRNA stability
 
post-transcriptional nontemplate 3' end additions
 
small RNA deep-sequencing data sets
 
subset
 
tissue-specific manner
 
uridines
 
warrants