Evolution and function of the extended miR-2 microRNA family

MicroRNAs are essential post-transcriptional regulators. Many animal microRNAs are clustered in the genome, and it has been shown that clustered microRNAs may be transcribed as a single transcript. Polycistronic microRNAs are often members of the same family, suggesting a role of tandem duplication...

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Bibliographic Details
Published in:RNA biology 2012-03, Vol.9 (3), p.242-248
Main Authors: Marco, Antonio, Hooks, Katarzyna, Griffiths-Jones, Sam
Format: Article
Language:English
Subjects:
Animals
Base Sequence
Binding
Biology
Bioscience
Calcium
Cancer
Cell
Conserved Sequence
Cycle
evolution
Evolution, Molecular
genomics
Humans
Landes
Life Sciences
MicroRNA family
microRNA targets
MicroRNAs - genetics
MicroRNAs - metabolism
miRNA
Molecular Sequence Annotation
Molecular Sequence Data
Multigene Family
Organogenesis
Phylogeny
polycistronic
Proteins
RNA Families
Sequence Alignment
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Summary:MicroRNAs are essential post-transcriptional regulators. Many animal microRNAs are clustered in the genome, and it has been shown that clustered microRNAs may be transcribed as a single transcript. Polycistronic microRNAs are often members of the same family, suggesting a role of tandem duplication in the emergence of clusters. The mir-2 microRNA family is the largest in Drosophila melanogaster, with 8 members that are mostly clustered in the genome. Previous studies suggest that the copy number and genomic distribution of mir-2 family members has been subject to significant change during evolution. The effects of such changes on their function are still unknown. Here we study the evolution of function in the mir-2 family. Our analyses show that, in spite of the change in number and organization among invertebrates, most mir-2 loci produce very similar mature microRNA products. Multiple mature miR-2 sequences are predicted to target genes involved in neural development in Drosophila. These targeting properties are conserved in the distant species Caenorhabditis elegans. Duplication followed by functional diversification is frequent during protein-coding gene evolution. However, our results suggest that the production of microRNA clusters by gene duplication rarely involves functional changes. This pattern of functional redundancy among clustered paralogous microRNAs reflects birth-and-death evolutionary dynamics. However, we identified a small number of mir-2 sequences in Drosophila that may have undergone functional shifts associated with genomic rearrangements. Therefore, redundancy in microRNA families may facilitate the acquisition of novel functional features.
ISSN:1547-6286
1555-8584
DOI:10.4161/rna.19160