title: Structure, evolution and function of the bi-directionally transcribed iab-4/iab-8 microRNA locus in arthropods.
abstract: In Drosophila melanogaster, the iab-4/iab-8 locus encodes bi-directionally transcribed microRNAs that regulate the function of flanking Hox transcription factors. We show that bi-directional transcription, temporal and spatial expression patterns and Hox regulatory function of the iab-4/iab-8 locus are conserved between fly and the beetle Tribolium castaneum. Computational predictions suggest iab-4 and iab-8 microRNAs can target common sites, and cell-culture assays confirm that iab-4 and iab-8 function overlaps on Hox target sites in both fly and beetle. However, we observe key differences in the way Hox genes are targeted. For instance, abd-A transcripts are targeted only by iab-8 in Drosophila, whereas both iab-4 and iab-8 bind to Tribolium abd-A. Our evolutionary and functional characterization of a bi-directionally transcribed microRNA establishes the iab-4/iab-8 system as a model for understanding how multiple products from sense and antisense microRNAs target common sites.
authors: School of Life Sciences, Chinese University of Hong Kong, Shatin, Hong Kong, China.
authors: Jerome H L
authors: JH
authors: Hui
authors: Antonio
authors: A
authors: Marco
authors: Suzanne
authors: S
authors: Hunt
authors: Janet
authors: J
authors: Melling
authors: Sam
authors: S
authors: Griffiths-Jones
authors: Matthew
authors: M
authors: Ronshaugen
mesh_terms: D000818:Animals; D002460:Cell Line; D002874:Chromosome Mapping; D004331:Drosophila melanogaster / Q000235:genetics*; D019143:Evolution, Molecular; D018507:Gene Expression Regulation, Developmental; D005801:Genes, Homeobox; D017344:Genes, Insect; D056426:Genetic Loci; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D010802:Phylogeny; D034622:RNA Interference; D014158:Transcription, Genetic; D014231:Tribolium / Q000235:genetics*
chemical_list: D035683:MicroRNAs; C580822:iab-4 microRNA, Drosophila; C580823:iab-8 microRNA, Drosophila