MiR-2 family regulates insect metamorphosis by controlling the juvenile hormone signaling pathway.
In 2009 we reported that depletion of Dicer-1, the enzyme that catalyzes the final step of miRNA biosynthesis, prevents metamorphosis in Blattella germanica. However, the precise regulatory roles of miRNAs in the process have remained elusive. In the present work, we have observed that Dicer-1 depletion results in an increase of mRNA levels of Krüppel homolog 1 (Kr-h1), a juvenile hormone-dependent transcription factor that represses metamorphosis, and that depletion of Kr-h1 expression in Dicer-1 knockdown individuals rescues metamorphosis. We have also found that the 3'UTR of Kr-h1 mRNA contains a functional binding site for miR-2 family miRNAs (for miR-2, miR-13a, and miR-13b). These data suggest that metamorphosis impairment caused by Dicer-1 and miRNA depletion is due to a deregulation of Kr-h1 expression and that this deregulation is derived from a deficiency of miR-2 miRNAs. We corroborated this by treating the last nymphal instar of B. germanica with an miR-2 inhibitor, which impaired metamorphosis, and by treating Dicer-1-depleted individuals with an miR-2 mimic to allow nymphal-to-adult metamorphosis to proceed. Taken together, the data indicate that miR-2 miRNAs scavenge Kr-h1 transcripts when the transition from nymph to adult should be taking place, thus crucially contributing to the correct culmination of metamorphosis.
['Lozano|Jesus|J|http://orcid.org/0000-0003-3597-1221', 'Montañez|Raúl|R|http://orcid.org/0000-0003-1667-2218', 'Belles|Xavier|X|']
D000465:Algorithms D000818:Animals D001665:Binding Sites D018076:DNA, Complementary D004330:Drosophila D029721:Drosophila Proteins D005260:Female D018507:Gene Expression Regulation, Developmental D019476:Insect Proteins D007313:Insecta D007605:Juvenile Hormones D008675:Metamorphosis, Biological D035683:MicroRNAs D010641:Phenotype D020365:RNA Helicases D043244:Ribonuclease III D015398:Signal Transduction D013696:Temperature
insect metamorphosis juvenile hormone evolution of metamorphosis insect hormones microRNA