title: Conserved microRNA miR-8 controls body size in response to steroid signaling in Drosophila.
abstract: Body size determination is a process that is tightly linked with developmental maturation. Ecdysone, an insect maturation hormone, contributes to this process by antagonizing insulin signaling and thereby suppressing juvenile growth. Here, we report that the microRNA miR-8 and its target, u-shaped (USH), a conserved microRNA/target axis that regulates insulin signaling, are critical for ecdysone-induced body size determination in Drosophila. We found that the miR-8 level is reduced in response to ecdysone, while the USH level is up-regulated reciprocally, and that miR-8 is transcriptionally repressed by ecdysone's early response genes. Furthermore, modulating the miR-8 level correlatively changes the fly body size; either overexpression or deletion of miR-8 abrogates ecdysone-induced growth control. Consistently, perturbation of USH impedes ecdysone's effect on body growth. Thus, miR-8 acts as a molecular rheostat that tunes organismal growth in response to a developmental maturation signal.
authors: School of Biological Sciences, Seoul National University, Seoul 151-742, Korea.
authors: Hua
authors: H
authors: Jin
authors: School of Biological Sciences, Seoul National University, Seoul 151-742, Korea.
authors: V Narry
authors: VN
authors: Kim
authors: School of Biological Sciences, Seoul National University, Seoul 151-742, Korea.|School of Biological Sciences, Chung-Ang University, Seoul 156-756, Korea
authors: Seogang
authors: S
authors: Hyun
mesh_terms: D000818:Animals; D002460:Cell Line; D004331:Drosophila melanogaster / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D004440:Ecdysone / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D035683:MicroRNAs / Q000235:genetics*; D015398:Signal Transduction; D015854:Up-Regulation
chemical_list: D035683:MicroRNAs; C526630:MIRN8 microRNA, Drosophila; D004440:Ecdysone