title: Drosophila microRNA-34 Impairs Axon Pruning of Mushroom Body γ Neurons by Downregulating the Expression of Ecdysone Receptor.
abstract: MicroRNA-34 (miR-34) is crucial for preventing chronic large-scale neurite degeneration in the aged brain of Drosophila melanogaster. Here we investigated the role of miR-34 in two other types of large-scale axon degeneration in Drosophila: axotomy-induced axon degeneration in olfactory sensory neurons (OSNs) and developmentally related axon pruning in mushroom body (MB) neurons. Ectopically overexpressed miR-34 did not inhibit axon degeneration in OSNs following axotomy, whereas ectopically overexpressed miR-34 in differentiated MB neurons impaired γ axon pruning. Intriguingly, the miR-34-induced γ axon pruning defect resulted from downregulating the expression of ecdysone receptor B1 (EcR-B1) in differentiated MB γ neurons. Notably, the separate overexpression of EcR-B1 or a transforming growth factor- β receptor Baboon, whose activation can upregulate the EcR-B1 expression, in MB neurons rescued the miR-34-induced γ axon pruning phenotype. Future investigations of miR-34 targets that regulate the expression of EcR-B1 in MB γ neurons are warranted to elucidate pathways that regulate axon pruning, and to provide insight into mechanisms that control large-scale axon degeneration in the nervous system.
authors.affiliation: Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan.|Institute of Molecular and Genomic Medicine, National Health Research Institutes, Miaoli County, Taiwan.|Institute of Molecular and Cellular Biology, College of Life Science, National Taiwan University, Taipei, Taiwan.
authors.forename: Yen-Wei
authors.initials: YW
authors.lastname: Lai
authors.affiliation: Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan.
authors.forename: Sao-Yu
authors.initials: SY
authors.lastname: Chu
authors.affiliation: Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan.
authors.forename: Jia-Yi
authors.initials: JY
authors.lastname: Wei
authors.affiliation: Institute of Molecular and Genomic Medicine, National Health Research Institutes, Miaoli County, Taiwan.
authors.forename: Chu-Ya
authors.initials: CY
authors.lastname: Cheng
authors.affiliation: Institute of Molecular and Genomic Medicine, National Health Research Institutes, Miaoli County, Taiwan.
authors.forename: Jian-Chiuan
authors.initials: JC
authors.lastname: Li
authors.affiliation: Institute of Molecular and Genomic Medicine, National Health Research Institutes, Miaoli County, Taiwan.|Institute of Molecular and Cellular Biology, College of Life Science, National Taiwan University, Taipei, Taiwan.
authors.forename: Po-Lin
authors.initials: PL
authors.lastname: Chen
authors.affiliation: Institute of Molecular and Genomic Medicine, National Health Research Institutes, Miaoli County, Taiwan.|Institute of Molecular and Cellular Biology, College of Life Science, National Taiwan University, Taipei, Taiwan.
authors.forename: Chun-Hong
authors.initials: CH
authors.lastname: Chen
authors.affiliation: Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan.
authors.forename: Hung-Hsiang
authors.initials: HH
authors.lastname: Yu
mesh_terms: D000818:Animals; D019771:Axotomy; D002454:Cell Differentiation; D015536:Down-Regulation; D004331:Drosophila melanogaster / Q000235:genetics / Q000254:growth & development*; D018507:Gene Expression Regulation, Developmental; D035683:MicroRNAs / Q000235:genetics*; D024521:Mushroom Bodies / Q000166:cytology* / Q000254:growth & development; D009473:Neuronal Plasticity; D018034:Olfactory Receptor Neurons / Q000166:cytology; D011987:Receptors, Steroid / Q000378:metabolism*
chemical_list: C570893:MIRN34 microRNA, Drosophila; D035683:MicroRNAs; D011987:Receptors, Steroid; C055469:ecdysone receptor