Multiple targets of the microRNA miR-8 contribute to immune homeostasis in Drosophila.
MicroRNAs (miRNAs) are noncoding, around 22-nucleotide-long RNAs that exert significant modulatory roles in gene expression throughout the genome. As such, miRNAs take part in and modulate almost all biological processes like cell growth, development, and immunity. We previously showed that miR-8 miRNA plays a role in maintaining immune homeostasis in Drosophila. Here, we further discovered that targeting of multiple coding genes by miR-8 contributes to the maintenance of immune homeostasis. Toll and Dorsal, respectively the receptor and transcription factor in the Toll immune pathway, were found to be miR-8 targets, as shown by reporter assays and miR-8 null flies. Moreover, U-shaped (Ush), a previously verified miR-8 target, was seen to mediate miR-8 regulation of immune homeostasis. Consistently, overexpression of either Dorsal or Ush in the fat body led to increased Drosomycin expression, mimicking that induced by deletion of miR-8. Furthermore, mutation in Toll immune pathway or Ush rescues the abnormal expression of Drosomycin and lethality in miR-8 mutant. Thus, miR-8 regulates Drosophila immune homeostasis by targeting multiple immune genes, thereby contributing to survival.
Department of Life Science, Chung-Ang University, Seoul 156-756, Republic of Korea.
Gang Jun
GJ
Lee
Department of Life Science, Chung-Ang University, Seoul 156-756, Republic of Korea. Electronic address: sghyun@cau.ac.kr.
Seogang
S
Hyun
D000818:Animals; D029721:Drosophila Proteins / Q000276:immunology; D004331:Drosophila melanogaster / Q000235:genetics* / Q000276:immunology*; D007113:Immunity, Innate; D035683:MicroRNAs / Q000235:genetics*; D009687:Nuclear Proteins / Q000276:immunology; D010750:Phosphoproteins / Q000276:immunology; D051193:Toll-Like Receptors / Q000276:immunology; D014157:Transcription Factors / Q000276:immunology
D029721:Drosophila Proteins; D035683:MicroRNAs; D009687:Nuclear Proteins; D010750:Phosphoproteins; C068721:Tl protein, Drosophila; D051193:Toll-Like Receptors; D014157:Transcription Factors; C062236:dl protein, Drosophila; C526630:MIRN8 microRNA, Drosophila; C109258:ush protein, Drosophila; C091227:DRS protein, Drosophila
Dorsal; Drosophila; Immune homeostasis; Toll; U-shaped; miR-8