Loss of miR-210 leads to progressive retinal degeneration in Drosophila melanogaster

miRNAs are small, non-coding RNAs that regulate gene expression post-transcriptionally. We used small RNA sequencing to identify tissue-specific miRNAs in the adult brain, thorax, gut and fat body of Drosophila melanogaster. One of the most brain-specific miRNAs that we identified was miR-210, an evolutionarily highly conserved miRNA implicated in the regulation of hypoxia in mammals. In Drosophila, we show that miR-210 is specifically expressed in sensory organs including photoreceptors. miR-210 knock-out mutants are not sensitive towards hypoxia but show progressive degradation of photoreceptor cells, accompanied by decreased photoreceptor potential, demonstrating an important function of miR-210 in photoreceptor maintenance and survival. Multi-tissue miRNA-seq in wild type D. melanogaster to identify tissue-specific miRNAs. RNA-seq of miR-210 knockout fly heads to identify potential targets.