Identification of miR ‐305, a microRNA that promotes aging, and its target mRNAs in Drosophila

MicroRNAs (miRNAs) are involved in the regulation of important biological processes. Here, we describe a novel Drosophila miRNAs involved in aging. We selected eight Drosophila miRNAs, displaying high homology with seed sequences of aging‐related miRNAs characterized in other species, and investigated whether the over‐expression of these miRNAs affected aging in Drosophila adult flies. The lifespan of adults over‐expressing miR‐305, a miRNA showing high homology with miR‐239 in C. elegans, was significantly shorter. Conversely, a reduction in miR‐305 expression led to a longer lifespan than that in control flies. miR‐305 over‐expression accelerated the impairment of locomotor activity and promoted the age‐dependent accumulation of poly‐ubiquitinated protein aggregates in the muscle, as flies aged. Thus, we show that the ectopic expression of miR‐305 has a deleterious effect on aging in Drosophila. To identify the targets of miR‐305, we performed RNA‐Seq. We discovered several mRNAs encoding antimicrobial peptides and insulin‐like peptides, whose expression changed in adults upon miR‐305 over‐expression. We further confirmed, by qRT‐PCR, that miR‐305 over‐expression significantly decreases the mRNA levels of four antimicrobial peptides. As these mRNAs contain multiple sequences matching the seed sequence of miR‐305, we speculate that a reduction in target mRNA levels, caused by ectopic miRNA expression, promotes aging.

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Source: Genes to Cells - December 1, 2017 Category: Genetics & Stem Cells Authors: Makiko Ueda, Tetsuya Sato, Yasuyuki Ohkawa, Yoshihiro H. Inoue Tags: ORIGINAL ARTICLE Source Type: research