Ecdysone‐induced microRNA miR‐276a‐3p controls developmental growth by targeting the insulin‐like receptor in Drosophila

Abstract Animal growth is controlled by a variety of external and internal factors during development. The steroid hormone ecdysone plays a critical role in insect development by regulating the expression of various genes. In this study, we found that fat body‐specific expression of miR‐276a , an ecdysone‐responsive microRNA (miRNA), led to a decrease in the total mass of the larval fat body, resulting in significant growth reduction in Drosophila . Changes in miR‐276a expression also affected the proliferation of Drosophila S2 cells. Furthermore, we found that the insulin‐like receptor ( InR ) is a biologically relevant target gene regulated by miR‐276a‐3p . In addition, we found that miR‐276a‐3p is upregulated by the canonical ecdysone signalling pathway involving the ecdysone receptor and broad complex. A reduction in cell proliferation caused by ecdysone was compromised by blocking miR‐276a‐3p activity. Thus, our results suggest that miR‐276a‐3p is involved in ecdysone‐mediated growth reduction by controlling InR expression in the insulin signalling pathway.