miR-184 modulates <i>Ilp8</i> to control developmental timing during normal growth conditions and in response to developmental perturbations

Organismal development depends on the precise coordination of growth and developmental timing, which is regulated by a complex interplay of factors. However, the mechanisms underlying this regulation are not fully understood. Post-transcriptional regulation by microRNAs plays a pivotal role in ensuring the proper timing of gene expression during growth and development. Here, we conducted a genetic screen to identify microRNAs that regulate developmental timing in Drosophila. Our screen identified miR-184, previously implicated in germline maturation and embryonic development, as a regulator of pupariation timing by acting in the larval imaginal discs. Using genetic and molecular approaches, we identified Drosophila Insulin-like peptide 8 (Dilp8; Ilp8), a secreted factor that is crucial for regulating developmental stability, as a target of miR-184. During normal larval development, miR-184 facilitates timely pupariation by regulating Ilp8 levels. Furthermore, we demonstrate that miR-184 plays an essential role in tissue damage responses by aiding in the induction of Ilp8 expression, which delays pupariation. These findings reveal a previously unreported post-transcriptional regulatory mechanism that links miR-184 to the control of developmental timing under normal growth conditions and in response to tissue damage.