miR-184 modulates Ilp8 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.