Abstract
MicroRNAs (miRNAs) are highly conserved, small noncoding RNAs that modulate posttranscriptional gene expression through as many as 100 mRNA targets. Previously, many miRNAs have been shown to play a role in regulating the aging process in multiple model organisms. This study shows that the levels of an abundant miRNA, mir-184, decrease with age in fly heads and manipulation of its levels in the whole fly as well as in specific tissues, such as glia and muscle, affect lifespan. Furthermore, we also identified mir-184 as a new member of the activin pathway as it is a downstream target of dFOXO and negatively regulates activin in the regulation of glia and muscle metabolism and aging.