| microRNAs (miRNAs) are a group of small non-coding RNAs that negatively regulate their target message RNAs (mRNAs) in a posttranscriptional manner, leading to translational repression and/or mRNA degradation. They possess high evolutionary conservation and are involved in multiple major biological processes. Here, I focus on the transcriptional and posttranscriptional control of miRNAs in animals by steroid hormones, which are involved in diverse physiological events and known to promote major transitions between developmental stages. The steroid hormone control of miRNAs will be addressed in different organisms, including worms, flies and vertebrates, to show its evolutionary conservation. Although the specific factors involved vary in different organisms, the main clues of steroid hormone control of miRNAs are conserved in different organisms and thus this regulatory mechanism might be of evolutionary significance. Furthermore, as increasing evidence shows that miRNAs can in turn regulate the components of steroid hormone pathway, especially nuclear hormone receptors that are a group of steroid hormone responsive transcription factors, this review will also address the complex relationship between steroid hormone pathways and miRNAs as feedback regulatory circuits. |
