Coordinated networks of microRNAs and transcription factors with evolutionary perspectives.

MicroRNAs (miRNAs) and transcription factors (TFs) are two major classes of trans-regulators in gene regulatory networks. Coordination between miRNAs and TFs has been demonstrated by individual studies on developmental processes and the pathogenesis of various cancers. Systematic computational approaches have an advantage in elucidating global network features of the miRNA-TF coordinated regulation. miRNAs and TFs have distinct molecular and evolutionary properties. In particular, miRNA genes have a rapid turnover of birth-and-death processes during evolution, and their effects are widespread but modest. Therefore, miRNAs and TFs are considered to have different contributions to their coordination. The miRNA-TF coordinated feedforward circuits are considered to cause significant increases in redundancy but drastically reduce the target gene repertoire, which poses the question, to what extent is miRNA-TF coordination beneficial? Evolutionary analyses provide wide perspectives on the features of miRNA-TF coordinated regulatory networks at a systems level.