Schematic model of the regulatory network of sense–antisense miRNA pairs. In a cell, a few miRNAs and their antisense transcripts are coexpressed. miRNA-ATs can be protein-coding genes or ncRNAs that function dependently or independently of their sense miRNAs. Because of the mode of miRNA-mediated regulation, the sense-mature miRNAs may bind to the perfectly complementary sequences in the miRNA-ATs that are opposite to the pre-miRNA regions and repress their expression. RNA editing in miRNA-ATs further modulates the repression effect of sense miRNAs and in most cases, it decreases the accessibility of miRNA-ATs and protects them from being degraded by the sense-mature miRNAs. Meanwhile, the act of the transcription and/or the transcripts of miRNA-ATs may regulate the expression of the sense miRNAs. The reciprocal interactions between miRNAs and miRNA-ATs may ultimately determine the expression landscape of a substantial fraction of miRNAs and miRNA-ATs in different types of human tissues or cells.
