A miRacle in plant development: role of microRNAs in cell differentiation and patterning.

MicroRNAs (miRNAs) are endogenous small regulatory RNAs, which control gene expression in eukaryotes. In plants they repress mRNA targets containing a highly complementary site, either by cleavage or translational repression. Studies of individual miRNA/target interactions highlight the involvement of the miRNA-based regulations in a broad range of developmental programs, throughout plant lifecycle. MicroRNAs can have distinct regulatory functions on their targets: some determine their spatial accumulation, some have a buffering role that ensures the robustness of their expression pattern, and finally others establish the temporal expression of targeted genes.