Unicellular Origin of the Animal MicroRNA Machinery (Current Biology)

In animals, microRNAs and the miRNA biogenesis machinery are essential for correct organismal development. Bråte et al. demonstrate that the core of this machinery, the Microprocessor, is not an animal innovation but originated among their unicellular relatives. Several unicellular species harboring the Microprocessor also express bona fide miRNAs.