Eukaryotic Argonaute proteins participate in RNA-guided RNA silencing pathways and are divided into AGO and PIWI clades, with functional and mechanistic differences. Here, the authors show that a deep-branching PIWI protein from Asgard archaea (the closest prokaryotic relatives of eukaryotes) displays hybrid features and may reflect an ancestral molecular architecture that preceded the divergence of eukaryotic AGOs and PIWIs.
- Carolien Bastiaanssen
- Pilar Bobadilla Ugarte
- Fabai Wu
