Prokaryotic Argonautes Function beyond Immunity by Unlinking Replicating Chromosomes.

Eukaryotic Argonaute proteins strictly mediate RNA-guided RNA interference. In contrast, prokaryotic Argo-nautes can utilize DNA guides to target complementary DNA sequences to protect their hosts against invading DNA. In this issue of Cell, Jolly and colleagues demonstrate that Thermus thermophilus Argonaute additionally participates in DNA replication by unlinking catenated chromosomes.