Conditional activation of Cas13 enforces lysogeny in a native type VI-A CRISPR host (Nature Microbiology)

Godsil, Wei and Meeske report in Nature Microbiology that the Listeria seeligeri type VI-A CRISPR system restricts the lytic cycle of temperate phages but tolerates prophage acquisition and interferes with prophage induction through a non-abortive mechanism. When induction is attempted, Cas13 activation forces prophage re-integration and so maintains lysogeny, and during polylysogenic induction it restricts only the targeted phage; the authors say this lets type VI hosts acquire potentially beneficial prophages while mitigating lysis.