Spacer acquisition by Type III CRISPR-Cas system during bacteriophage infection of Thermus thermophilus.

ABSTRACT: Type III CRISPR-Cas systems provide immunity to foreign DNA by targeting its transcripts. Target recognition activates RNases and DNases that may either destroy foreign DNA directly or elicit collateral damage inducing death of infected cells. While some Type III systems encode a reverse transcriptase to acquire spacers from foreign transcripts, most contain conventional spacer acquisition machinery found in DNA-targeting systems. We studied Type III spacer acquisition in phage-infected Thermus thermophilus, a bacterium that lacks either a standalone reverse transcriptase or its fusion to spacer integrase Cas1. Cells with spacers targeting a subset of phage transcripts survived the infection, indicating that Type III immunity does not operate through altruistic suicide. In the absence of s

SUBMITTER: Artamonova D 

PROVIDER: S-EPMC7515739 | biostudies-literature | 2020 Sep

REPOSITORIES: biostudies-literature