The virulence regulator CovR boosts CRISPR-Cas9 immunity in Group B Streptococcus.

ABSTRACT: CRISPR-Cas9 immune systems protect bacteria from foreign DNA. However, immune efficiency is constrained by Cas9 off-target cleavages and toxicity. How bacteria regulate Cas9 to maximize protection while preventing autoimmunity is not understood. Here, we show that the master regulator of virulence, CovR, regulates CRISPR-Cas9 immunity against mobile genetic elements in Streptococcus agalactiae, a pathobiont responsible for invasive neonatal infections. We show that CovR binds to and represses a distal promoter of the cas operon, integrating immunity within the virulence regulatory network. The CovR-regulated promoter provides a controlled increase in off-target cleavages to counteract mutations in the target DNA, restores the potency of old immune memory, and stimulates the acquisition of

SUBMITTER: Pastuszka A 

PROVIDER: S-EPMC12216829 | biostudies-literature | 2025 Jul

REPOSITORIES: biostudies-literature