A dynamic subpopulation of CRISPR-Cas overexpressers allows Streptococcus pyogenes to rapidly respond to phage.

ABSTRACT: Many CRISPR-Cas (clustered regularly interspaced short palindromic repeats and CRISPR-associated protein) systems, which provide bacteria with adaptive immunity against phages, are transcriptionally repressed in their native hosts. How CRISPR-Cas expression is induced as needed, for example, during a bacteriophage infection, remains poorly understood. In Streptococcus pyogenes, a non-canonical guide RNA tracr-L directs Cas9 to autorepress its own promoter. Here we describe a dynamic subpopulation of cells harbouring single mutations that disrupt Cas9 binding and cause CRISPR-Cas overexpression. Cas9 actively expands this population by elevating mutation rates at the tracr-L target site. Overexpressers show higher rates of memory formation, stronger potency of old memories and a larger memo

SUBMITTER: Stoltzfus MJ 

PROVIDER: S-EPMC11983678 | biostudies-literature | 2024 Sep

REPOSITORIES: biostudies-literature