Mismatch type impacts interference and priming activities in the type I-E CRISPR-Cas system.

ABSTRACT: Type I-E CRISPR-Cas systems direct RNA-guided interference against foreign nucleic acids using the CRISPR RNA (crRNA)-guided Cascade complex and Cas3 helicase-nuclease. DNA targeting by Cascade-Cas3 promotes priming, a mechanism that allows for rapid acquisition of new spacers within the CRISPR array. Target mutations in the PAM and PAM-proximal seed region can block interference but may still allow priming. Previous studies have suggested that target mutations to T and A are tolerated, but that C and G substitutions are deleterious to interference and priming, respectively. However, the contributions of the crRNA spacer sequence to mutational tolerance remain unclear. Here, we systematically tested the effects of crRNA seed sequences on mutational tolerance. We engineered four E. coli<

SUBMITTER: Phan PT 

PROVIDER: S-EPMC12871591 | biostudies-literature | 2026 Jan

REPOSITORIES: biostudies-literature