Cas3 stimulates runaway replication of a ColE1 plasmid in Escherichia coli and antagonises RNaseHI.

ABSTRACT: Cas3 nuclease-helicase is part of CRISPR immunity systems in many bacteria and archaea. In type I CRISPR, Cas3 nuclease degrades invader DNA that has been base-paired to crRNA as an R-loop within a "Cascade" complex. An R-loop is a DNA-RNA hybrid that includes a displaced single-strand DNA loop. Purified Cas3 from E. coli and the archaeon M. thermautrophicus can process R-loops without DNA/RNA sequence specificity and without Cascade. This has potential to affect other aspects of microbial biology that involve R-loops. Regulatory RNAs and host cell proteins modulate replication of ColE1 plasmids (e.g., pUC) from R-loop primers. We observed that Cas3 could override endogenous control of a ColE1 replicon, stimulating uncontrolled ("runaway") replication and resulting in much higher plasmid y

SUBMITTER: Ivancic-Bace I 

PROVIDER: S-EPMC3737335 | biostudies-literature | 2013 May

REPOSITORIES: biostudies-literature