engleski

Interplay of host nucleases, RecBCD and CRISPR-Cas adaptation in Escherichia coli

CRISPR-Cas system is a prokaryotic adaptive immune system against foreign genetic elements. Immunity is acquired through insertion of small fragments of invader DNA (“protospacers”) into a CRISPR array, where they are called spacers. This process of spacer acquisition is called adaptation and can be mediated solely by the protein complex Cas1-Cas2, known as “naïve CRISPR adaptation”. Spacer integration can be separated into three steps: substrate capture/uptake, recognition of the CRISPR locus, and integration within the CRISPR array followed by duplication of the associated repeat sequences. Mechanistic detail of DNA integration is well understood but much less is known about events generating DNA for capture by Cas1-Cas2. In E. coli, RecBCD is thought to aid naïve adaptation by generating single-stranded DNA intermediates that are reannealed and further processed by Cas1-Cas2, and then integrated into the CRISPR array. In this work, we wanted to better understand the role of the RecBCD in prespacer preparation and the role of host nucleases in this process.

CRISPR ; RecBCD ; Cas1-Cas2 ; nucleases ; E. coli

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