CRISPR (clustered regularly interspaced short palindromic repeat) , is an adaptive immune system that provides protection against mobile genetic elements (viruses, transposable elements and conjugative plasmids) . CRISPR clusters contain sequences complementary to antecedent mobile elements and target invading nucleic acids. CRISPR clusters are transcribed and processed into CRISPR RNA (crRNA) . This protein is a single-RNA guided endonuclease that is also capable of guiding crRNA processing; correct processing of pre-crRNA requires only this protein and the CRISPR locus (PubMed:26422227) .
