CRISPR RNA

[1] CRISPR-Cas (clustered, regularly interspaced short palindromic repeats - CRISPR associated systems) is an adaptive immune system found in bacteria and archaea to protect against mobile genetic elements, like viruses, plasmids, and transposons.

[2] Pre-crRNA is formed after the transcription of the CRISPR locus and before being processed by Cas proteins.

Mature crRNA transcripts contain a partial conserved section of repeat and a sequence of spacer that is complementary to the target DNA.

[4] Type-I CRISPR systems are characterized by Cas3, a nuclease-helicase protein, and the multi-subunit Cascade (CRISPR-associated complex for antiviral defense).

[11] Type-V CRISPR systems are characterized by Cas12, a nuclease that can cleave ssDNA, dsDNA, and RNA.

[12] Type-VI CRISPR systems are characterized by Cas13, a single effector protein that targets RNA.