CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) are segments of short, regularly placed palindromic nucleotide repetitions. CAS (CRISPR-Associated Protein) is a CRISPR-associated nuclease enabling controlled DNA cleavage.
CRISPR/Cas9 systems allow for targeted gene editing. Briefly, aCRISPR/Cas9 complex binds to a specific DNA sequence, cuts it out and replaces the original sequence with a new sequence. Guide RNA (gRNA) helps to navigate the CRISPR/Cas9 complex in order to target only the specific sequence.
CRISPR/Cas9 represents a valuable tool in gene editing and becomes even more popular in therapy, especially of cancer and other disease involving genetic defects (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6315587/).
Picture: CRISPR/Cas9 induced DNA double-strand break.