How does CRISPR-Cas9 work?

CRISPR-Cas9 is a powerful tool used for genome editing. Here's how it generally works:

1. Recognition: Cas9, a type of enzyme, is guided by CRISPR RNA (crRNA) to a specific sequence of DNA that matches the crRNA.

2. Binding: Cas9 binds to the target DNA sequence through base-pairing interactions between the crRNA and the DNA.

3. Cutting: Once bound, Cas9 cuts both strands of the DNA at the targeted location, creating a double-strand break (DSB).

4. Repair: Cells naturally repair DSBs through two main mechanisms:

   • Non-Homologous End Joining (NHEJ): Often introduces small insertions or deletions (indels) at the cut site, disrupting the gene.
   • Homology-Directed Repair (HDR): Uses a DNA template to guide repair, allowing precise editing by introducing desired changes.

5. Applications: CRISPR-Cas9 can be used to:

   • Knockout: Disable a gene by disrupting its sequence.
   • Knock-in: Insert new sequences or correct mutations.
   • Regulation: Target specific genes for activation or repression.

CRISPR-Cas9 has revolutionized genetic research and holds potential for treating genetic disorders and advancing biotechnology.