Explanation: CRISPR-Cas9 is most commonly known to be a gene editor, but since its initial discovery, people have found that with some minor tweaks, CRISPR can be made to do a bunch of other things, things that biologists could have only dreamed of previously.
If you introduce a mutation that deactivates the Cas9 protein, the entire CRISPR complex still binds to DNA. Then, you can essentially glue whatever you want onto this modified Cas9 to produce a bunch of different effects:
- deactivated Cas9, no additional modifications: blocks other proteins from touching the DNA, which suppresses a gene without destroying it
- glue on some transcriptional activators: makes the cell express a gene
- glue on some fluorescent proteins: makes your DNA glow, lets you see where it is