Science explains: CRISPR diagnostics
CRISPR, the molecular scissors that shot to fame in 2012, has revolutionized biology because it makes it simpler and cheaper for scientists to cut genomes wherever they chose. The power of CRISPR lies in what happens after it makes a cut. Theoretically, the natural system that repairs cuts can cripple disease-causing genes. Or scientists can swap in new DNA potentially fixing, say, the mutation that causes sickle-cell anemia. Recently, several labs have manipulated the CRISPR platform for diagnostics — to simplify detection of viruses or even tumors. CRISPR complex finds a targeted part of a genome with a guide RNA. The guide tows along an enzyme from what’s known as the Cas family that does the actual cutting. But Cas enzymes come in many varieties. after they make the targeted cut, Some go into a feeding frenzy and cut any single stranded nucleic acids nearby. These are the Cas enzymes used in detection systems. Imagine blood from a patient suspected of having Zika. Basically, researchers could prep the sample, add all the necessary ingredients, and then spike it with a piece of single stranded DNA or RNA that has a fluorescent reporter system attached to it. If CRISPR finds Zika, The Cas enzyme cuts the virus and cuts the molecule holding the reporter, which makes it fluoresce. The latest versions of these systems, nicknamed SHERLOCK and DECTECTR, have shown that they simultaneously can find several different viruses or mutations associated with tumors. The researchers also have made progress on moving CRISPR based detections to test strips, similar to what’s used in pregnancy tests. One day, they envision it may be possible with just a drop of blood, to have an easy-to-read result that tells doctors whether a patient has Zika virus or its close cousin Dengue. A multi-channeled strip may also reveal which type of dengue. First genome editing, now diagnostics– where will CRISPR take us next?