CRISPR is known as the genome-editing power house so far. Recently scientists have discovered a far more superior diagnostic tool known as SHERLOCK. That achievement described in Science, would pave way for quick, easy, cheap and precise diagnostic tests.
Researchers have developed a promising method for detecting extremely low concentrations of genetic material. Though there is a long way to demonstrate practicality, it would provide promising clinical results.
The scientists, led by bioengineer James Collins and CRISPR pioneer Feng Zhang of the Broad Institute of MIT and Harvard, named their system SHERLOCK (for Specific High sensitivity Enzymatic Reporter unlocking).
It works in a standard test tube or on glass fiber paper and can work on body heat, offering hope that it could be used in places with no high-tech lab equipment such as the Ebola epidemic in west Africa in 2013-2016 or last year’s Zika outbreak. In contrary to the work horse of DNA detection, known as PCR – requires sophisticated lab processes, equipment and heat to make the reaction run.
The best known CRISPR system consists if a “guide” molecule of RNA darts around a genome until it finds a precise sequence of chemical letter- A, T, G, C. It also has molecular scissors that snips out the targeted sections of DNA- in a disease-causing gene for instance- so that the double helix can repair itself with healthy DNA.
SHERLOCK differs in many ways. It begins with a molecule that finds a sequence of DNA in a test tube and rapidly make several copies of it. Other molecules turn the amplified DNA into its cousin, RNA. Then a CRISPR enzyme called Cas 13a, works: Unlike CRISPR scissors, it doesn’t stop once it has cut the RNA that scientists target, instead it also cuts and cuts the more near RNA no matter its sequence, in what the researchers call “collateral Cleavage” All the chopping generates a fluorescent signal that could be detected with a $200 device or sometimes with a naked eye.
SHERLOCK can pick out unique stretches of the genetic material in Zika and dengue viruses and could also differentiate them. SHERLOCK could be used in challenging field conditions of an epidemic. This could also detect ZIKA in urine rather than more invasive and risky blood tests.
SHERLOCK could detect tumor DNA when there was thousand times more molecules of healthy DNA. This proves very beneficial for medical use.
Scientists have filed several US patent applications on SHERLOCK including for uses in detecting viruses, bacteria and cancer causing mutations.