American molecular biologists created a new test system based on the CRISPR / Cas12 genomic editor to detect traces of a new type of coronavirus. According to scientists, it does not give false positive results.
“We created a quick and easy-to-use test by adapting CRISPR / Cas12 to search for viral RNA fragments in smears from the respiratory tract of patients. Our methodology is more visual and faster than systems based on PCR (polymerase chain reaction), which are used by the US Centers for Disease Control and Prevention. It correctly defines 95% of positive and 100% negative cases, ”the scientists write.
In recent months, scientists have created several variants of test systems that detect traces of a new coronavirus in a patient’s blood samples or secretions. As a rule, they are based either on the detection of RNA fragments of the pathogen COVID-19 using polymerase chain reaction (PCR) and its analogues, or on the detection of antibodies to a new type of coronavirus.
Initially, the accuracy of both the tests was extremely low, and their speed was quite low. In recent weeks and months, their quality has been improved sufficiently to conduct extensive epidemiological studies in a large number of carriers of coronavirus.
Bacterial Antivirus Tips
Specialists from the University of California at San Francisco (USA), as well as their colleagues from the California Department of Public Health, have developed an alternative to both methods. In their work, they used the genomic editor CRISPR / Cas12, which many bacteria use as a kind of “antivirus”.
Unlike the more popular and well-known “brother” of this system – CRISPR / Cas9 – it takes a little more effort to use it. However, it is much more accurate in recognizing editable sections of DNA and allows you to accurately “cut” them from the strand of the genetic code.
The authors of the article used this feature of CRISPR / Cas12 in order to make the search for SARS-CoV-2 virus in patient biofluid samples much more accurate. To do this, scientists have prepared a set of RNA tags that can “stick” to certain areas in two key genes of coronavirus. If this happens, the CRISPR / Cas12 system joins them and cuts the marks, after which they begin to glow. This makes it possible to detect the presence of the virus even with the naked eye.
Due to this, as the researchers note, it is possible not only to very accurately find traces of SARS-CoV-2 in the sample or to guarantee their absence, but also to distinguish fragments of coronavirus and its close relatives, the causative agent of SARS SARS and Middle Eastern fever MERS, as well as other coronaviruses .
The main plus of this approach, according to its creators, is not only its high accuracy, but also that its work does not require expensive equipment and specialized reagents. As the researchers hope, their CRISPR / Cas12 test will soon be approved for clinical use and will help doctors more accurately track the spread of the virus.