Gene editing is a relatively recent tool in biomedicine. CRISPR or genetic ‘cutter’ is a microscopic laboratory instrument capable of changing or editing pieces of a cell’s DNA. CRISPR-Cas9 uses a specially designed RNA molecule to guide an enzyme, called Cas9, to a particular sequence in DNA. Once there, Cas9 cuts the DNA strands there and removes a piece to put in its place a new piece of DNA. Thus, it would be possible to eliminate, for example, a gene that predisposes to a disease even before a person is born.
CRISPR’s promises are many and varied. Cas12 is, so to speak, an additional instrument that was added to the genetic ‘cutter’ toolbox in 2015. Cas12 is capable of cutting double-stranded DNA in places Cas9 cannot and, because it leaves edges irregular, it may be easier to use when inserting a new gene into the DNA cut.
Now, a laboratory has developed a test using CRISPR-Cas12 technology to detect the SARS-CoV-2 coronavirus , which has shown “highly reliable results in less than an hour.” Rapid tests are a fundamental tool for society that will allow us to control and mitigate the pandemic effectively.
At the moment, only a first initial validation of a clinical trial has been presented. In it, RNA from a patient sample was used. The RNA was called DETECTR (SARS-CoV-2 DNA Endonuclease-Targeted CRISPR Trans Reporter).
Cas12 is ‘trained’ to detect three SARS-like coronaviruses : SARS-CoV-2, a bat-like SARS-like coronavirus (bat-SL-CoVZC45) and SARS-CoV-1, for certain genes. Thus, Cas12 was able to detect predefined sequences of the coronavirus in the genetic material.
The screening test showed accurate results in a period of 30 to 40 minutes , as opposed to several hours needed by the most reliable tests used so far to detect the coronavirus. This promising trial could allow the development of tests outside of the clinical diagnostic laboratory, such as airports, local emergency departments, hospitals and other public and private places.
Although the majority of COVID-19 cases during the first month of the epidemic date back to the city of Wuhan in Hubei province in China, the continued increase in cases around the world appears to be driven by the transmission of the local community. Therefore, there is an urgent public health need for rapid diagnostic tests for SARS-CoV-2 infection, “cites the study, published April 16 in the journal Nature .
The major large-scale pandemics and epidemics of the last half century have been caused by zoonotic viruses (which come from animals). The researchers believe that a diagnostic method that can be easily adapted to detect not only infection from existing viruses, but a possible new infection from other emerging viruses is urgently needed.
Referencias:
‘CRISPR–Cas12-based detection of SARS-CoV-2’ (16 April 2020) Nature Biotechnology DOI: https://doi.org/10.1038/s41587-020-0513-4
