Small changes in a person’s genetic makeup may help explain why some people have a strong natural defense against COVID infection, while others develop severe disease, according to a new study.
Scientists at the MRC-University of Glasgow Center for Virus Research have pinpointed a gene encoding a particular protein called OAS1, which is believed to play a key role in shaping the early stages of a person’s response to Sars-CoV-2. Is – the virus that causes covid-19.
When a human cell is infected, the OAS1 protein is able to sense the presence of the virus. This jumps into action, and kick-starts a chain of events involving the activation of an RNA-killing enzyme, causing the cell to begin attacking the virus’s genetic material.
the study, published in the journal Science, suggesting that some express a more protective version of OAS1 that is ‘prenylated’. It is the addition of a single molecule of lipid to a protein encoded by the OAS1 gene.
Because coronaviruses hide inside cells and replicate their genomes inside vesicles made of lipids, prenylated OAS1 is better suited to seek out Sars-CoV-2 and direct the cellular weapon to attack it.
In hospitalized patients, the prenylated version of the gene was associated with better outcomes from severe COVID-19. Those without it had worse clinical outcomes than those without; These patients were 1.6 times more likely to be admitted to ICU or death, the study said.
The researchers also found that, about 55 million years ago, this protective gene was deleted in horseshoe bats – one of the presumed sources of SARS-CoV-2.
As such, it means that the virus does not need to be adapted to escape this particular defense line, which therefore remains effective for some humans in providing protection.
But if Sars-CoV-2 mutates and acquires the ability to bypass the defenses generated by prenylated OAS1 proteins, the virus could potentially become more lethal or transmissible.
Professor Sam Wilson, a virologist at the Center for Virus Research, said: “We know that viruses are adaptive, and even Sars-CoV-2 may have adapted to replicate in animal reservoirs in which it spreads out.
“Cross-species transmission in humans exposed the virus Sars-CoV-2 to a new repertoire of antiviral defense, some of which Sars-CoV-2 may not know how to avoid.
Credit: www.independent.co.uk /