The COVID-19 virus belongs to the family of coronaviruses, which are basically a large family of viruses that cause many ailments from the common cold to more serious illnesses such as Middle East respiratory syndrome (MERS-CoV) and acute respiratory syndrome. severe (SARS). CoV). To date, only six types of coronavirus are known to infect people. The virus that causes COVID-19 is the seventh and quite different from the others. In a new study, researchers at Academia Sinica in Taiwan identified a new “hidden” gene in SARS-CoV-2, the virus responsible for the current global health crisis, that may have contributed to its unique biology and pandemic potential.
Understanding overlapping genes is key to fighting the virus
In a virus that only has about 15 genes in total, knowing more about this and other overlapping genes, or “genes within genes,” could have a significant impact on how we fight the virus. The researchers say that overlapping genes may be one of the ways coronaviruses have evolved to replicate efficiently, thwart host immunity, or pass on. Knowing that there are overlapping genes and how they work can reveal new pathways for coronavirus control, for example through antiviral drugs.
The new gene triggers a strong antibody response
The research team identified ORF3d, a new overlapping gene in SARS-CoV-2 that has the potential to encode a protein that is longer than expected only by chance, according to the study published in the journal. eLife. They found that this gene is also present in a previously discovered pangolin coronavirus, perhaps reflecting the repeated loss or gain of this gene during the evolution of SARS-CoV-2 and related viruses. Furthermore, ORF3d has been independently identified and shown to elicit a strong antibody response in COVID-19 patients, demonstrating that the new gene protein is made during human infection.
Not detectable by a T cell response
Researchers do not yet know its function or if there is any clinical significance to the findings. But they predict that this gene is relatively unlikely to be detected by a T-cell response, in contrast to the antibody response. And maybe that has something to do with how the gene came to be. At first glance, genes may appear to be written language in the sense that they are made up of strings of letters (in RNA viruses, nucleotides A, U, G, and C) that convey information. But while language units (words) are discrete and do not overlap, genes can overlap and be multifunctional, with information encoded cryptically depending on where you start to “read.”
Overlapping genes are difficult to detect and most scientific computer programs are not designed to find them. However, they are common in viruses. This is in part because RNA viruses have a high mutation rate, so they tend to keep gene counts low to prevent a large number of mutations. As a result, viruses have developed a kind of data compression system in which one letter in their genome can contribute to two or even three different genes. The lack of overlapping genes puts us in danger of overlooking important aspects of viral biology, the researchers say, adding that, in terms of genome size, SARS-CoV-2 and its relatives are among RNA viruses. longest that exist. Thus, they are perhaps more prone to “genomic hoaxes” than other RNA viruses.
(With input from IANS)
Published: November 11, 2020 4:57 pm
