Researchers have discovered a new “hidden” gene for SARS-CoV-2, the virus that causes COVID-19. The results of the research are published in the journal eLife.
Scientists suggest that the discovered gene – ORF3d – is the reason for the unique biology and pandemic potential of SARS-CoV-2. In a virus that has only about 15 genes, knowledge of this and other overlapping genes can make a big difference in the fight against the novel coronavirus.
Breaking genes, as their name suggests, overlap. Part of one of them is at the same time part of the other. Such genes are rare in cellular life forms, but common in viruses. Scientists believe that the fact is that the DNA (or RNA) molecules in viruses are very short. Therefore, evolution “found” a way to use the same region of the molecule in several genes at once.
In terms of genome size, SARS-CoV-2 and its relatives are some of the longest RNA viruses in existence.
The difficulty is that conventional genome reading techniques are not suited to identifying overlapping genes. Therefore, they are sometimes called hidden genes.
“Overlapping genes are responsible for the evolution of coronaviruses to replicate efficiently, suppress host immunity, or transmit infection,” explains lead author of the new study, Chase Nelson, a research fellow at Sinica Academy in Taiwan. In other words, this type of genes, like the discovered ORF3d, may well be responsible for the spread of the virus to the extent of a pandemic.
ORF3d, a new overlapping gene in SARS-CoV-2, is present in the previously discovered pangolin coronavirus. In addition, it is this gene that triggers a strong antibody response in COVID-19 patients.