Scientists believe that research will help broaden our understanding of the Sars-CoV-2 infection mechanism.
Researchers at the Weizmann Institute of Science and the Israel Institute for Biological Research have discovered 23 new proteins involved in Sars-CoV-2 infection.
In the study, recently published in the journal Nature, scientists say the finding may explain why the new coronavirus is so efficient in infecting human cells.
The team developed a new analysis approach based on the idea that RNA translation – the process of converting RNA instructions into proteins that are manufactured in the cell – could be much more informative and would not need an earlier mapping of the virus.
To do this, the scientists infected cells in laboratory cultures with the new coronavirus and then focused on the activity of the ribosomes, which are the cell’s protein-manufacturing plants.
These organelles recognize Sars-CoV-2 as a messenger RNA, which is essential for the functioning of our cells, and soon start working by translating various parts of the viral RNA sequence into amino acids that together form a protein.
In the experiment, as ribosomes pumped strands of viral proteins, scientists froze the cells and then detected all of the ribosomes and their products.
Most of the amino acid sequences were short and formed peptides, which can play a regulatory role.
There were also four complete proteins that, regardless of their function, can serve as antigens – foreign proteins that alert the host’s immune system.
In addition, the researchers realized that other proteins that should be present, at least according to various computational models, were missing.
Scientists hope that further research on these proteins will lead to a better understanding of how Covid-19 progresses, as well as better treatment options for the disease.
“The ribosome profiling method enabled us not only to precisely identify the sequences on the viral genome that get translated to protein, it gave us accurate quantities of the various proteins,” said Dr. Noam Stern-Ginossar, one of the researchers.
Why has Sars-CoV-2 been so successful in infecting humans?
According to the team, the epithelial cells that line our lungs are, as was suspected, the best hosts for the virus.
In addition, they observed that Sars-CoV-2 replicates very quickly, causing the amount of viral RNA in the cell to quickly exceed human RNA.
“We had enough information to compare SARS-CoV-2 with related coronaviruses, as well as with existing projections,” Stern-Ginossar said. “The differences enabled us to identify genetic sequences encoding previously unknown proteins belonging to SARS-CoV-2.”