SARS-CoV Hacks Cells' Hardware.

• Position: COVID-19

Severe symptoms of COVID-19, often leading to death, are thought to result from the patient's own acute immune response rather than from damage inflicted directly by the virus. Intensive research efforts therefore are seeking to determine how the SARS-CoV-2 virus manages to mount an effective invasion while throwing the immune system off course.

A study published in Nature reveals a multipronged strategy that the virus employs to ensure its quick and efficient replication while avoiding detection by the immune system. The study was conducted jointly by the research groups of Noam Stern-Ginossar at the Weizmann Institute of Science and Nir Paran and Tomer Israely of the Israel Institute for Biological, Chemical and Environmental Sciences.

During an infection, human cells normally are able to recognize that they are being invaded and quickly dispatch signaling molecules, which alert the immune system of the attack. With SARS-CoV-2, it was apparent early on that something was not working quite right--not only is the immune response delayed, enabling the virus to replicate quickly unhindered, but once this response does occur, it often is so severe that instead of fighting the virus it causes damage to its human host.

"Most of the research that has addressed this issue so far concentrated on specific viral proteins and characterized their functions. Yet, not enough is known today about what is actually going on in the infected cells themselves," says Stern-Ginossar, who is in Weizmann's Department of Molecular Genetics. "So, we infected cells with the virus and proceeded to assess how infection affects important biochemical processes in the cell, such as gene expression and protein synthesis."

When cells are infected by viruses, they start expressing a series of specific antiviral genes--some act as first-line defenders and meet the virus head on in the cell itself, while others are secreted to the cell's environment, alerting neighboring cells and recruiting the immune system to combat the invader. At this point, both the cell and the virus race to the ribosomes, the cell's protein synthesis factories, which the virus itself lacks...