Utrecht. The replication of a virus in a body cell can be recorded in a kind of video. The new method by which individual virus particles are made visible is presented by Dutch researchers in Magazin “Cell” in front. The authors of the study led by Sanne Boersma from the Hubrecht Institute in Utrecht believe that the approach can also be transferred to other RNA viruses such as the new coronavirus Sars-CoV-2.
RNA viruses multiply by entering a body cell and abusing its molecular mechanisms for their own purposes. Simply put, the cell is forced to help produce RNA proteins from viruses. This leads to the formation of new viruses which can then infect other cells.
Investigate the virus infection in real time
For their new method, Boersma’s team manipulated the Coxsackievirus B3 (CVB3) RNA so that the virus proteins made from it were visible in a special microscope. This enabled the researchers to observe how a virus penetrates a cell and reproduces itself. The researchers identified a weakness in the viruses studied.
The study’s authors call their method Virim: Virus Infection Real-Time Imaging. In German you could say real-time imaging for viral infections. “With this new method we can answer many important questions about viruses,” says Boersma in a statement from her institute.
In contrast to most common research methods, Virim allows scientists to study viral infections in real time and on living cells. Under the microscope, they can even observe individual cells that have been attacked with high spatial resolution.
Up to 29 percent of the cells were dead ends
The manipulated RNA makes virus proteins visible under the microscope as light green dots. With these dots, the researchers can differentiate between five phases of an infection, with an increasing number of luminous dots indicating that the virus is multiplying.
The researchers were particularly interested in observing that the virus was unable to replicate its RNA in 15 to 20 percent of human host cells. “These host cells were infected with a virus, but the virus could not multiply,” explains Boersma. The cells in question were a dead end for the virus, although the cells usually died quickly.
Stop the reproduction process as soon as possible
In another experiment, the scientists supported the immune system of cells with the help of a certain signal protein. This activates genes that are particularly effective against tumors and viruses. Now the researchers could see in significantly more cells that the virus entered, but was stopped early in the replication process. “The first step in the reproductive process is the Achilles heel of this virus: this moment determines whether the virus can spread further,” emphasizes Boersma.