Unraveling the mystery that makes viruses infectious

The researchers first identified how viruses such as poliovirus and the common cold virus ‘package’ their genetic code, allowing them to infect cells.

The results, published today in the journal PLOS Pathogens by a team from the Universities of Leeds and York, opens up the possibility that drugs or antiviral agents can be developed to prevent these infections.

After a cell is infected, the virus needs to spread its genetic material to other cells. This is a complex process that involves creating what are known as virions – newly formed infectious copies of the virus. Each virion is a protein shell that contains a complete copy of the virus’s genetic code. Virions can then infect other cells and cause disease.

What has been a mystery until now is a detailed understanding of how the virus assembles these virions children.

Professor Peter Stockley, former director of the Astbury Center for Structural Molecular Biology in Leeds, who oversaw the research with Professor Reidun Twarock of York, said: “This study is extremely important because of the way it changes our thinking about how we can control some viral diseases. If we can stop the mechanism of virion formation, then there is the potential to stop an infection in its path. “

“Our analysis suggests that the molecular characteristics that control the virion formation process are genetically conserved, which means that they do not mutate easily – reducing the risk that the virus could change and render any new drug ineffective.”

The research in Leeds and York brings together experts in the molecular structure of viruses, electron microscopy and mathematical biology.

The study focuses on a harmless bovine virus that is not infectious in people, Enterovirus-E, which is the universally adopted substitute for poliovirus. Poliovirus is a dangerous virus that infects people, causing polio and is the target of an initiative to eradicate the virus from the World Health Organization.

The group of enteroviruses also includes the human rhinovirus, which causes the common cold.

The study published today details the role of so-called RNA packaging signals, small regions of the RNA molecule that, together with the proteins in the virus envelope, ensure the precise and efficient formation of an infectious virus.

Using a combination of molecular biology and mathematics, the researchers were able to identify possible locations on the RNA molecule that could act as packaging signals. Using advanced electron microscopes from the Astbury Biostructure Laboratory at the University of Leeds, scientists were able to directly visualize this process – the first time that it has been possible with any such virus.

Professor Twarock added: “Understanding in detail how this process works, and the fact that it appears to be conserved in an entire family of viral pathogens, will allow the pharmaceutical industry to develop antiviral agents that can block these important interactions and prevent disease.”