"Coronaviruses are a very large family of RNA viruses," Hogue says. "They infect humans and a broad range of animals." While the symptoms produced by coronavirus infection in humans tend to be respiratory, in animals, such viruses can cause a range of severe problems, from neurological ailments to immunosuppressive effects. Various coronaviruses are responsible for common colds in humans, though the combined upper and lower respiratory symptoms and gastrointestinal complications seen in SARS patients are unusual.
In the study reported in Journal of Virology, Hogue and her team closely examined one of the major proteins found in the coronavirus that is crucial to the pathogen's process of assembly. Known as the M, it is one of four proteins, in addition to S, N and E, required to produce a fully assembled viral particle, capable of infecting a host.
The membrane (M) protein makes up the bulk of the outer shell or envelope of the virus, forming a lattice that surrounds and shields the viral genome. The spike protein (S)named for its spike-like or crown-like appearance under electron microscopy, is critical for allowing the coronavirus to attach to the host cell's receptors, prior to viral entry into the cell. The nucleocapsid (N) protein encapsidates the genomic RNA. The envelope or E protein is the least plentiful protein known to play a central role in virus assembly, though its presence is very important. In addition to assisting viral assembly, the E protein also appears to be involved in shuttling the newly assembled virions out of the cell, enabling these particles to escape and infect other host cells in the exponential process of viral infection.
The group wanted to determine the requirements for the M protein to function
|Contact: Joseph Caspermeyer|
Arizona State University