A rotavirus is a wheel-shaped virus that gets its name from its complex shape ("rota" means wheel in Latin). Rotaviruses are composed of 11, double-stranded RNA segments which together encode six structural and six nonstructural proteins. Each virus has a multilayered protein coat made up of key structural proteins. The outer coat is made of VP4 and VP7 proteins. The VP4 forms spikes on the outer coat and attaches the virion to the host cell, playing a key role in cell penetration and virulence. Rotavirus’s VP7 protein, which forms most of the outer layer, is the main target for the host’s protective antibodies.
Researchers are studying rotaviruses’ structure to better understand pathogenesis—how the viruses infect hosts, replicate, and cause disease. Such understanding is crucial for the development of new drugs and vaccines to prevent and treat disease. Significant advances already have been made. For example, researchers have discovered that rotaviruses generate and reside in viral inclusion bodies known as viroplasms where new viruses are formed. Rotaviruses can reassort and exchange RNA segments between strains from different species. Enzymes that break down the outer protein layer can assist rotavirus replication, and calcium is important for assembling new virus particles. Rotavirus proteins may break down the host’s proteins, interfering with the host’s natural protection tools.
Researchers are examining the role of nonstructural proteins, which could be potential targets for antiviral drugs. The nonstructural protein 4, which alone can cause diarrhea in newborn mice, can take on different shapes and has functions inside and outside of infected cells. The nonstructural protein 2 is essential for genome replication and packaging. Neutralizing such protein functions could be important in developing effective rotavirus treatments.
For more information about basic research on rotavirus taking place at NIAID, read about the Rotavirus Molecular Biology Section in the Laboratory of Infectious Diseases.
Last Updated September 27, 2010
Last Reviewed June 11, 2010