A rotavirus is a wheel-shaped virus whose name is derived 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 two proteins, VP4 and VP7. 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. As a result of this research, researchers have discovered that rotaviruses generate and reside in viral inclusion bodies known as viroplasms, where new viruses are formed. Rotaviruses can re-assort and exchange RNA segments between strains from different species. Also, 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. In addition, NIAID-supported researchers have developed a model to grow and study the virus in intestine-like tissue called induced human intestinal organoids. This promising new approach will help scientists better understand how rotavirus and other gastrointestinal viruses cause disease, as well as help inform development of new interventions for infants in low and middle income countries.
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 June 23, 2015