A gene sequencing study was presented online in Science this week, describing the genomes of all known rhinoviruses. The study was published by researchers from the Universities of Wisconsin and Maryland and the J. Craig Venter Institute in Rockville, MD. A rhinovirus (RV) is a small non-enveloped virus containing a single-stranded RNA genome within an icosahedral (20-sided) capsid, and belonging to the Picornaviridae family. RV can be divided into 2 groups depending on their affinity for certain cellular receptors. Picornaviridae, unlike retroviruses, replicate their plus-strand RNA genome by use of an RNA polymerase which generates a negative-strand RNA that serves as a template for replication. Rhinoviruses are often associated with the common cold and pneumonia, in addition to other infections of the respiratory system. RV doesn't replicate well at body temperature but more optimally at 33-35 degrees celcius. The incubation period for infection is 2-3 days and infection, while it causes the typical cold symptoms (sore throat, sneezing, coughing, nasal congestion and discharge), doesn't cause any permanent damage to the skin (epithelium) of the respiratory tract.
According to a previous study by Proud et al. (2008), RV infection does alter gene expression in it's host, having an effect on the immune response, particularly production of antivirals and chemokines. The sequencing study revealed some conserved sequences as well as the differences between the many strains of RV that prevent the development of vaccines and cure-all treatments for the common cold.
Sources:
Palmenberg et al. 2009. Sequencing and analyses of all known human rhinovirus genomes reveals structure and evolution. Science Express. February 12, 2009. doi:10.1126/science.1165557
Proud et al. 2008. Gene expression profiles during in vivo human Rhinovirus infection. American Journal of Respiratory and Critical Care Medicine. 178:962-968. doi:10.1164/rccm.200805-670OC
Gerber et al. 2001. Biochemical and genetic studies of the initiation of human rhinovirus 2 RNA replication: purification and enzymatic analysis of the RNA-dependent RNA polymerase 3Dpol. J. Virology 75(22):10969-10978. doi:10.1128/JVI.75.22.10969-10978.2001
Comments