Virginia Commonwealth University Institute of Molecular Medicine researchers have traced the evolutionary origin of two genes that serve as primary cellular sensors of infection with RNA viruses, such as influenza, poliovirus, West Nile virus, and HIV, which may ultimately provide researchers with insight into a possible new pathway for the development of innate immunity.
Recent studies by other investigators have provided information on exactly how humans respond to virus infection and the role of innate immunity in protection from viral pathogenesis. Induction of innate immunity is closely associated with the production of type I interferons. Interferons are a class of proteins that are secreted by the body in response to a viral infection such as rhinovirus, the cause of the common cold.
In the study, published online in the Early Edition of the Proceedings of the National Academy of Sciences the week of October 20-24, the VCU team reported that melanoma differentiation associated gene-5 (MDA-5) and retinoic acid inducible gene-I (RIG-I) originated specifically in mammals. These genes induce the production of type I interferons.
“Understanding how these unique genes developed and evolved provides a unique opportunity to understand the origins of innate immunity and to develop ways of exploiting this process to develop new types of therapies for pathogenic viruses,” said lead investigator Paul B. Fisher, M.Ph., Ph.D., professor and chair of the Department of Human and Molecular Genetics and director of the VCU Institute of Molecular Medicine in the VCU School of Medicine.