Saccharomyces cerevisiae as a model host for studying gene expression and RNA replication of positive-strand RNA viruses

Many viruses that infect plants or animals are positive strand RNA viruses;they are classified in 20 families and 88 genera. Because the genes that are involved in replication are essentially conserved among viruses in the genera, these viruses can also be grouped into three large supergroups or superfamilies.although these groupings have no taxonomic connotation. Given the basic similarities among members of each of these supergroups, research data can be compared for understanding the basic mechanisms involved in virus genome replication and, in particular, how the host cell contributes to this process. The use of the budding yeast, Saccharomyces cerevisiae. was a breakthrough in these types of studies because systems were developed that have allowed replication in yeast cells of some (+)RNA plant (bromoviruses and tombusviruses) and animal (nodaviruses) viruses. Using yeast cells, many advances have been made in the comprehension of the virus-host interactions that lead to the formation of functional replication complexes and of the involvement in the process of several host genes.