Genetics of the rotaviruses

Absence of superinfection exclusion during asynchronous reovirus infections of mouse, monkey, and human cell lines

Reovirus is a gastroenteric virus with a genome that consists of ten segments of double-stranded RNA. The segmented nature of the genome allows for genetic mixing when cells are simultaneously infected with two different viral serotypes. The ability of viral reassortment to take place in asynchronous infections has not previously been investigated with mammalian reoviruses. In this study, five different cell lines, representing mouse, monkey, and human, were infected synchronously or asynchronously with various sets of two different temperature-sensitive (ts) reovirus mutants in order to study the genetic interactions which occur. Recombinant viruses were detected at high frequency when infection by the two different ts mutants was separated by as much as 24 h, suggesting that superinfection exclusion does not play a role in reovirus mixed infections. The apparent lack of superinfection exclusion in reovirus infections may have important implications in its evolution.

Genetics of the rotaviruses

Genetic analyses have contributed significantly to our understanding of the biology of the rotaviruses. The distinguishing feature of the virus is a genome consisting of 11 segments of double-stranded RNA. The segmented nature of the genome allows reassortment of genome segments during mixed infections, which is the major distinguishing feature of rotavirus genetics. Reassortment has been a powerful tool for mapping viral mutations and other determinants of biological phenotypes to specific genome segments. However, more detailed genetic analysis of rotaviruses is currently limited by the inability to perform reverse genetics. Development of a reverse genetic system will facilitate analysis of the molecular mechanisms involved in various genetic, biochemical, and biological phenomena of the virus.