RNA-dependent RNA polymerase (RdRp) in the Cardiovirus genus of positive-sense single-stranded RNA [(+)ssRNA] viruses, within the family Picornaviridae
This group contains the RdRp of RNA viruses belonging to the Cardiovirus genus within the family Picornaviridae, order Picornavirales. Member viruses have a (+)ssRNA genome. Vertebrates serve as natural hosts for the cardioviruses. There are currently six species in the genus: Cardiovirus A-F. Diseases associated with cardioviruses include: myocarditis, encephalitis, multiple sclerosis, and type 1 diabetes. Cardiovirus A is composed of only one serotype, encephalomycarditis virus (EMCV) which causes encephalomyocarditis and reproductive disease in pigs. Cardiovirus B comprises 15 genetic types, Theiler's murine encephalomyelitis virus (TMEV), Vilyuisk human encephalomyelitis virus (VHEV), thera virus (formerly named Theiler-like virus of rats), Saffold virus (SAFV) types 1 to 11, and genet fecal theilovirus (from Geneta geneta). Of these types, only VHEV and SAFV are thought to cause infection in humans. Thus far, Cardiovirus C has only been observed in the brown rat. The RdRp domain displays a right hand with three functional subdomains, called fingers, palm, and thumb. All RdRps contain conserved polymerase motifs (A-G), located in the palm (A-E motifs) and finger (F-G) subdomains. All these motifs have been implicated in RdRp fidelity such as processes of correct incorporation and reorganization of nucleotides.
Jiyao W et al.(2023). "The conserved domain database in 2023.",