Viral RNA-directed RNA polymerase, C-terminal (IPR020237)

Short name: vRNA-dir_pol_C

Overlapping homologous superfamilies


Domain relationships



This is the C-terminal of RNA-directed RNA polymerase (Protein A) found in Alphanodaviruses such as Flock House Virus (FHV). FHV is a positive-stranded RNA virus with a bipartite genome of RNAs, RNA1 and RNA2. RNA1 encodes protein A, which is the catalytic subunit of the RNA-dependent RNA polymerase (RdRp) [PMID: 24100569] and functions as the sole viral replicase protein responsible for RNA replication. FHV protein A also possesses a terminal nucleotidyl transferase (TNTase) activity, which is able to restore the nucleotide loss at the 3'-end initiation site of RNA template to rescue RNA synthesis initiation. It has also been reported that FHV protein A replicates viral RNA in concert with the mitochondrial outer membrane and other viral or cellular factors and mediates the formation of viral RNA replication complexes and small spherules by inducing membrane rearrangement [PMID: 24466277].

This domain is also found in B1 proteins which are encoded by the subgenomic RNA3 during FHV replication. The function of translated B1 protein is poorly defined, but may be important for maintenance of RNA replication [PMID: 25318056].

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.