English: Flock house virus genome organization and functional map of replicase protein A. (A) The bipartite FHV RNA genome encodes the viral replicase protein A on RNA1 and the capsid protein precursor on RNA2. Protein A mediates synthesis of a negative strand copy of the genomic RNAs which serves as template for synthesis of progeny positive strand RNAs, and an additional partial negative strand copy of RNA1 to template a 3’ co-terminal subgenomic RNA3. RNA3 potentially encodes protein B1, co-terminal with the C-terminus of protein A, and protein B2 which has anti-RNAi function. (B) A linear representation of protein A annotated to show membrane-association and enzymatic domains, and several regions independently capable of homotypic multimerization.