Effects of arginine-13, lysine-72, and serine-177 mutations of S-HDAg on HDV genomic and antigenomic RNA synthesis. (A and B) The wild-type HDV genomic RNA (A) or antigenomic RNA (B) was transfected together with the S-HDAg-encoding defective mutant (d1nt) or with S-HDAg mRNAs encoding the wild-type (WT) S-HDAg or R13A, K72A, or S177A S-HDAg mutant into Huh7 cells. (C and D) Alternatively, the HDV genomic RNA (C) or antigenomic RNA (D) encoding the wild-type (WT) or R13A, K72A, or S177A HDAg was transfected together with the corresponding S-HDAg mRNA encoding the same mutation. At day 6 posttransfection, total RNAs were extracted, and HDV antigenomic RNA (A and C) and genomic RNA (B and D) were detected by qRT-PCR using the AG-S and G-S protocols, respectively (Table 2). The data were normalized relative to the values detected in the wild-type HDV RNA transfection. Error bars indicate standard deviations. G + m#, wild-type genomic RNA cotransfected with mutant mRNA; AG + m#, wild-type antigenomic RNA cotransfected with mutant mRNA; G# + m#, mutant genomic RNA cotransfected with mutant mRNA; AG# + m#, mutant antigenomic RNA cotransfected with mutant mRNA.