Nucleotide requirements at positions +1 to +4 for the initiation of hepatitis C virus positive-strand RNA synthesis Nandasoma, Udvitha and McCormick, Christopher and Griffin, Stephen and Harris, Mark,, 92, 1082-1086 (2011), doi = https://doi.org/10.1099/vir.0.028423-0, publicationName = Microbiology Society, issn = 0022-1317, abstract= RNA virus genome replication requires initiation at the precise terminus of the template RNA. To investigate the nucleotide requirements for initiation of hepatitis C virus (HCV) positive-strand RNA replication, a hammerhead ribozyme was inserted at the 5′ end of an HCV subgenomic replicon, allowing the generation of replicons with all four possible nucleotides at position 1. This analysis revealed a preference for a purine nucleotide at this position for initiation of RNA replication. The sequence requirements at positions 2–4 in the context of the J6/JFH-1 virus were also examined by selecting replication-competent virus from a pool containing randomized residues at these positions. There was strong selection for both the wild-type cytosine at position 2, and the wild-type sequence at positions 2–4 (CCU). An adenine residue was well tolerated at positions 3 and 4, which suggests that efficient RNA replication is less dependent on these residues., language=, type=