Mutation of an influenza virus polymerase 3′ RNA promoter binding site inhibits transcription elongation

Journal article

Influenza A virus encodes a viral RNA-dependent RNA polymerase (FluPol_A), which is responsible for transcribing and replicating the negative-sense viral RNA (vRNA) genome. FluPol_A transcribes vRNA using a host capped mRNA primer, and replicates it by synthesising a positive-sense complementary RNA (cRNA) intermediate which is copied back into vRNA. To carry out these functions, FluPol_A interacts with vRNA and cRNA using conserved promoter elements at the 5′ and 3′ termini. Recent structural studies have identified a new surface binding site for the 3′ vRNA and cRNA promoters on FluPol_A, referred to as the Mode B site. However, the role of this binding site in FluPol_A function is unknown. In this study we used a combination of cell-based and biochemical assays to show that the Mode B site is important for both viral genome transcription and replication. Furthermore, we show that the Mode B site is not needed for initiating transcription in vitro but is required to synthesise a full-length product. This is consistent with a model in which the 3′ terminus of the vRNA template binds in the Mode B site during elongation. Our data provide the first functional insights into the role of the Mode B site on FluPol_A, which advances our understanding of FluPol_A function and influenza A virus replication.

Authors: Walker, A; Sharps, J; Fodor, E

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: American Society for Microbiology
• Journal: Journal of Virology
• Volume: 94
• Article number: e00498-20
• Publication date: 2020-04-15
• Acceptance date: 2020-04-09
• DOI: 10.1128/JVI.00498-20
• EISSN: 1098-5514
• ISSN: 0022-538X
• Language: English
• Keywords: FFR