The P323L substitution in the SARS-CoV-2 polymerase (NSP12) confers a selective advantage during infection
Hannah Goldswain, Xiaofeng Dong, Rebekah Penrice-Randal, Muhannad Alruwaili, Ghada T. Shawli, Tessa Prince, Maia Kavanagh Williamson, Jayna Raghwani, Nadine Randle, Benjamin Jones, I’ah Donovan-Banfield, Francisco J. Salguero, Julia A. Tree, Yper Hall, Catherine Hartley, Maximilian Erdmann, James Bazire, Tuksin Jearanaiwitayakul, Malcolm G. Semple, Peter Openshaw, J. Kenneth Baillie, ISARIC4C Investigators, J. Kenneth Baillie, Malcolm G. Semple, Peter Openshaw, Gail Carson, Beatrice Alex, Petros Andrikopoulos, Benjamin Bach, William Barclay, Debby Bogaert, Meera Chand, Kanta Chechi, G Cooke, Ana da Silva Filipe, Thushan I. de Silva, Annemarie B Docherty, Gonçalo dos Santos Correia, Marc‐Emmanuel Dumas, Jake Dunning, Tom Fletcher, Chris Green, William Greenhalf, Julian L. Griffin, Rishi K Gupta, Ewen M. Harrison, Julian A. Hiscox, Antonia Ho, Peter W Horby, Samreen Ijaz, Saye Khoo, Paul Klenerman, Andrew Law, Matthew R. Lewis, Sonia Liggi, Wei Shen Lim, Lynn Maslen, Alexander J. Mentzer, Laura Merson, Alison M Meynert, Shona C. Moore, Mahdad Noursadeghi, Michael Olanipekun, Anthonia Osagie, Massimo Palmarini, Carlo Palmieri, William A. Paxton, Georgios Pollakis, Nicholas Price, Andrew Rambaut, David L. Robertson, Clark D Russell, Vanessa Sancho‐Shimizu, Caroline Sands, J T Scott, Louise Sigfrid, Tom Solomon, Shiranee Sriskandan, David I. Stuart, Charlotte Summers, Olivia Swann, Zoltán Takáts, Panteleimon G. Takis, Richard S. Tedder, A. A. Roger Thompson, Emma C. Thomson, Ryan S. Thwaites, Lance Turtle, Maria Zambon, Hayley Hardwick, Chloe Donohue, Fiona Griffiths, Wilna Oosthuyzen, Cara Donegan, Rebecca G. Spencer, Lisa Norman, Riinu Pius, Thomas M Drake, Cameron J. Fairfield, Stephen R Knight
Abstract
BACKGROUND: The mutational landscape of SARS-CoV-2 varies at the dominant viral genome sequence and minor genomic variant population. During the COVID-19 pandemic, an early substitution in the genome was the D614G change in the spike protein, associated with an increase in transmissibility. Genomes with D614G are accompanied by a P323L substitution in the viral polymerase (NSP12). However, P323L is not thought to be under strong selective pressure. RESULTS: Investigation of P323L/D614G substitutions in the population shows rapid emergence during the containment phase and early surge phase during the first wave. These substitutions emerge from minor genomic variants which become dominant viral genome sequence. This is investigated in vivo and in vitro using SARS-CoV-2 with P323 and D614 in the dominant genome sequence and L323 and G614 in the minor variant population. During infection, there is rapid selection of L323 into the dominant viral genome sequence but not G614. Reverse genetics is used to create two viruses (either P323 or L323) with the same genetic background. L323 shows greater abundance of viral RNA and proteins and a smaller plaque morphology than P323. CONCLUSIONS: These data suggest that P323L is an important contribution in the emergence of variants with transmission advantages. Sequence analysis of viral populations suggests it may be possible to predict the emergence of a new variant based on tracking the frequency of minor variant genomes. The ability to predict an emerging variant of SARS-CoV-2 in the global landscape may aid in the evaluation of medical countermeasures and non-pharmaceutical interventions.