Identification of DAXX as a restriction factor of SARS-CoV-2 through a CRISPR/Cas9 screen
Alice Mac Kain, Ghizlane Maarifi, Sophie‐Marie Aicher, Nathalie J. Arhel, Artem Baidaliuk, Sandie Munier, Flora Donati, Thomas Vallet, Quang Tran, Alexandra Hardy, Maxime Chazal, Françoise Porrot, Molly OhAinle, Jared Carlson-Stevermer, Jennifer Oki, Kevin Holden, Gert Zimmer, Etienne Simon‐Lorière, Timothée Bruel, Olivier Schwartz, Sylvie van der Werf, Nolwenn Jouvenet, Sébastien Nisole, Marco Vignuzzi, Ferdinand Roesch
Abstract
Interferon restricts SARS-CoV-2 replication in cell culture, but only a handful of Interferon Stimulated Genes with antiviral activity against SARS-CoV-2 have been identified. Here, we describe a functional CRISPR/Cas9 screen aiming at identifying SARS-CoV-2 restriction factors. We identify DAXX, a scaffold protein residing in PML nuclear bodies known to limit the replication of DNA viruses and retroviruses, as a potent inhibitor of SARS-CoV-2 and SARS-CoV replication in human cells. Basal expression of DAXX is sufficient to limit the replication of SARS-CoV-2, and DAXX over-expression further restricts infection. DAXX restricts an early, post-entry step of the SARS-CoV-2 life cycle. DAXX-mediated restriction of SARS-CoV-2 is independent of the SUMOylation pathway but dependent on its D/E domain, also necessary for its protein-folding activity. SARS-CoV-2 infection triggers the re-localization of DAXX to cytoplasmic sites and promotes its degradation. Mechanistically, this process is mediated by the viral papain-like protease (PLpro) and the proteasome. Together, these results demonstrate that DAXX restricts SARS-CoV-2, which in turn has evolved a mechanism to counteract its action.