Fig. 1

MA-SARS2 spike grants mouse infectivity A Schematic illustration of mutations in the spike protein of mouse-adapted strains containing N501Y. NTD (brown): N terminus domain; RBD (blue): receptor-binding domain; SD (yellow): subdomain; S2 (gray): subunit 2. B Top (left) and side (right) view of S glycoprotein of mouse-adapted strains. Spheres represent mutations, brown: Ins215KLRS, blue: N501Y, yellow: H655Y, gray: other mutations in RBD. C Representative images of syncytia formation upon expression of the indicated S glycoprotein in 293T cells expressing human ACE2 (hACE2) and mouse ACE2 (mACE2). Bar: 100 μm. D Quantification of syncytia formation. Data are the mean ± SD of results from 4 fields (10× objective lens). More than three replicates were performed. E Expression of the luciferase reporter in 293T-hACE2 and 293T-mACE2 cells upon infection of viruses pseudotyped with Wild type or MA-SARS2 S glycoproteins. Data are the mean ± SD of triplicate measurements