SARS-CoV-2 structure and replication characterized by in situ cryo-electron tomography

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of the COVID19 pandemic, is a highly pathogenic β-coronavirus. As other coronaviruses, SARS-CoV-2 is enveloped and remodels intracellular membranes for genome replication and assembly. Here, we report critical insights into the budding mechanism of the virus and provide structural details of virions and virus induced double-membrane vesicles by in situ cryo-electron tomography. We directly visualized double-stranded RNA within double-membrane vesicles, forming a loosely organized network with frequent RNA branching consistent with template-directed RNA synthesis intermediates. Our data indicate that membrane bending is orchestrated by the spike trimer and viral ribonucleoprotein complex recruitment into virion budding sites, suggesting the synergistic interplay of both viral components as a possible drug target for intervention.