GSE162629
A novel cell culture system modeling the SARS-CoV-2 life cycle
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes the global pandemic of COVID-19, and no effective antiviral agents and vaccines are available. SARS-CoV-2 is classified as a biosafety level-3 (BLS-3) agent, impeding the basic research into its biology and the development of effective antivirals. Here, we described a safe cell culture system for production of transcription and replication-competent, biologically contained SARS-CoV-2 virus like particles (trVLP) that express a reporter gene (GFP) replacing viral nucleocapsid gene, which is required for viral genome packaging and virion assembly (SARS-CoV-2-GFP/?N trVLP). The complete viral life cycle can be exclusively achieved and confined in the cells expressing SARS-CoV or SARS-CoV-2 N proteins in trans, but not MERS-CoV N. Additionally, genetic recombination of N supplied in trans into viral genome was not detected, as evidenced by sequence analysis after one-month serial passages in N-expressing Caco-2 cells. Moreover, Intein-mediated protein trans-splicing approach was utilized to split the viral N gene into two independent vectors, and the ligated viral N protein could function in trans to recapitulate entire viral life cycle, further securing the biosafety of this cell culture model. To prove the suitability of this system in antivirals discovery, we developed a 96-well format high throughput screening to identify salinomycin, monensin sodium and lycorine chloride exhibiting potent antiviral activities against SARS-CoV-2 infection. Collectively, we propose that this cell culture system based on Intein-N genetic complementation to produce SARS-CoV-2 trVLP provides a safe means to dissect the virus life cycle, and thus accelerate our understanding of virus biology, as well as for more applied uses such as the screening and development of novel antivirals, and thus represent powerful tools for SARS-CoV-2 study. Overall design: Caco-2 cells infected with SARS-CoV-2 GFP delN P1 or P10 virus are used for RNA-seq