Fig. 6

Confirmation of host factor involvement by targeted shRNA knockdown and CRISPR knockout. Lentivirus-packaged shRNA clones directed to CTSL, CCZ1, and EDC4 were transduced into HEK293T-hACE2 cells and selected with puromycin. Lentivirus-packaged sgRNA directed to EDC4 and XRN1 were transduced into SAEC-hACE2 cells and selected with puromycin. A Gene knockdown was assessed using western blotting with antibodies directed to CTSL, CCZ1, and EDC4 in cells transduced with a gene-specific shRNA or empty vector control (EV). Actin expression served as a loading control. B Triplicate wells of knockdown cells were infected with SARS-CoV-2 or OC43 at MOI 0.01. At 2 dpi, viral genome copy numbers were determined by RT-qPCR and normalized to GAPDH levels as a housekeeping control. The data are reported as the relative normalized viral genome copy number in shRNA-expressing cells compared to the EV control (n = 3 experiments). Error bars denote standard errors of mean and P values were determined using one-way ANOVA (*P < 0.05, **P < 0.01, ***P < 0.001). C EDC4 and XRN1 knockout in SAEC-hACE2 was assessed using western blotting with antibodies directed to EDC4 and XRN1 in cells transduced with a gene-specific sgRNA or in wild-type cells (WT). Actin expression served as a loading control. D Triplicate wells of SAEChACE2 WT, EDC4ko, and XRN1ko cells were infected with SARS-CoV-2 or OC43 and MOI 0.01. At 0hpi, 1dpi, 2dpi, and 3dpi, cell supernatants were harvested and infectious viral particles were measured by TCID50 (n = 2 experiments). Error bars denote standard errors of mean and P values were determined using one-way ANOVA (*P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001)