Fig. 2: DNA- and RNA-launched viruses replicate similarly to virus derived from patient isolate.

A Schematic of virus rescue from RNA or DNA. For RNA-launched virus rescue, in vitro transcribed RNA from viral construct (pBAC SARS-CoV-2) and N expression construct (pN) is electroporated into BHK-21 cells followed by co-culture with Vero ACE2 TMPRSS2 (Vero AT) cells to yield p0 viral stock, which is propagated in the same cells onward. For DNA-launched virus rescue, pBAC SARS-CoV-2 and pN are directly transfected into BHK-21 cells to yield p0 viral stock, which is then propagated in Vero AT cells. B Plaque morphology of DNA- and RNA-launched and patient-derived Delta variant viruses. Images were pseudocolored to black and white for optimal visualization. The images represent three independent replicate experiments. C Growth kinetics of the viruses in B in Vero TMPRSS2 and Calu3 cells over 72 h as measured by infectious particle release by plaque assay. Average of three independent experiments analyzed in duplicate ± SD is shown. D Replication of the viruses in B was assessed in K18-hACE2 mice lungs at 48 h post-infection by infectious particle release by plaque assay and viral RNA by RT-qPCR. Data are presented as average ± SD of 3 mice in each group. Source data are provided as a Source Data file.