An Infectious cDNA Clone of SARS-CoV-2

Cell Host Microbe. 2020 May 13;27(5):841-848.e3. doi: 10.1016/j.chom.2020.04.004. Epub 2020 Apr 13.


The ongoing pandemic of COVID-19, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), underscores the urgency to develop experimental systems for studying this virus and identifying countermeasures. We report a reverse genetic system for SARS-CoV-2. Seven complimentary DNA (cDNA) fragments spanning the SARS-CoV-2 genome were assembled into a full-genome cDNA. RNA transcribed from the full-genome cDNA was highly infectious after electroporation into cells, producing 2.9 × 106 plaque-forming unit (PFU)/mL of virus. Compared with a clinical isolate, the infectious-clone-derived SARS-CoV-2 (icSARS-CoV-2) exhibited similar plaque morphology, viral RNA profile, and replication kinetics. Additionally, icSARS-CoV-2 retained engineered molecular markers and did not acquire other mutations. We generated a stable mNeonGreen SARS-CoV-2 (icSARS-CoV-2-mNG) by introducing this reporter gene into ORF7 of the viral genome. icSARS-CoV-2-mNG was successfully used to evaluate the antiviral activities of interferon (IFN). Collectively, the reverse genetic system and reporter virus provide key reagents to study SARS-CoV-2 and develop countermeasures.

Keywords: COVID-19; SARS-CoV; SARS-CoV-2; antiviral; coronavirus; vaccine.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Antiviral Agents / therapeutic use
  • Betacoronavirus / genetics*
  • Betacoronavirus / pathogenicity*
  • COVID-19
  • Chlorocebus aethiops
  • Clone Cells
  • Coronavirus Infections / drug therapy
  • Coronavirus Infections / virology*
  • DNA, Complementary / genetics*
  • Genes, Reporter / genetics
  • Genome, Viral / genetics
  • Interferons / therapeutic use
  • Organisms, Genetically Modified / genetics*
  • Organisms, Genetically Modified / pathogenicity*
  • Pandemics
  • Pneumonia, Viral / drug therapy
  • Pneumonia, Viral / virology*
  • RNA, Viral / genetics
  • SARS-CoV-2
  • Vero Cells / virology
  • Virus Replication / physiology


  • Antiviral Agents
  • DNA, Complementary
  • RNA, Viral
  • Interferons