An infectious cDNA clone of SARS-CoV-2

 The reverse genetics system that is available for artificially generation of recombinant SARS-CoV-2 was established. The approximately 30,000 nucleotide length SARS-CoV-2 genome was divided into seven fragments cDNA, which were connected by DNA direct ligation using unique restricted enzymes BsaI and Esp3I. The resultant RNA product with poly (A) tail transcripted by a T7 RNA polymerase combined with cap analog was electroporated into Vero E6 cells. Four days posttransfection, infectious viruses were obtained. The authors also reported that a fluorescent gene mNeonGreen inserted into ORF7 was active as the reporter marker, which can facilitate the study to screen antiviral inhibitors against SARS-CoV-2.