Method: A plasmid expressing the SARS-CoV-2
S D614G/
P681R mutant was generated by site-directed mutagenesis PCR using pC-SARS2-
S D614G as the template and the following primers:
P681R Fw, 5'-CCAGACCAACAGCCGGAGGAGGGCAAGGTCT-3' and
P681R Rv, 5'-AGACCTTGCCCTCCTCCGGCTGTTGGTCTGG-3'.
Method: For virological examinations, four hamsters per group were intranasally infected with the
D614G or the
D614G/
P681R viruses (104 TCID50 in 30 mul); at 3 and 7 d.p.i., the hamsters were euthanized, and nasal turbinates and lungs were collected.