The current COVID-19 pandemic is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with new variants continuously emerging. Since the beginning of pandemic, we set up PC3 facilities dedicated to SARS-CoV-2 work at the UQ’s School of Chemistry and Molecular Biosciences and established a range of productive collaborations on various projects including viral detection assays, virus inactivation, and development of vaccines and antivirals (e.g.1-4).  

SARS-CoV-2 is a positive strand RNA virus with a large ~30kb genome. The ability to manipulate SARS-CoV-2 genome allows to assess the role of changes present in different viral variants on various virus properties including their susceptibility to immune responses elicited by vaccinations. We have developed a circular polymerase extension reaction (CPER) methodology for in vitro assembly of full-length SARS-CoV-2 cDNA that does not require intermediate steps of cloning in bacteria and in vitro RNA transcription (5). Overlapping cDNA fragments are generated from viral RNA and assembled together with a linker fragment containing mammalian expression promoter into a circular full-length cDNA. Transfection of this cDNA into mammalian cells results in the recovery of SARS-CoV-2 virus that exhibits properties comparable to the parental virus in vitro and in vivo. We have applied CPER to generate SARS-CoV-2 variants, recombinants, and reporter viruses and are employing them for studies on virus replication and virus-host interactions.