Advances in the development of infectious clones of human coronaviruses and related applications

Abstract

Coronaviruses can infect humans, mammals, and birds, leading to respiratory, gastrointestinal, and neurological diseases. These viruses are significant zoonotic pathogens with nine known types capable of infecting humans. The coronavirus genome, approximately 30 kb in size, is the largest known ribonucleic acid (RNA) virus genome, and its complexity makes assembly and manipulation time-consuming and labor-intensive. Reverse genetic systems are widely used to engineer recombinant viruses that can be adapted at Biosafety Level 2 (BSL-2) for studying viral gene function, replication, pathogenesis, vaccines, and therapeutics. The infectious clones, which enabled the recovery of various viruses after DNA recombinant technology, were indispensable tools for the reverse genetics of viruses. Various techniques for constructing infectious clones of human coronaviruses (HCoV) have been developed, encompassing methods such as vaccinia virus vectors method, in vitro ligation, bacterial artificial chromosome systems, yeast artificial chromosome systems, circular polymerase extension reaction, and the recently reported infectious sub-genomic amplicons technology. This review summarizes the status of various techniques for constructing infectious clones of human coronaviruses and related applications.