Fig. 1.

Life cycle of coronavirus. (A) ACE-2-mediated entry of corona virus via endocytosis, followed by uncoating and synthesis of polyprotein 1a (pp1a) and pp1ab using genomic RNA (+ve) strand. Proteolysis of polyproteins with the help of host lysosomal proteases to make nonstructural protein RNA-dependent RNA polymerase (RdRP) that uses (+ve) strand genomic RNA as a template. The (+ve) strand genomic RNA is synthesized by the process of replication becomes the genome of the new virus particles. The transcription of (–ve) strand into subgenomic RNAs that are translated into structural proteins. Reassembly of viral particles in RER and secreted via Golgi vesicles as new viruses by exocytosis.