Fig. 2.

Replication of coronaviruses: [1] The Spike protein on the SARS-CoV-2 binds to ACE2, a protease TMPRSS2 promotes fusion and entry of the virion into the host cell. [2] The virus releases positive-stranded RNA into the cytoplasm [3] RNA is translated in viral replicase complex to synthesize more copies of RNA. [4] The polymerase produces many subgenomic RNA by discontinuous transcription and some of these encode for structural proteins N, S, E and M. [5] The structural proteins S, E, and M are translated and inserted into endoplasm reticulum. [6] The viral structural protein, genomic RNA and N protein are assembled into virions by budding into the lumen of the ERGIC (endoplasmic reticulum (ER)–Golgi intermediate compartment). [7] Following the assembly, the virions are transported to the cell surface in vesicles and released via exocytosis.