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. 2020 Jul 14;11:1723. doi: 10.3389/fmicb.2020.01723

Figure 1.

Figure 1

Viral life cycle of SARS-CoV-2. Interaction between the S protein of SARS-CoV-2 and hACE2 initiates SARS-CoV-2 infection. Following receptor binding, the virus enters the cell by acid-dependent proteolytic cleavage of the S protein by TMPRSS2 or other proteases. Upon fusion of the viral and host cell membranes, viral genomic RNA is released in the cytoplasm. The viral RNA initiates translation of co-terminal polyproteins (pp1a/ab) by−1 frameshifting. These polyproteins are subsequently cleaved into nonstructural proteins (nsps) by Mpro and PLpro. Several nsp proteins interact with nsp12 (RdRp) to form the replicase-transcriptase complex (RTC), which is responsible for the synthesis of full-length viral genome (replication) and sub-genomic RNAs (transcription). The viral structural proteins are expressed and translocated into the endoplasmic reticulum (ER). The nucleocapsid (N) protein-encapsidated genomic RNA translocates with the structural proteins into the ER-Golgi intermediate compartment (ERGIC) for virion assembly. The newly synthesized virions are budded through the cell membrane and exocytosed.