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. 2022 Feb 14;14(2):385. doi: 10.3390/v14020385

Figure 3.

Figure 3

Schematic of the SARS-CoV-2 replication cycle. Upon virus binding to the ACE-2 receptor, plus-strand genomic RNA is released in the cytoplasm, and subsequently translated into the two polyproteins pp1a and pp1ab, with expression of the latter depending on a programmed −1 ribosomal frameshift at the ORF1a/ORF1b overlap region. Then, pp1a and pp1ab are proteolytically cleaved to generate 16 non-structural proteins (nsps). Several of these proteins form the replication complex that drives the synthesis of minus-strand genomic RNA, which, in turn, is copied into new plus-strand genomic RNAs that can be packaged in new virions. Discontinuous transcription generates a set of 3′ co-terminal sub-genomic mRNAs with an identical 5′UTR (shown in orange) and 3′UTR (shown in blue). The sub-genomic RNAs are translated into structural and accessory proteins that will form the new virions. Assembly and budding of the virions take place at the ER-Golgi intermediate compartment (ERGIC). Nascent virions are released from the cell via exocytosis.