Coronaviruses belong to the order Nidovirales in the family coronaviridae.20 The N protein attaches to the viral genome and is involved in RNA replication, virion formation and immune evasion.The length of the SARS-CoV-2 genome is less than 30 kb, in which there are 14 open reading frames (ORFs), encoding non-structural proteins (NSPs) for virus replication and assembly processes, structural proteins including spike (S), envelope (E), membrane/matrix (M) and nucleocapsid (N), and accessory proteins.18 , 19 The S protein is a transmembrane protein that facilitates the binding of viral envelop to angiotensin-converting enzyme 2 (ACE2) receptors expressed on host cell surfaces.16 , 17 The first ORF contains approximately 65% of the viral genome and translates into either polyprotein pp1a (nsp1-11) or pp1ab (nsp1-16).Similar to other coronaviruses, the genome of SARS-CoV-2 is positive-sense single-stranded RNA [(+) ssRNA] with a 5?-cap, 3'-UTR poly(A) tail.