CoV nsps play multiple roles in the synthesis or processing of viral RNA, or in virus-host interactions aiming to create an optimal environment for virus replication, such as facilitating viral entry, viral gene expression, RNA synthesis, and virion release. nsp1 is a N-terminal cleavage product of ORF1a polyprotein [71], a 9-kDa protein, that exists only in α-CoVs and β-CoVs [72].