Understanding Human Coronavirus HCoV-NL63

Abdul-Rasool, Sahar; Fielding, Burtram C

HCoV-NL63 ORF1a/1b contains a putative elaborated pseudoknot structure that triggers a -1 ribosomal frameshift to translate the complete 1ab polyprotein; for a mini-review of the putative ORF1a/1b products and functions see Pryc et al. (2007) [27] and Van der Hoek et al. (2006) [8] . Chen and colleagues identified processed products nsp3 and nsp4 of the HCoV-NL63 replicase polyprotein, which could be detected at 24 hours post-infection. These products localize in the peri-nuclear sites of virus infected cells. Also, the group identified and characterized two viral papain-like proteases, PLP1 and PLP2, which process the viral replicase polyprotein. Interestingly, the PLP2 protease has deubiquitinating activity [9] , although the function of this is not clear in viral replication.