FIG. 7.

Pleiotropic roles of nsp10 in CoV replication. (A) After translation, pp1a and pp1ab are processed into precursors and mature proteins. nsp10 appears to influence processing in mutant nsp10-E2, which shows evidence of processing intermediates not seen in wt-icMHV. These data suggest that nsp10 likely interacts with another nsp to facilitate cleavage or maintains a structure that allows the polyprotein to fold into the proper orientation for 3CLpro activation. (B) Once processed, nsp10 functions in replication, probably as a dimer or trimer that binds RNA and nsp7. Our mutant panel suggests that nsp10 may function in both the negative- and positive-strand replicases. The numbers in the diagram represent nsp numbers. The dotted line represents RNA. The curved line represents the double-membrane structure.