FIG. 6.
Membrane integration of deletion mutant forms of MHV nsp6. (A) Schematic representation of the MHV nsp6 C-terminal deletion mutant forms, with the hydrophobic domains presented in black and the EGFPglyc tag in gray. (B) vTF7-3-infected OST7-1 cells were transfected with the constructs presented in panel A and expressed in the presence (+) or absence (−) of tunicamycin (TM). The cells were labeled with [35S]methionine from 5 to 6 h p.i., lysed, and processed for immunoprecipitation with anti-EGFP antiserum, followed by SDS-PAGE. The positions and masses (in kilodaltons) of the protein size markers are indicated at the left. The asterisks indicate the positions of the glycosylated protein species. Below the gel, the observed presence or absence of N glycosylation is indicated by a plus or a minus sign, respectively. (C) Models of the membrane structures of the C-terminal deletion mutant forms of MHV nsp6. The hydrophobic domains are presented as black rectangles, and the EGFP tag is presented as a dark gray rectangle when glycosylated and in light gray when unglycosylated.