FIG. 4.
Identification of MHV A59 ORF1a integral membrane proteins from infected-cell lysates treated with Triton X-114. HeLa-MHVR cells were infected with MHV A59, and proteins were metabolically labeled with Trans35S-label from 3.5 to 5.5 hpi. Cells were lysed in PBS containing 1% Triton X-114, and nuclei were removed by low-speed centrifugation. The cytosolic fraction was separated by centrifugation through a 6% (wt/vol) sucrose cushion as described in Materials and Methods. The detergent pellet fraction (P) and the soluble fraction (S) were subjected to immunoprecipitation with the indicated antisera. Products were analyzed as described for Fig. 1. Coprecipitating products are indicated by open arrowheads. Sizes are shown on the left in kilodaltons.