FIG. 6.

Incorporation of 89.6G Env glycosylation mutants into VSV virions. BHK cells were infected with the indicated VSV recombinants at an MOI of 0.01 for 18 h. Cell debris was removed by centrifugation, and clarified supernatants were layered on top of a solution of 20% sucrose in TE buffer and centrifuged for 1 h at 4°C in a Beckman SW41 Ti rotor at 38,000 rpm. Western blotting to detect gp120 was performed by using sheep polyclonal anti-gp120 serum. Details of the Western blotting procedure are given in Materials and Methods. Molecular weight markers, as well as positions of cleaved and uncleaved Env G proteins, are indicated.