FIG. 6.

Analyses of the 191 core coexpressed with the WT or D219A mutant SPP. (A) 293T cells were cotransfected with the 191 core plasmid in the presence of pcDNA3, the WT, or D219A mutant SPP plasmid. Cell lysates were analyzed by Western blotting with the rabbit anti-core and HA MAb, respectively. (B) Postnuclear fractions from cells expressing the core alone or coexpressing the core and WT or mutant SPP were subjected to a membrane protection assay, followed by Western blotting with the HA MAb (top panel). The results from three individual studies were quantified, and the average values with the standard deviation are also shown (middle panel). Postnuclear fractions from cells transfected with the 191 core or D219A SPP mutant plasmid were analyzed by a proteinase K digestion assay (bottom panel).