FIG. 4.

Effect of reversions and second-site mutations in the prM signal sequence on the efficiency of cleavage of prM in cell-free translation assays. Cell-free translation of YFV structural proteins was performed in the presence of microsomal membranes with appropriate RNA transcripts derived from plasmids pYF.s, pYF.VPQAQA, pYF.V2(P₁₁₇→L), pYF.V4(H₁₀₃→L), and pYF.V7(T₁₀₇→I). Immunoprecipitation was performed with anti-YFV hyperimmune ascitic fluid, and proteins were separated by SDS-PAGE (12% acrylamide). Bands corresponding to YFV proteins E and prM are labeled on right.