Figure 5. Solubility of GFP3A fusion proteins.

A) Distribution of fusion proteins in soluble or insoluble fractions of transfected cells. Vero cells transfected with 1 µg of pEGFP, pRSV3A and the plasmids expressing the fusion proteins indicated, were lysed in PBS buffer by freeze–thawing and fractionated by centrifugation. Proteins in pellets and supernatants were resolved on a 12% SDS-PAGE, transferred to a membrane, and blotted with MoAb to GFP or 3A (2C2). Statistically significant differences, relative to GFP3A are indicated by * (P≤0.05). B) Insoluble fraction association of transiently expressed GFP3A and GFP3ABBB proteins. Vero cells transfected with 1 µg of pEGFP3A or pEGFP3ABBB, were processed as in (A). Pellets were further treated with: Na₂CO₃, Urea, KCl or Triton X-100 (as described in Materials and Methods) and their proteins blotted with MoAb to GFP or to calnexin. Plots represent the percentage of the relative intensity of the protein bands in the blot that were quantified by densitometry with ImageJ program. Statistically significant differences, relative to PBS treatment, are indicated by * (P≤0.05).