Figure 6.

^CtmPrP is retained in the ER. (A and B) Transfected BHK cells expressing FLAG-wild-type PrP (A) or FLAG-L9R/3AV PrP (B) were stained with 3F4 antibody without permeabilization to visualize PrP on the cell surface. The faint staining visible in B represents background, because it is also seen on untransfected cells (not shown). (C–H) Transfected CHO cells were fixed, permeabilized, and stained with antibodies to PrP (P45-66) and protein disulfide isomerase. After treatment with secondary antibodies, cells were viewed by laser scanning confocal microscopy to visualize PrP (green, C and F) or protein disulfide isomerase (red, D and G). E and H show a merge of the PrP and protein disulfide isomerase staining patterns. The punctate intracellular staining for PrP seen in C and E colocalizes with a Golgi marker (data not shown). Bars, 25 μm.