Fig. 5.

Electron micrographs of BHK-21 cells transfected with pCAG-CprME. The BHK-21 cells were transfected with pCAG-CprME or optimal medium as negative control. The cells were then trypsinized at 24 and 72 hours post-transfection (hpt), centrifuged and after supernatant removal they were resuspended in a fixative solution (2.5% v/v glutaraldehyde in 0.1 M phosphate buffer [pH 7.4]), and sent for electron microscopy examination. (A and B) Spherical tick-borne encephalitis virus viral-like particles (TBE VLP) (50 nm in diameter) were observed in the lumen of membrane-bound vesicles at (A) 24 hpt and (B) also at 72 hpt. (B) pCAG-CprME-transfected cells. (C) A possible premature TBE VLP (indicated by a white arrow) in the lumen of rough endoplasmic reticulum (rER) accumulation of the C proteins (indicated by a white arrow) at (D) the cytosolic face of membrane-bound vesicles (E) as well as inside cytoplasm and (F) highly proliferating rER (indicated by star) were observed in the pCAG-CprME-transfected cells. (G and H) The COS-1 cells were transfected with optimal medium as negative control compared with pCAG-CprME-transfected cells at 72 hpt. The VLPs and membrane-bound vesicles are indicated by black arrow and triangles, respectively. The scale bar for each image is also shown. Nu = nucleus; Mito = mitochondria; GA = Golgi apparatus; TGN = trans-Golgi network; CI = clathrin-coated vesicle; Co, COP-coated vesicle; COP, coat protein complex.