Figure 3

Purification and characterization of FLAG-inserted DENV-LPs. (a) FLAG-inserted DENV-2 VLP was purified by utilizing magnetic beads conjugated with the anti-FLAG antibody. Aliquots of crude culture supernatant from FL-273-expressing cells (Sup), washing buffer used after VLP-beads binding (W) and eluate from the VLP-bound beads (Elu) were separated by SDS-PAGE, followed by CBB staining (left) and western blotting with anti-E protein antibody (upper light) and anti-FLAG antibody (lower right). (b) The density of DENV-LP was determined by sucrose density gradient centrifugation. Aliquots of each fraction (Fr.1–11) were analyzed by SDS-PAGE and western blotting. (c) Purified FLAG-inserted VLPs derived from DENV-1, -2, -3 and -4 analyzed by SDS-PAGE and CBB staining. Uncropped images of western blotting and CBB staining pictures in Fig. 3 are included in supplementary Fig. 3. (d) DENV-2 VLP samples were stained with uranyl acetate solution and observed by TEM. The scale bar shows the length of 50 nm.