Figure 1: Biotinylation and Qdot labeling of SINV. SINV was labeled with NHS PEG4-biotin as described in Section 2. (a) Western blot analysis of biotinylated SINV using alkaline-phosphatase-conjugated streptavidin showing efficient labeling of the E1/E2 envelope proteins (indicated by *). Lanes 1: control unlabeled SINV and 2: biotinylated SINV. Molecular weight markers (kD) are labeled. (b) Biotinylated SINV labeled with Qdot 605 specifically bound target cells. Arrows indicate Qdot-labeled SINV. Bar = 25 μm. (c) Biotinylated SINV labeled with Qdot 605 was active infecting target cells and expressing GFP. Images were taken 14 hours after infection. Arrowheads indicate Qdot signals. Bar = 25 μm.