Fig. 1.

Incorporation of fluorescent fusion proteins into extracellular viral particles. Western blots of proteins from purified extracellular viral particles electrophoresed through 7.5% SDS/polyacrylamide (A) or 4–15% gradient SDS/polyacrylamide gels (B) are shown. Blots were probed with an anti-GFP antibody and, in one case, reprobed with an anti-FLAG antibody (A; FLAG-VP1/2 lane in image at right resulted from reprobing indicated lane in left image). Viruses expressing GFP-VP1/2 alone or in combination with mRFP1-VP26 showed similar GFP-VP1/2 incorporation. (C) Illustration depicting method used to image newly released fluorescent viral particles from cells transfected with recombinant herpesvirus DNA. (D) Imaging of individual diffraction-limited fluorescent virions, as illustrated in C, at 2 d posttransfection. Labels at the left indicate the GFP fusion present in each sample, and the percentages at the right indicate the fraction of mRFP1 particles that also emit GFP fluorescence. All images are 10 μm × 10 μm.