FIG. 2.
Analysis of the structures produced by BacΔIBDA. Sf9 cells were infected with BacΔIBDA and treated with Freon 113 as described in Materials and Methods. (A) After on 18-h centrifugation in CsCl at 100,000 × g, the gradient was illuminated with white light and photographed. (B and C) Material collected from the band present in the gradient was negatively stained with 1% uranyl acetate. Large numbers of tubules with an apparent diameter of 52 nm (B) and some icosahedral VLPs and tubules with a diameter of 25 nm (C) were observed. (D) The left panel shows SDS-PAGE analysis and Coomassie blue staining of purified IBDV (lane 1) and of the material isolated from the band present in the CsCl gradient (lane 2). The right panels show Western blot analyses of purified IBDV (lanes 1) and of the BacΔIBDA band present in the CsCl gradient (lanes 2) with an anti-pVP2/VP2 antibody or with an anti-VP3 antibody. The relative Mrs (in thousands) determined by reference to marker proteins are indicated on the left.