Figure 1.

Generation of recombinant viruses. (A) Overview of the MDV genome and the recombinant BAC clones. The MDV genome consists of a unique long and short region (U_L and U_S) flanked by the terminal repeat long and short (TR_L, TR_S) and the internal repeat long and short (IR_L, IR_S). The a–like sequences harboring the cleavage and packaging signals are indicated. The recombinant viruses were generated based in the ΔIR_LΔIR_S BAC lacking most of the IR_L and IR_S region, which is rapidly restored upon reconstitution. TetR-GFP is depicted in dark green, tetO sequence in blue, GFP in light green, and E2-Crimson in red; (B) RFLP of indicated recombinant BAC genomes using NdeI; (C) Southern blot of the same RFLP gel using a specific TetO probe to confirm the presence and length of the tetO sequences in the virus genome.