Figure 1.

Generation of full-length clone of strain F with and without VP2 gene cassette. (A) Schematic representation of the construction of full-length clone pCI F1-F2-F3 of Newcastle disease virus (NDV) strain F. Assembly was carried out by sequential cloning of F1, F2 and F3 fragments into pCI vector. Fragment F1 contains hammerhead ribozyme (HHRz) at the 5′-end and fragment F3 contains hepatitis delta ribozyme (HdvRz) at the 3′-end. Restriction sites used for cloning are indicated. Abbreviations: CMV/T7, cytomegalovirus immediate-early enhancer and promoter/T7 RNA polymerase promoter; T7ɸ, T7 transcription termination. (B) Schematic representation of the NDV genome with the SacII and AvrII sites between the P and M genes and insertion of VP2 gene with HN signal between these sites.