Schematic overview of plasmids containing the full-length BTV genome segment. A full-length BTV genome segment flanked by a T7 promoter and a BsmBI (for S10) or BbsI (for S7) restriction enzyme site which defines the BTV 3'end sequence during transcription. The nucleotides of the ultimate 5'- and 3'-ends of the BTV genome segment are presented in bold symbols. The sequence of the T7 promoter is italicized, and the BsmBI site is underlined. The positions of the start of transcription and digestion by restriction enzymes for run-off transcription are indicated by arrows.