Fig. 1.

Diagram of BAC cDNA clone pBSD1, including restriction sites for subcloning, sequences surrounding engineered run-off and transcription initiation sites, and introduced genetic markers. The genome of BVDV SD1 is 12,308 nt in length including a 5′-untranslated region (UTR) of 385 nt, a large ORF of 11,697 nt, and a 3′-UTR of 226 nt. pBSD1 with the SD1 cDNA insertion and viral protein positions in the viral polyprotein sequence are indicated approximately to scale. The additional inserted sequences shown below the bar include: the T7 promoter sequence (lowercase, underlined), the T7 transcription start site (arrow), the 5′- and 3′- terminal SD1 cDNA sequences (positive sense, uppercase), engineered run-off restriction site of SdaI (bold, uppercase, underlined), and subcloning restriction sites of XbaI, PacI, and FseI (bold, uppercase, italic). The position of the five silent point mutations employed as genetic markers are indicated noting nucleotide position: T7575C, G7882C, G9022A, A10192G, and A12264G.