FIG 1.

Stability analysis of the vaccine virus strain and complementing cell line. (A) Genomic RNA profile of the BTV1 DISC strain in complementing BS9 cells at passages 5 (P5) and 10 (P10). WT, BTV1 control. Positions of RNA segments (S1 to S10) are indicated. (B) Sequence electropherograms of S9 RT-PCR products from passages 5 and 10. Mutations in S9 are underlined, and the sequence of the WT virus is shown. (C) Expression of VP6 in the complementing BS9 cell line in the presence (+ Puro) or absence (− Puro) of puromycin at passages 17, 20, and 23 by Western blotting. Lane C, normal BSR cells; lane M, protein marker.