Fig. 2.

Generation of molecularly cloned virus, BSD1, derived from a BAC cDNA clone, pBSD1. (A) Analysis of the in vitro transcripts synthesized from pBSD1 by denaturing agarose gel electrophoresis. Lane M shows molecular weight of the 1 kb RNA ladder (size indicated on the left), Lanes 1 and 2 show two independently-generated RNA molecules derived from pBSD1 by in vitro transcription with an expected size of ∼12.3 kb. (B) Detection of infectious virus. MDBK cells were treated with the supernatant from transfected cells or mock- or wt SD1-infected MDBK cells (set as negative and positive controls, respectively). Viral foci were visualized by immunoperoxidase staining at 72 h p.i.