Sequence and transcriptional analysis of a near-terminal region of the orf virus genome.

A 3605 bp region located approximately 6.6 kb from the left end of the orf virus genome (strain NZ2) was sequenced. The sequence revealed two open reading frames, which we have designated G2L and B1L. The predicted amino acid sequences of G2L and B1L were found to be homologous to the vaccinia virus (VAC) F11L and F12L gene products, respectively, and were found to be arranged on the genome in the same orientation and relative position as their VAC counterparts. Transcriptional analysis of both G2L and B1L showed they were transcribed toward the genome terminus during the early phase of infection. S1 nuclease and primer-extension analyses showed that the transcriptional start sites of both genes were located a short distance downstream from A+T-rich sequences, similar to vac virus early promoters.