CHARACTERIZATION OF THE GENES, INCLUDING THAT ENCODING THE VIRAL PROTEINASE, CONTAINED IN BAMHI RESTRICTION FRAGMENT-9 OF THE PSEUDORABIES VIRUS GENOME

We describe the nucleotide sequence, transcription pattern and open re ading frames (ORFs) located on BamHI restriction fragment 9 (0 . 406-0 . 435 map units) in the unique long segment of the pseudorabies virus (PRV) genome, The fragment contains three nested genes with a common 3' end, The 5' ends of the corresponding 0 . 9, 1 . 7 and 3 . 3 kb mRN As have been mapped, Fragment BamHI-9 contains three complete ORFs, OR F1, ORF2 and ORF2.5. ORF1, which is within the 3 . 3 kb transcript, en codes a protein with an apparent molecular mass of 60 kDa which is hom ologous to the product of the herpes simplex virus type 1 UL25 gene, T he 1 . 7 kb mRNA contains ORF2, whose product is homologous to the her pesvirus proteinases, while the 0 . 9 kb transcript contains ORF2.5, w hich probably encodes the assembly protein precursor, ORF2 was identif ied as the PRV proteinase gene following expression in E. coli, using the product of ORF2.5 as the substrate protein.