GENOME ORGANIZATION AND TRANSCRIPTION STRATEGY IN THE COMPLEX G(NS)-LINTERGENIC REGION OF BOVINE EPHEMERAL FEVER RHABDOVIRUS

A 1622 nucleotide region of the bovine ephemeral fever virus (BEFV) ge nome, located between the second glycoprotein (G(MS)) gene and the pol ymerase (L) gene, has been cloned and sequenced in Australian (B87721) and Chinese (Beijing-1) isolates of the virus, In the Australian isol ate, the region contains five long open reading frames (ORFs) organize d into three coding regions (alpha, beta and gamma), each of which are bound by a consensus transcription initiation and transcription termi nation-polyadenylation-like sequences. The alpha coding region contain s three long ORFs (alpha 1, alpha 2 and alpha 3). The alpha 1 ORF enco des a 10.6 kDa polypeptide which contains hydrophobic and highly basic regions characteristic of a viroporin. The alpha 2 ORF encodes a 13.7 kDa polypeptide and overlaps the alpha 3 ORF which encodes a 5.7 kDa polypeptide. The beta coding region contains a single long ORF encodin g a polypeptide of 12.2 kDa, The gamma coding region, which does not o ccur in Adelaide River virus (ARV), contains a single long ORF encodin g a polypeptide of 13.4 kDa, The Chinese isolate shares 91% nucleotide sequence identity with the Australian isolate, The organization of th e alpha, beta and gamma coding regions is preserved and the sequences of the encoded polypeptides are similar to those of BB7721. The major transcription products of the region were identified in BB7721 as poly cistronic a (alpha 1-alpha 2-alpha 3) and beta-gamma mRNAs, Sequence s imilarities in the BEFV alpha-beta and beta-gamma gene junctions, and the gamma-L and beta-L gene junctions of BEFV and ARV, suggest that th e gamma gene may have evolved from the beta-gene by sequence duplicati on.