CHARACTERIZATION OF THE BOVINE HERPESVIRUS-1 HOMOLOG OF THE HERPES-SIMPLEX VIRUS-1 UL24 OPEN READING FRAME

An open reading frame (ORF) of 293 codons which partially overlaps the bovine herpesvirus 1 (BHV1) thymidine kinase (tk) ORF in a head-to-he ad orientation has been identified by nucleotide sequence analysis. Th e predicted amino acid sequence of this ORF exhibits an overall identi ty of 38.1% with that of the herpes simplex virus type 1 (HSV1) UL24 O RF as well as an 80.7% identity with the 57-amino-acid consensus seque nce found in the UL24-like ORFs of eight herpesviruses (Jacobson at al ., J. Virol., 49, 947-959, 1989). We have therefore designated this BH V1 ORF as the homolog of the HSV1 UL24 ORF with which it also shares a common position and orientation relative to the rk ORF. The BHV1 UL24 -like ORF is contained within a 5.2-kb RNA transcript initiating withi n the tk ORF and is the largest in a group of four 3'-coterminal trans cripts. This transcript pattern closely resembles that observed in HSV 1-infected cells where five transcripts, the two largest of which cont ain the UL24 ORF, appear to be 3'-coterminal. In contrast to HSV1 muta nts with lesions in the UL24 ORF, a BHV1 deletion mutant which failed to produce detectable levels of the 5.2-kb transcript grew nearly as w ell as wild-type virus. (C) 1994 Academic Press, Inc.