IDENTIFICATION AND CHARACTERIZATION OF BICP27, AN EARLY PROTEIN OF BOVINE HERPESVIRUS-1 WHICH MAY STIMULATE MESSENGER-RNA-3' PROCESSING

Sequence analysis of the left genomic terminus of bovine herpesvirus 1 (BHV-1) revealed two convergently transcribed genes with 3' ends abou t 300 bp apart. The gene on the left is the previously described circ gene; that on the right was found to encode a protein of 400 amino aci ds which was designated BICP27 because of its homology to ICP27 (Vmw63 ) of herpes simplex virus 1 (HSV-1) and related proteins from other al pha-, beta- and gammaherpesviruses. Rabbit antisera raised against a s ynthetic oligopeptide representing the amino terminus of the predicted polypeptide demonstrated the presence of BICP27 in the nuclei of infe cted cells by in situ immunoadsorbent assays. In Western immunoblots, BICP27 was detected as a 50kDa BHV-1 specific protein expressed with e arly kinetics, in contrast to HSV-1 ICP27 which is an immediate early (IE) protein. A DNA fragment containing BICP27 coding sequences was in serted into a baculovirus genome. The recombinant BICP27 protein, iden tified by its reactivity with the antipeptide sera, exhibited the same electrophoretic mobility as BICP27 specified by BHV-1. Transient expr ession assays using target genes differing only in their poly(A) sites showed that BICP27, like its HSV-1 counterpart, may be involved in 3' processing of mRNA.