Sequence analysis of the alpha trans-inducing factor of bovine herpesvirus type 5 (BHV-5)

Bovine herpesvirus (BHV), a member of the subfamily Alphaherpesvirinae, is classified into neurovirulent and non-neurovirulent subtypes on a basis of differential neuropathogenicities. Transcription of viral immediate early (IE) genes during alphaherpesvirus gene expression, is mediated by a multi-component immediate early complex (IEC) integrated by the viral tegument protein alpha trans-inducing factor (alpha-tif), a host cell protein (HCF), and a host Octamer protein (Oct). In this paper, we present a sequence analysis of the alpha-tif of the encephalitic BHV subtype, bovine herpesvirus type 5 (BHV-5). Bovine herpesvirus type 1 (BHV-1) and BHV-5 alpha-tifs share 98% amino acid sequence homology. However, BHV-5 alpha-tif is 23 residues shorter at the amino terminus than BHV-1 alpha-tif. Amino acid alignment of the alpha-tifs of BHV-1 and BHV-5 with other alphaherpesviruses indicates areas of conserved motifs but also important differences located mainly at the amino and carboxyl termini.