The gene encoding the major capsid protein (MCP) VP5 of herpesvirus of turk
eys (HVT) was identified and sequenced. It has a single open reading frame
of 4236 nucleotides encoding 1412 aa protein. The gene is flanked by VP23 a
nd UL20 sequences and is localized in the unique long region (U-L) within t
he BamHI-B fragment. Comparison of amino acid homology has shown its clear
position among the alpha-herpesviruses rather than beta- or gamma-herpesvir
uses. The VP5 is expressed from polycistronic mRNA together with the UL20 a
nd the VP23 genes. The 7,2 kb RNA transcript is lacking any promoter elemen
ts or polyA signal in intergenomic regions between VP5 and UL20 or VP5 and
VP23 genes, respectively. Multiple alignment of known major capsid protein
sequences of all herpesvirus groups revealed presence of seven highly homol
ogus clusters suggesting that the corresponding protein domains might play
an important role in folding of MCP and assembly of herpesvirus capsid.