THE HERPES-SIMPLEX VIRUS TYPE-I UL37 GENE-PRODUCT IS A COMPONENT OF VIRUS-PARTICLES

The herpes simplex virus type 1 UL37 gene encodes a protein with an M( r) of 120K that is produced at late times after infection. To study th e properties of this protein we have linked a 10 amino acid epitope de rived from a human cytomegalovirus protein to the UL37 polypeptide cod ing sequences by inserting an oligonucleotide at a SpeI site that is u nique in the virus genome and lies close to the 3' end of the open rea ding frame. From studies on the resultant virus recombinant using a mo noclonal antibody that recognizes the inserted epitope we find that, c ontrary to a previous report, the UL37 protein is a structural compone nt of both virions and L particles and is present in the tegument of v irus particles. Indirect immunofluorescence analysis revealed that the protein is distributed throughout infected cells but is more abundant in the cytoplasm than the nucleus.