Genomic location and lack of phosphorylation of the HSV immediate-early polypeptide IE 12

Herpes simplex virus type 1 (HSV-1) induces an immediate-early (IE) polypeptide IE 12. An equivalent polypeptide coded by HSV-2 which migrated slightly more slowly on SDS-polyacrylamide gels was identified and designated IE 12.3. Analysis of the serotype of the IE polypeptide induced by five HSV-1/HSV-2 intertypic recombinants when correlated with their genome structures showed that IE 12/IE 12.3 mapped in the region spanning the TRs/Us junction. Unlike four other IE polypeptides induced by HSV-1 (IEs 175, 110, 68 and 63), IE 12 was not detectably phosphorylated.