Nucleotide sequence and predicted amino acid sequence of a protein encoded in a small herpes simplex virus DNA fragment capable of trans-inducing alpha genes.

The five alpha genes of herpes simplex virus 1 are the first set of genes to be expressed after infection. Previous studies have shown that alpha genes resident in eukaryotic cells are induced by infection with herpes simplex virus 1 or 2 but not by other herpesviruses and indicate that the alpha trans-inducing factor was a structural component of the virion. This factor induces genes linked to a bona fide promoter and containing at the 5' end a small sequence derived from the promoter-regulatory domains of alpha genes. We report the sequence of a small DNA fragment shown previously to be capable of expressing the alpha trans-inducing factor in transient expression systems. The only gene encoded in its entirety in this fragment is predicted to specify a 479 amino acid protein with a Mr of 53,053. The precise termini of the 1.74-kilobase mRNA specifying this protein were determined in our 5' and 3' S1 nuclease protection studies.