Organization of the Herpes Simplex Virus Type 1 Transcription Unit Encoding Two Early Proteins with Molecular Weights of 140000 and 40000

Abstract

The 5'' ends of 2 early herpes simplex virus type 1 mRNA were identified by nuclease S1 and exonuclease VII analysis using cloned virus DNA probes. These mRNA (5.0 and 1.2 [kilobase] kb), located within the genome region between map coordinates 0.56 and 0.60, are unspliced and share a 3'' terminus. Genomic DNA at the 5'' ends was sequenced and the 5'' termini were located on the virus DNA sequence. The DNA sequence has revealed signals involved in the initiation of transcription of both mRNA, and the 5'' end of the 1.2 kb mRNA is encoded within the internal sequences of the 5.0 kb mRNA. The probable translational initiation codons for the polypeptides specified by these mRNA were identified, and the results indicate that the coding regions of the 2 mRNA do not overlap.