Analysis of the promoter sequences of the UL9 gene of herpes simplex virus type 1.

The origin-binding protein, encoded by the UL9 gene of herpes simplex virus-1 (HSV-1), has the properties of an initiator of DNA replication. Since onset of lytic replication of the virus can be critically controlled by availability of the initiator protein, we have analyzed the sequences upstream of the UL9 gene in a monkey kidney cell line (Vero). In this communication, we report the presence of three UL9 transcripts and multiple transcription initiation sites of the UL9 gene in HSV-1-infected cells. The presence of multiple transcription initiation sites for the UL9 gene is consistent with the absence of a TATA element 5'- to the UL9 ORF. A 395-bp upstream sequence encompassing all UL9 transcription initiation sites was active in expressing a reporter gene and was induced by viral immediate-early proteins. This result is consistent with the earlier observation that immediate-early proteins of HSV-1 induce viral early genes.