Cell-type-specific induction of the UL9 gene of HSV-1 by cell signaling pathway

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. In this communication, we report that the UL9 promoter contains a cAMP-response element (CRE). Transient expression analyses show that dibutyryl cyclic AMP, known to elevate intracellular cAMP level, can induce the UL9 promoter in a rat pheochromocytoma cell line (PC12) but not in a non-neuronal human cell line (HeLa). Interestingly, a transcription factor that increases expression of a neuropeptide gene by interacting with CRE can also activate the UL9 promoter independent of cell type. Thus, our data suggest that extracellular stimuli, capable of interacting with the signaling pathway in neuronal cells, can activate UL9 gene expression, and different proteins may regulate UL9 expression in different cell types.