Properties of two 5'-coterminal RNAs transcribed part way and across the S component origin of DNA synthesis of the herpes simplex virus 1 genome.

In cells infected with herpes simplex virus 1 the domains of the two identical origins of viral DNA synthesis in the S component (Oris) are transcribed in two 5'-coterminal RNAs. OriSRNA1, synthesized early in infection and also in the absence of protein synthesis by infected cells, runs antisense to and terminates at the transcription initiation site for alpha genes 22 or 47. OriSRNA2, reported earlier, was detected in cells 14 hr after infection; it extends across the origin and is coterminal with the alpha 4 mRNA. Whereas the OriSRNA2 of herpes simplex virus 1 (HSV-1) contains an open reading frame, the corresponding herpes simplex virus 2 (HSV-2) transcript does not. However, in the two viruses, the transcription initiation sites are 260 (HSV-1) to 180 (HSV-2) nucleotides distant from the corresponding origins of DNA synthesis.