Immediate-early transcription of Herpesvirus saimiri

Transcription of Herpesvirus saimiri was characterized during the initial phases of productive infection by Northern blot analyses and hybridizations of radioactive cDNA with cloned fragments of virion L-DNA. Under conditions of immediate-early transcription, e.g., blocking of viral protein synthesis by cycloheximide, a single cytoplasmic polyadenylated viral RNA of 2.7 kilobases was found in infected cells. The sequence coding for this RNA was between map units 0.89 and 0.93; it was transcribed from right to left in prototype arrangement of M-DNA. The immediate-early mRNA of lytically infected cells appeared to be very similar, if not identical, to the single viral RNA species found in lymphoid cells transformed by H. saimiri.