Structure and expression of the woodchuck herpesvirus genome.

This report describes the genome structure and location from which immediate-early transcription originates in the recently characterized woodchuck herpesvirus (herpesvirus marmota: HVM). Cross-hybridization of restriction fragments indicates that the HVM genome contains a tandem array of 1.5-kb repeat units. Additionally, terminal labeling and exonuclease experiments demonstrate that the repeated sequences lie at the termini of the genome. Hybridization of probes representing immediate-early transcription indicates that only a single predominant species of immediate-early RNA originates from a region near one end of unique sequences in the HVM genome. These results show remarkable similarity with group 2 of the gammaherpesvirinae. However, no homology was detected by conventional Southern blot hybridization between HVM and the gamma-2 prototype, herpesvirus saimiri. Therefore, we propose HVM to be a new member of the gammaherpesvirinae subfamily of herpesviruses.