Comparison of immediate-early transcripts among bovine herpesvirus type 1 and type 5 strains differing in neurovirulent potential

Abstract

Northern (RNA) blot analysis was used to compare immediate-early (IE) transcripts among strains of bovine herpesvirus type 1 and type 5 differing in neurovirulent potential. Results obtained from the neurovirulent strain N569 were compared to those from two non-neurovirulent strains, Jura and K22. Strain N569 expressed three major IE transcripts with similar size and transcription pattern as previously reported for strain Jura and K22 (Wirth et al., 1989, 1991, 1992), except for some differences in the 5' terminal sequence common to the alternative spliced IE transcripts IER4.2 and IER2.9. More significant differences were discovered for some minor IE transcripts. Those transcribed over joined genome ends during replicative phase were found to be drastically overexpressed for strain N569 under IE condition. Among them two very long IE transcripts were detected clearly for strain N569, however hardly recognized for strain Jura and K22. These two transcripts were found to be encoded in addition to the joined terminal HindIII genome fragments by the second HindIII fragment J from the left genome end.