Early and late transcriptional phases in the replication of lumpy-skin-disease virus.

Approximately 71 of the estimated 145 kilobase pairs of the genome of the South African isolate of lumpy-skin-disease virus, Neethling strain, was cloned into the plasmid vector pBluescribe. Selected clones were used in Northern blot analysis to investigate the replication cycle of the virus. The synthesis of early mRNA was initiated immediately after infection, and continued for approximately 9 h. The transition to late-gene transcription occurred approximately 10 h post-infection and required DNA replication. Transcription of endogenous late genes cannot occur when viral DNA replication is prevented, while it is activated after DNA replication has occurred. The cloned fragments of the genome are expected to help in the identification of important promoter elements.