Characterization of a bovine herpesvirus 4 immediate-early RNA encoding a homolog of the Epstein-Barr virus R transactivator.
Immediate-early (IE) RNA 2, the less abundant of two bovine herpesvirus 4 (BHV-4) RNAs detected in Madin-Darby bovine kidney cells infected in the presence of cycloheximide, is a 1.8-kb cytoplasmic polyadenylated RNA transcribed from the 8.3-kb HindIII fragment F. The structure of IE RNA 2 has been determined by S1 nuclease and exonuclease VII mapping, primer extension analysis, and sequencing of a partial cDNA. IE RNA 2 consists of a short, approximately 60-nucleotide 5' exon spliced to a 1.8-kb 3' exon. DNA sequence analysis revealed an open reading frame encoding 551 amino acids with sequence homology to the Epstein-Barr virus (EBV) R transactivator and its homolog in herpesvirus saimiri, HVS.R.IE 2 and HVS.R show higher homology to each other than to the EBV R transactivator. The homology is highest in the approximately 320 amino-terminal amino acids. All three proteins have acidic carboxyl termini but have little amino acid sequence homology in this region. In transient expression cotransfection assays, IE 2 activated expression from the BHV-4 early promoter-regulatory region of the major DNA-binding protein homolog over 100-fold in bovine turbinate cells. IE 1 was not necessary for this transactivation and did not augment it. However, IE 2 did not transactivate EBV or herpesvirus saimiri early promoter-regulatory regions that are transactivated by the EBV R transactivator or HVS.R.
Department of Pathobiology, Auburn University, Alabama 36849-5519.
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van Santen
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002417:Cattle; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000235:genetics; D005091:Exons / Q000235:genetics; D015967:Gene Expression Regulation, Viral; D006564:Herpesviridae / Q000235:genetics*; D004854:Herpesvirus 4, Human / Q000235:genetics; D017874:Immediate-Early Proteins; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics*; D012367:RNA, Viral / Q000235:genetics*; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D015534:Trans-Activators / Q000235:genetics*; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014764:Viral Proteins / Q000235:genetics*
D004268:DNA-Binding Proteins; C079185:IE2 protein, bovine herpesvirus type 4; D017874:Immediate-Early Proteins; D012333:RNA, Messenger; D012367:RNA, Viral; D015534:Trans-Activators; D014764:Viral Proteins; C072773:IE2 protein, polyhedrosis virus