title: The herpesvirus saimiri open reading frame (ORF) 50 (Rta) protein contains an at hook required for binding to the ORF 50 response element in delayed-early promoters.
abstract: The herpesvirus saimiri open reading frame (ORF) 50 encodes two proteins, which activate transcription directly, following interactions with delayed-early (DE) promoters containing a specific motif. In this report, we demonstrate that ORF 50 contains a DNA binding domain that has homology to an AT hook DNA binding motif. Deletion analysis of this domain reduces ORF 50-mediated transactivation of the DE ORF 6 and ORF 57 promoters by 100 and 90%, respectively. Furthermore, gel retardation experiments demonstrated that the AT hook motif is required for binding the ORF 50 response element in the promoters of DE genes. Single site-directed mutagenesis of the AT hook revealed that mutation of the glycine residue at position 408 to an alanine reduces ORF 50 transactivation of the ORF 57 promoter by 40%. Moreover, the mutation of multiple basic residues in conjunction with the glycine residue within the core element of the AT hook abolishes ORF 50-mediated transactivation. In addition, p50GFPDeltaAT-hook is capable of functioning as a trans-dominant mutant, leading to a reduction in virus production of approximately 50% compared to that for wild-type ORF 50.
authors.affiliation: School of Biochemistry and Microbiology, University of Leeds, Leeds, LS2 9JT United Kingdom.
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Walters
authors.forename: Kersten T
authors.initials: KT
authors.lastname: Hall
authors.forename: Adrian
authors.initials: A
authors.lastname: Whitehouse
mesh_terms: D024761:AT-Hook Motifs / Q000235:genetics* / Q000502:physiology; D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017353:Gene Deletion; D015967:Gene Expression Regulation, Viral; D006360:Heat-Shock Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006567:Herpesvirus 2, Saimiriine / Q000737:chemistry / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011401:Promoter Regions, Genetic / Q000235:genetics / Q000502:physiology; D020218:Response Elements / Q000235:genetics / Q000502:physiology*; D015533:Transcriptional Activation
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D006360:Heat-Shock Proteins; C104238:yqeV protein, Bacillus subtilis