Characterization of the protein product encoded by a splicing variant of the Marek's disease virus Eco-Q gene (Meq).
In the present study, we report the characterization of a 212-amino-acid polypeptide encoded by a splicing variant of the Marek's disease virus Eco-Q gene (Meq). This protein, referred to as Meq-sp, contains the N-terminal 100 amino acids of Meq, which include part of Meq's DNA binding/dimerization domain, but lacks the transactivation domain of Meq. Thus, Meq-sp was examined for its ability to bind to DNA and act as a transactivator. Results indicated that while Meq and Meq-sp could both bind to the AP-1 binding site, the 110 C-terminal amino acid residues of Meq-sp lacked the ability to function as a transactivator when fused to the GAL4 (1-147) DNA binding motif. To investigate whether Meq-sp can interact with Meq or with c-jun, protein-protein and protein-DNA interactions in vitro were examined. Results showed that Meq-sp can associate with both Meq and c-jun and bind to the AP-1 site with a higher affinity as a heterodimer with c-jun. These results suggest that Meq-sp could compete with Meq for heterodimer formation with c-jun and dimer binding to DNA and possibly act as a transdominant negative regulator of Meq activity in vivo.
Peng
Q
Q
Laboratory of Tumor Virology, Salem-Teikyo University/Tampa Bay Research Institute, St. Petersburg, Florida 33716, USA.
Shirazi
Y
Y
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D002642:Chick Embryo; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D008381:Herpesvirus 2, Gallid / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009856:Oncogene Proteins, Viral / Q000235:genetics / Q000378:metabolism*; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism; D018808:Transcription Factor AP-1 / Q000378:metabolism; D015533:Transcriptional Activation
D004268:DNA-Binding Proteins; C100369:Eco-Q protein, Gallid herpesvirus 2; D009856:Oncogene Proteins, Viral; D016755:Proto-Oncogene Proteins c-jun; D018808:Transcription Factor AP-1