Smubp-2 represses the Epstein-Barr virus lytic switch promoter.
Smubp-2 is a novel transcription factor that was first identified through its interaction with the immunoglobulin Smu region (Mizuta et al., 1993) and has been cloned by virtue of its binding to two 12-O-tetradecanoylphorbol-13-acetate-responsive elements in the Epstein-Barr virus immediate-early BZLF1 promoter (Gulley et al., 1997). In this report, we examined the effect of Smubp-2 overexpression on BZLF1 prom oter activity. Overexpression of Smubp-2 in the B lymphocyte cell line BJAB caused repression of the BZLF1 gene promoter. A 14-bp region that partially overlaps with a 12-O-tetradecanoylphorbol-13-acetate-responsive element was required for maximal repression by Smubp-2, but some repression was also seen with a minimal promoter containing only the BZLF1 promoter TATA box and an initiation site. A 30-bp fragment containing the 14-bp region could transfer Smubp-2-mediated repression to heterologous promoters. Smubp-2 was found to associate with the basal transcription factor TATA binding protein (TBP) and to disrupt the formation of a stable TBP-TFIIA-DNA complex on the BZLF1 promoter TATA box and the adenovirus E1B promoter TATA box. Repression of the BZLF1 promoter by overexpressed Smubp-2 was rescued by overexpression of the basal factor TFIIA. These results suggest that complete repression of the BZLF1 promoter by Smubp-2 involves disruption of a functional TBP-TFIIA-TATA box complex and requires the -93 bp-to--79 bp region of the promoter.
Zhang
Q
Q
Department of Pediatrics, The University of Texas Heath Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, Texas 78284, USA.
Wang
Y C
YC
Montalvo
E A
EA
D002460:Cell Line; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D011401:Promoter Regions, Genetic; D016385:TATA Box; D035181:TATA-Box Binding Protein; D013755:Tetradecanoylphorbol Acetate / Q000378:metabolism / Q000494:pharmacology; D015534:Trans-Activators / Q000235:genetics*; D035561:Transcription Factor TFIIA; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014764:Viral Proteins / Q000235:genetics*
C063676:BZLF1 protein, Herpesvirus 4, Human; D004268:DNA-Binding Proteins; C489892:IGHMBP2 protein, human; D035181:TATA-Box Binding Protein; D015534:Trans-Activators; D035561:Transcription Factor TFIIA; D014157:Transcription Factors; D014764:Viral Proteins; D013755:Tetradecanoylphorbol Acetate