Transcription factors AP-3 and AP-2 interact with the SV40 enhancer in a mutually exclusive manner.
The 'core' sequence is critical for efficient transcriptional activity of the SV40 enhancer. Moreover, the core was shown to be involved in a signal transduction pathway elicited by treatment of cells with phorbol ester tumor promoters. We report here the identification and characterization of activator protein-3 (AP-3), which recognizes the core element. AP-3 was purified to near homogeneity and identified as a 48K polypeptide. The purified protein is an efficient transcriptional activator in vitro. In addition, we show that AP-3 and a second factor that recognizes the SV40 enhancer, AP-2, interact in a mutually exclusive manner. These studies should facilitate understanding of the mechanism by which the SV40 enhancer achieves its characteristic broad cell-type specificity.
Mercurio
F
F
Department of Biology, School of Medicine, University of California, San Diego, La Jolla 92093.
Karin
M
M
D001483:Base Sequence; D001665:Binding Sites; D004247:DNA / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D004742:Enhancer Elements, Genetic; D006367:HeLa Cells / Q000378:metabolism; D006801:Humans; D013539:Simian virus 40 / Q000235:genetics*; D050656:Transcription Factor AP-2; D014157:Transcription Factors / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*
D004268:DNA-Binding Proteins; D050656:Transcription Factor AP-2; D014157:Transcription Factors; C060759:enhancer-binding protein AP-3; D004247:DNA