Transcription factor binding and spacing constraints in the human beta-actin proximal promoter.
The human beta-actin promoter, including its 5' flanking region and 5' untranslated region, is ubiquitously active in mammalian cells in culture. In this report we investigated the transcriptional activity of, and the protein-DNA interactions that occur within, the proximal region of the human beta-actin promoter. Efficient beta-actin promoter activity in transfected human HeLa cells requires only 114bp of 5' flanking sequences. Two of the cis-actin regulatory elements within this region of the beta-actin promoter, the CCAAT box and proximal CCArGG box, are specific in vitro binding sites for the transcription factors, nuclear factor Y (NF-Y) and serum response factor (p67SRF), respectively. These two elements are required together to stimulate in vivo transcription from the homologous as well as a heterologous promoter. Finally, a particular spatial alignment between the CCAAT box and proximal CCArGG box is required for trans-activation in vivo. The above provides strong evidence for a functional interaction between NF-Y and p67SRF when bound to their respective binding sites in the beta-actin promoter.
Danilition
S L
SL
Division of Cellular and Molecular Biology, Ontario Cancer Institute/Princess Margaret Hospital, Toronto, Canada.
Frederickson
R M
RM
Taylor
C Y
CY
Miyamoto
N G
NG
D000199:Actins / Q000235:genetics*; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics; D012689:Sequence Homology, Nucleic Acid; D026362:Serum Response Factor; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic / Q000235:genetics*; D014162:Transfection / Q000235:genetics
D000199:Actins; D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D026362:Serum Response Factor; D014157:Transcription Factors