In vivo protein-DNA interactions at the kinin B1 receptor gene promoter: No modification on interleukin-1 beta or lipopolysaccharide induction
✍ Scribed by Martin Angers; Régen Drouin; Magdalena Bachvarova; Isabelle Paradis; François Marceau; Dimcho R. Bachvarov
- Publisher
- John Wiley and Sons
- Year
- 2000
- Tongue
- English
- Weight
- 481 KB
- Volume
- 78
- Category
- Article
- ISSN
- 0730-2312
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✦ Synopsis
The kinin B 1 receptor (B 1 R) gene is strongly upregulated following tissue injury and inflammation. In an attempt to define the regulatory elements that account for the control of B 1 R gene expression, we have conducted in vivo footprinting analysis of the B 1 R gene promoter region in three human cell types: embryonic lung fibroblast cells (IMR-90), embryonic kidney cells (HEK-293), and primary cultures of vascular umbilical smooth muscle cells. Initial in vitro delineation of the B 1 R gene promoter by transient transfection experiments with a reporter gene indicated that a 1.4-kb region, located just upstream of the transcription initiation site, bears all the characteristics of a core promoter with a functional TATA box and additional positive and negative control elements, as some of them could be tissue-specific. In vivo ultraviolet and dimethylsulfate footprinting analyses of the 1.4-kb region revealed no difference between the footprint patterns in the three cell types studied. We found that even in the noninduced state, the B 1 R gene promoter is possibly bound by several sequence-specific DNA binding proteins (GATA-1, PEA3, AP-1, CAAT, Sp1, Pit-1a, Oct-1, CREB). Some other footprints were detected on sequences that do not correspond to any known transcription factor binding site. No additional changes in protein-DNA complexes were observed upon treatment with interleukin-1 beta (IL-1) or bacterial lipopolysaccharide, shown previously to induce B 1 R gene expression. These results indicate that complex protein-DNA interactions exist at the B 1 R gene promoter prior to induction by external stimuli even in cells (HEK-293) that do not express a functional B 1 R.