Molecular structure and transcriptional regulation by nuclear factor-kappaB of the mouse kinin B1 receptor gene.
Kinins are important mediators in cardiovascular homeostasis, inflammation, and nociception. Two kinin receptors have been described, B 1 and B 2 . The B 1 receptor is normally absent in healthy tissues, but is highly induced under pathological conditions. To understand the molecular mechanism of B 1 receptor up-regulation, we determined the mouse B 1 receptor gene structure, isolated and characterized the promoter region and studied its transcriptional regulation. The mouse B 1 receptor gene contains two exons (with the entire coding region located in the second exon) and a TATA-less promoter with multiple transcription start sites. A 7.7-kbp portion of the 5'-flanking region was examined for promoter activity in vascular smooth muscle cells (VSMCs). A minimal 92-bp fragment, located immediately upstream of the transcription start region, exerted basal and lipopolysaccharide (LPS)-inducible transcription activity in the sense and antisense orientation, and was thereby identified as an enhancer element. Nuclear extracts from VSMCs showed basal and LPS-inducible binding activity of nuclear factor (NF)-kappaB at this sequence. B 1 receptor transcription activation in response to LPS was abolished by cotransfection with IkappaBalphaDeltaN, an NF-kappaB repressor. In summary, our results reveal the structure of the mouse B 1 receptor gene and the involvement of NF-kappaB in the inducible mouse kinin B 1 receptor expression under pathological conditions.
Merino
Vanessa F
VF
Department of Biophysics, Universidade Federal de São Paulo, CEP 04023-062 São Paulo, Brazil.
Silva
José A
JA
Araújo
Ronaldo C
RC
Avellar
Maria C W
MC
Bascands
Jean-L
JL
Schanstra
Joost P
JP
Paiva
Antonio C M
AC
Bader
Michael
M
Pesquero
João B
JB
D000818:Animals; D001483:Base Sequence; D004247:DNA / Q000032:analysis / Q000235:genetics; D004742:Enhancer Elements, Genetic / Q000235:genetics; D005786:Gene Expression Regulation; D008070:Lipopolysaccharides; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009131:Muscle, Smooth, Vascular / Q000378:metabolism; D032389:Myocytes, Smooth Muscle / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism*; D010957:Plasmids; D011401:Promoter Regions, Genetic / Q000235:genetics; D051381:Rats; D043783:Receptor, Bradykinin B1 / Q000235:genetics*; D014158:Transcription, Genetic; D014162:Transfection
D008070:Lipopolysaccharides; D016328:NF-kappa B; D043783:Receptor, Bradykinin B1; D004247:DNA