Cytokine-inducible expression in endothelial cells of an I kappa B alpha-like gene is regulated by NF kappa B.
The transient expression of many different genes is mediated by the inducible transcription factor p50-p65 NF kappa B, which in turn is regulated by complex formation with its inhibitor I kappa B alpha. We describe here that in porcine aortic endothelial cells, either IL-1 alpha, TNF alpha or LPS upregulates an inhibitor of NF kappa B which we refer to as ECI-6. ECI-6 is by structural and functional criteria an I kappa B alpha protein, the porcine homologue of MAD-3, pp40 and RL/IF-1. We have studied the promoter of the ECI-6/I kappa B alpha gene and provide three lines of evidence that its expression is directly regulated by NF kappa B. First, the 5' regulatory region of ECI-6/I kappa B alpha contains two sites that bind NF kappa B in electrophoretic mobility shift assays. Second, expression following transfection of an ECI-6/I kappa B alpha promoter-luciferase reporter construct is dependent on a co-transfected NF kappa B-p65 subunit. Third, pretreatment of endothelial cells with antioxidants, agents that inhibit activation of NF kappa B, inhibit the expression of ECI-6/I kappa B alpha. We conclude that the regulated expression of ECI-6/I kappa B alpha could represent a novel feedback mechanism by which NF kappa B downregulates its own activity after transient activation of target genes has been achieved.
de Martin
R
R
Vienna International Research Cooperation Center (VIRCC), Austria.
Vanhove
B
B
Cheng
Q
Q
Hofer
E
E
Csizmadia
V
V
Winkler
H
H
Bach
F H
FH
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002478:Cells, Cultured; D003001:Cloning, Molecular; D016207:Cytokines / Q000502:physiology*; D004247:DNA; D004268:DNA-Binding Proteins / Q000235:genetics*; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D005786:Gene Expression Regulation; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000502:physiology*; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013552:Swine; D051996:Transcription Factor RelA
D016207:Cytokines; D004268:DNA-Binding Proteins; C082225:ECI-6 protein, Sus scrofa; D016328:NF-kappa B; D012333:RNA, Messenger; D051996:Transcription Factor RelA; D004247:DNA