Stimulation of the human intercellular adhesion molecule-1 promoter by interleukin-6 and interferon-gamma involves binding of distinct factors to a palindromic response element.
Intercellular adhesion molecule-1 (ICAM-1) is a transmembrane glycoprotein that promotes adhesion in immunological and inflammatory reactions. ICAM-1 is expressed on cells of many lineages and is induced by interleukin-6 (IL-6) and interferon-gamma (IFN-gamma). Functional analysis of ICAM-1 promoter-luciferase constructs in HepG2 cells enabled us to identify a region between -110 and -37 mediating IL-6 and IFN-gamma responsiveness and containing a palindromic IL-6/IFN-gamma response element (pIRE). Site-directed mutagenesis of key nucleotides in the ICAM-1 pIRE abolished the effect of both IL-6 and IFN-gamma stimulation, while this pIRE element was sufficient to confer IL-6 and IFN-gamma responsiveness to a heterologous promoter. We further show by gel retardation analysis that distinct nuclear factors induced by both IL-6 or IFN-gamma specifically bind to this pIRE. Furthermore, treatment with IL-6 results in the formation of multiple complexes while IFN-gamma induces a single binding complex, both in HepG2 and monocytic U937 cells. Differentiation of U937 cells by exposure to 12-O-tetradecanoyl phorbol-13-acetate abolishes response to IL-6 but not IFN-gamma. Supershift data utilizing the ICAM-1 pIRE revealed that IFN-gamma and IL-6 both induce a factor antigenically related to IFN-gamma activation factor. We further provide data suggesting that IL-6 additionally activates an ICAM-1 pIRE binding factor related to the previously described acute-phase response factor in disparate cell types. We therefore conclude that the activation of these related nuclear factors by IL-6 and IFN-gamma is important in the regulation of ICAM-1 gene expression.
Caldenhoven
E
E
Hubrecht Laboratorium, Utrecht, The Netherlands.
Coffer
P
P
Yuan
J
J
Van de Stolpe
A
A
Horn
F
F
Kruijer
W
W
Van der Saag
P T
PT
D001483:Base Sequence; D001665:Binding Sites; D015815:Cell Adhesion Molecules / Q000235:genetics*; D002454:Cell Differentiation; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D006801:Humans; D018799:Intercellular Adhesion Molecule-1; D007371:Interferon-gamma / Q000494:pharmacology*; D015850:Interleukin-6 / Q000494:pharmacology*; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000096:biosynthesis; D011401:Promoter Regions, Genetic; D014407:Tumor Cells, Cultured
D015815:Cell Adhesion Molecules; D004268:DNA-Binding Proteins; D015850:Interleukin-6; D009687:Nuclear Proteins; D018799:Intercellular Adhesion Molecule-1; D007371:Interferon-gamma; D004247:DNA