title: Two forms of NF-kappa B1 (p105/p50) in murine macrophages: differential regulation by lipopolysaccharide, interleukin-2, and interferon-gamma.
abstract: In macrophages, nuclear factor kappa B (NF-kappa B) has been shown to transactivate the promoters of many cytokines, including tumor necrosis factor-alpha (TNF-alpha). We have used the -510 kappa B binding site from the murine TNF-alpha promoter to assay the induction of NF-kappa B in murine macrophages by various stimuli. A basal level of NF-kappa B activity in murine macrophages was detectable, and this activity was enhanced by treatment of these cells with lipopolysaccharide (LPS) or interleukin-2 (IL-2). Interferon-gamma (IFN-gamma), an important regulator of macrophage gene expression, significantly enhanced NF-kappa B activity and altered the apparent molecular weight of the NF-kappa B1-like proteins in LPS-stimulated and IL-2-stimulated murine macrophages. The NRD (NF-kappa B/Rel/Dorsal) complexes induced by LPS and IFN-gamma were further characterized by addition of antisera to electrophoretic mobility shift assay (EMSA) reaction mixtures. NF-kappa B1/p50 was a component of all complexes, whereas RelA/p65 was present in the IFN-gamma/LPS-stimulated activity. IFN-gamma priming or treatment with LPS for 19 h resulted in an upregulation of the larger species of NF-kappa B1/p50. In addition, regulation of the two pools of NF-kappa B1/p50 by IFN-gamma was confirmed by Western immunoblot analysis of cytosolic and nuclear extracts. This is the first demonstration of the presence of two pools of NF-kappa B1/p50 differentially regulated in response to cytokine activation of macrophages.
authors.affiliation: Program in Cell and Molecular Biology, SUNY Health Science Center at Syracuse, USA.
authors.forename: M C
authors.initials: MC
authors.lastname: Brown
authors.forename: G D
authors.initials: GD
authors.lastname: Tomaras
authors.forename: M P
authors.initials: MP
authors.lastname: Vincenti
authors.forename: S M
authors.initials: SM
authors.lastname: Taffet
mesh_terms: D000818:Animals; D015153:Blotting, Western; D004268:DNA-Binding Proteins / Q000032:analysis; D007371:Interferon-gamma / Q000494:pharmacology*; D007376:Interleukin-2 / Q000494:pharmacology*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D016328:NF-kappa B / Q000096:biosynthesis*; D011233:Precipitin Tests; D011817:Rabbits
chemical_list: D004268:DNA-Binding Proteins; D007376:Interleukin-2; D008070:Lipopolysaccharides; D016328:NF-kappa B; D007371:Interferon-gamma