First Author | Kuprash DV | Year | 1995 |
Journal | Oncogene | Volume | 11 |
Issue | 1 | Pages | 97-106 |
PubMed ID | 7624137 | Mgi Jnum | J:31153 |
Mgi Id | MGI:78637 | Citation | Kuprash DV, et al. (1995) Conserved kappa B element located downstream of the tumor necrosis factor alpha gene: distinct NF-kappa B binding pattern and enhancer activity in LPS activated murine macrophages. Oncogene 11(1):97-106 |
abstractText | Transcriptional activation of various genes by lipopolysaccharide (LPS) is known to be mediated, at least in part, by the NF-kappa B/Rel family of transcription factors. We have identified a novel kappa B element located immediately downstream of the TNF-alpha gene that is conserved together with its flanking sequences across species lines and can act as an LPS-responsive enhancer for reporter gene constructs driven by the minimal TNF promoter. In extracts from activated murine macrophages and macrophage cell lines this element binds several non-canonical NF-kappa B/Rel complexes, in addition to p50 (NFKB1) homodimer and p50-p65 (NKFB1-RelA) heterodimer. Combination of high-resolution electrophoretic mobility shift assays (EMSA) with monospecific antibodies and u.v.-cross-linking indicates that the prominent slow migrating complex III contain p65 homodimer and c-Rel. The appearance of complex III in EMSA parallels the translocation of p65 and c-Rel into the nucleus and occurs shortly after LPS induction. Transfection experiments with reporter constructs driven by this kappa B element indicate strong inducibility by LPS and p65, moderate inducibility by c-Rel and repression by p50. Functional activity of sandwich TNF-CAT-TNF constructs further suggests that LPS-inducible transcriptional activation of the TNF gene in murine macrophages may be partly mediated by a downstream enhancer. |