Recombination signal sequence binding protein Jkappa is constitutively bound to the NF-kappaB site of the interleukin-6 promoter and acts as a negative regulatory factor.
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| Abstract |
Analysis by electrophoretic mobility shift assays (EMSA) of the different proteins associated with the kappaB sequence of the interleukin-6 (IL-6) promoter (IL6-kappaB) allowed us to detect a specific complex formed with the recombination signal sequence binding protein Jkappa (RBP-Jkappa). Single-base exchanges within the oligonucleotide sequence defined the critical base pairs involved in the interaction between RBP-Jkappa and the IL6-kappaB motif. Binding analysis suggests that the amount of RBP-Jkappa protein present in the nucleus is severalfold higher than the total amount of inducible NF-kappaB complexes but that the latter bind DNA with a 10-fold-higher affinity. A reporter gene study was performed to determine the functional implication of this binding; we found that the constitutive occupancy of the IL6-kappaB site by the RBP-Jkappa protein was responsible for the low basal levels of IL-6 promoter activity in L929sA fibrosarcoma cells and that RBP-Jkappa partially blocked access of NF-kappaB complexes to the IL-6 promoter. We propose that such a mechanism could be involved in the constitutive repression of the IL-6 gene under normal physiological conditions.
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| Authors | S Plaisance, W Vanden Berghe, E Boone, W Fiers, G Haegeman |
| Journal | Molecular and cellular biology (Mol Cell Biol) Vol. 17 Issue 7 Pg. 3733-43 (Jul 1997) ISSN: 0270-7306 [Print] United States |
| PMID | 9199307 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't) |
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