Upstream NFIL-6-like site located within a DNase I hypersensitivity region mediates LPS-induced transcription of the murine interleukin-1 beta gene
Godambe, S.A.; Chaplin, D.D.; Takova, T.; Bellone, C.J.
Journal of Immunology 153(1): 143-152
1994
ISSN/ISBN: 0022-1767 PMID: 8207231 Document Number: 428305
To define the cis-acting elements that regulate LPS-stimulated IL-1 beta gene transcription, the murine Il-1 beta gene was analysed by digestion with DNase I. At least 2 hypersensitive sites were located between 2200 and 2600 bp upstream of the transcription start site in mononuclear phagocytes, but not in an IL-1 non-producing immature T cell line. Specific DNA sequences required for LPS induction of IL-1 beta gene expression were identified within the DNase I hypersensitive (DH) region using transfection of reporter constructs that contained portions of the IL-1 beta 5'-flanking region. Two specific DNA sequences were targets for nuclear factor binding as assessed with use of electrophoretic mobility shift analysis (EMSA). One site contained a consensus sequence for NFIL-6 binding. Base substitutions within this NFIL-6 site resulted in virtual elimination of LPS-induced IL-1 beta gene transcription. Introduction of multimers of the NFIL-6-like sequence immediately 5' to homologous or heterologous promoters conferred LPS-induced transcription, indicating that this NFIL-6-like consensus site was a transcriptional activator. Anti-C/EBP beta (NFIL-6) and anti-C/EBP delta (NFIL-6 beta ) Abs identified both of these proteins in complexes formed between the NFIL-6-like element and mononuclear cell nuclear extracts. C/EBP delta (NFIL-6 beta ) was not detected in complexes utilizing extracts from the IL-1 nonproducing T cell line. These data are consistent with the requirement for C/EBP beta (NFIL-6) and C/EBP delta (NFIL-6 beta ) in the activation of murine IL-1 beta gene expression by endotoxin.