Characterization of a functional NF-kappa B site in the human interleukin 1 beta promoter: evidence for a positive autoregulatory loop.
The -300 region of the interleukin 1 beta (IL-1 beta) promoter contains a functional NF-kappa B binding site composed of the decamer sequence 5'-GGGAAAATCC-3'. Probes representing the -300 region or the NF-kappa B site alone interacted with NF-kappa B proteins present in phorbol myristate acetate-, lipopolysaccharide-, or Sendai virus-induced myeloid cell extracts as well as recombinant NFKB1 (p50) and RelA (p65); furthermore, NF-kappa B protein-DNA complex formation was dissociated in vitro by the addition of recombinant I kappa B alpha. Mutation of the NF-kappa B site in the context of the IL-1 beta promoter reduced the responsiveness of the IL-1 beta promoter to various inducers, including phorbol ester, Sendai virus, poly(rI-rC), and IL-1 beta. A 4.4-kb IL-1 beta promoter fragment linked to a chloramphenicol acetyltransferase reporter gene was also preferentially inducible by coexpression of individual NF-kappa B subunits compared with a mutated IL-1 beta promoter fragment. When multiple copies of the IL-1 beta NF-kappa B site were linked to an enhancerless simian virus 40 promoter, this element was able to mediate phorbol ester- or lipopolysaccharide-inducible gene expression. In cotransfection experiments, RelA (p65) and c-Rel (p85) were identified as the main subunits responsible for the activation of the IL-1 beta NF-kappa B site; also, combinations of NFKB1 (p50) and RelA (p65) or c-Rel and RelA were strong transcriptional activators of reporter gene activity. The presence of a functional NF-kappa B binding site in the IL-1 beta promoter suggests that IL-1 positively autoregulates its own synthesis, since IL-1 is a strong inducer of NF-kappa B binding activity. Thus, the IL-1 beta gene may be considered as an important additional member of the family of cytokine genes regulated in part by the NF-kappa B/rel family of transcription factors.
Hiscott
J
J
Lady Davis Institute for Medical Research, McGill University, Montreal, Quebec, Canada.
Marois
J
J
Garoufalis
J
J
D'Addario
M
M
Roulston
A
A
Kwan
I
I
Pepin
N
N
Lacoste
J
J
Nguyen
H
H
Bensi
G
G
D001483:Base Sequence; D001665:Binding Sites; D002460:Cell Line; D004247:DNA; D005786:Gene Expression Regulation; D006801:Humans; D007375:Interleukin-1 / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051841:Transcription Factor RelB; D014157:Transcription Factors; D015533:Transcriptional Activation; D014407:Tumor Cells, Cultured
D007375:Interleukin-1; D016328:NF-kappa B; D011518:Proto-Oncogene Proteins; C497593:RELB protein, human; D014157:Transcription Factors; D051841:Transcription Factor RelB; D004247:DNA