A novel SP-1 site in the human interleukin-1 beta promoter confers preferential transcriptional activity in keratinocytes.
To investigate the mechanisms of transcriptional activation of interleukin-1beta (IL-1beta) in non-monocytic cells, we constructed a series of reporter plasmids with the bacterial chloramphenicol acetyltransferase gene linked to various parts of the human IL-1beta promoter and performed transient transfection experiments. We identified a promoter segment that activates transcription most efficiently in keratinocytes. Electrophoretic mobility shift assays (EMSA) with a 43-mer oligonucleotide derived from the functionally identified cis-acting element revealed specific complexes. By competition analysis with transcription factor consensus sequence oligonucleotides and by immunosupershift, transcription factor SP-1 or a closely related protein was shown to bind to this regulatory element. The closest match to the known SP-1 consensus sequence within the respective region is a TCCCCTCCCCT motif. Mutation of this motif almost completely, and specifically, abolished the binding of two low-mobility complexes and led to a 95% decrease of constitutive transcriptional activation of a reporter construct IL-1beta (-170/+108). Likewise, activation of this reporter construct by tumor necrosis factor-alpha depended on the SP-1 site. These observations suggest that a so-far-unrecognized SP-1 site in the human IL-1beta promoter may participate in the transcriptional regulation of this gene in keratinocytes.
Husmann
M
M
Institut für Medizinische Mikrobiologie und Hygiene der Johannes-Gutenberg Universität Mainz, Germany.
Jehnichen
P
P
Jahn
B
B
Schlosshan
D
D
Romahn
E
E
Marx
J
J
D002461:Cell Line, Transformed; D002467:Cell Nucleus / Q000378:metabolism; D017930:Genes, Reporter / Q000276:immunology; D006801:Humans; D007375:Interleukin-1 / Q000235:genetics* / Q000378:metabolism; D015603:Keratinocytes / Q000378:metabolism*; D009000:Monocytes / Q000378:metabolism; D009154:Mutation / Q000276:immunology; D011401:Promoter Regions, Genetic / Q000276:immunology*; D016329:Sp1 Transcription Factor / Q000235:genetics* / Q000276:immunology / Q000502:physiology*; D014158:Transcription, Genetic / Q000276:immunology*; D015533:Transcriptional Activation / Q000276:immunology; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000494:pharmacology
D007375:Interleukin-1; D016329:Sp1 Transcription Factor; D014409:Tumor Necrosis Factor-alpha