DNase I footprinting of the human interleukin-5 gene promoter.
A characteristic feature of allergic asthma is the overexpression of the T helper type 2 (Th2) cytokines interleukin-4 (IL-4), IL-5 and IL-13 by T lymphocytes. Of these cytokines, IL-5 is critical for the growth, survival and recruitment of eosinophils which are thought to be responsible for the tissue damage observed in asthmatic airways. The expression of human IL-5 is primarily regulated at the transcriptional level; however, little is known about the mechanisms that control its transcription. Using nuclear extracts from allergen-specific human T-cell clones we have performed DNase I footprinting of the human IL-5 promoter in order to establish sites occupied by transcription factors. We show footprints covering the conserved lymphokine element 0 ¿(CLE0) -60 to -44 base pairs (bp) and GATA (-73 to -62 bp) elements, which have previously been identified to be important in the regulation of the murine IL-5 promoter. We also describe a footprint covering a considerably extended Octamer binding site (-249 to -217 bp), which encompasses two hitherto unidentified CCAAT/enhancer binding protein consensus binding sites. We have also identified a previously unknown Ets binding site (-274 to -264 bp). These novel data on the regions of the human IL-5 promoter that are bound by transcription factors should allow dissection of the regulatory mechanisms involved in the transcription of IL-5 in the T-helper lymphocytes of asthmatics.
Cousins
D J
DJ
Department of Respiratory Medicine and Allergy, King's College London, London, UK.
Richards
D
D
Kemeny
D M
DM
Romagnani
S
S
Lee
T H
TH
Staynov
D Z
DZ
D001249:Asthma / Q000276:immunology*; D001665:Binding Sites; D002999:Clone Cells; D018983:DNA Footprinting; D003850:Deoxyribonuclease I; D005786:Gene Expression Regulation; D006801:Humans; D015848:Interleukin-5 / Q000235:genetics*; D011401:Promoter Regions, Genetic; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013601:T-Lymphocytes / Q000276:immunology*; D014157:Transcription Factors
D015848:Interleukin-5; D014157:Transcription Factors; D003850:Deoxyribonuclease I