Activation of the interleukin-5 promoter by cAMP in murine EL-4 cells requires the GATA-3 and CLE0 elements.
Interleukin-5 (IL-5) plays a central role in the growth and differentiation of eosinophils and contributes to several disease states including asthma. Accumulating evidence suggests a role for cAMP as an immunomodulator; agents that increase intracellular cAMP levels have been shown to inhibit production of cytokines predominantly produced by T helper (Th) 1 cells such as IL-2 and interferon gamma (IFN-gamma). In contrast, the production of IL-5, predominantly produced by Th2 cells, is actually enhanced by these agents. In this report, we have performed transient transfection experiments with IL-5 promoter-reporter gene constructs, DNase I footprinting assays, and electrophoretic mobility shift assays to investigate the key regulatory regions necessary for activation of the IL-5 promoter by dibutyryl cAMP and phorbol esters in the mouse thymoma line EL-4. Taken together, our data demonstrate the critical importance of two sequences within the IL-5 5'-flanking region for activation by these agents in EL-4 cells: one, a highly conserved 15-base pair element present in genes expressed by Th2 cells, called the conserved lymphokine element 0 (CLE0; located between -53 and -39 in the IL-5 promoter), and the other, two overlapping binding sites for the transcription factor GATA-3 (but not GATA-4) between -70 and -59. Taken together, our data suggest that activation via the unique sequence combination GATA/CLE0 results in selective expression of the IL-5 gene in response to elevated levels of intracellular cAMP.
Siegel
M D
MD
Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
Zhang
D H
DH
Ray
P
P
Ray
A
A
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D001667:Binding, Competitive; D002460:Cell Line; D017931:DNA Primers; D004268:DNA-Binding Proteins / Q000378:metabolism*; D050990:GATA3 Transcription Factor; D050991:GATA4 Transcription Factor; D015972:Gene Expression Regulation, Neoplastic; D015848:Interleukin-5 / Q000096:biosynthesis* / Q000235:genetics*; D008156:Luciferases / Q000096:biosynthesis; D008222:Lymphokines / Q000378:metabolism*; D008223:Lymphoma; D051379:Mice; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000302:isolation & purification / Q000378:metabolism; D015345:Oligonucleotide Probes / Q000737:chemistry / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D011994:Recombinant Proteins / Q000096:biosynthesis; D015534:Trans-Activators / Q000378:metabolism*; D014157:Transcription Factors / Q000302:isolation & purification / Q000378:metabolism*; D014162:Transfection; D014407:Tumor Cells, Cultured; D001616:beta-Galactosidase / Q000096:biosynthesis
D017931:DNA Primers; D004268:DNA-Binding Proteins; D050990:GATA3 Transcription Factor; D050991:GATA4 Transcription Factor; C494748:Gata3 protein, mouse; D015848:Interleukin-5; D008222:Lymphokines; D009687:Nuclear Proteins; D015345:Oligonucleotide Probes; D011994:Recombinant Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D008156:Luciferases; D001616:beta-Galactosidase