Binding of octamer factors to a novel 3'-positive regulatory element in the mouse interleukin-5 gene.
The development of eosinophilia is regulated by interleukin (IL)-5. The biological specificity of eosinophilia suggests a tight and independent regulation of IL-5 expression. A number of regulatory regions in the 5'-end of the IL-5 gene have been described; many of them are involved in the regulation of other genes, and it is not clear how the specific expression of IL-5 is regulated. In this study, we report the finding of a novel 3'-regulatory element. Data base analysis of a 2-kilobase fragment of the 3'-end of the mouse IL-5 gene revealed the presence of a 40-base pair-long repetitive sequence that consists of four direct repeats of ATGAATGA distributed in a symmetrical manner. This sequence, named mouse downstream regulatory element-1 (mDRE1), was shown to be protected in DNase I footprinting assays in vitro. Electrophoretic mobility shift assays using specific antibodies identified the transcription factors Oct-1 and Oct-2 as responsible for the formation of the specific complexes with mDRE1 and nuclear extracts from both EL4 and primary T-cells. Competition electrophoretic mobility shift assays with oligonucleotides containing different numbers of ATGAATGA repeats showed that Oct-1 and Oct-2 bind to different motifs in the mDRE1 sequence. Deletion of mDRE1 from a 9.5-kilobase IL-5 gene construct significantly decreased the expression of the luciferase reporter gene, suggesting that it plays a positive role in the expression of the IL-5 gene.
Salerno
M S
MS
Molecular Immunology Group, School of Biomedical Sciences, Curtin University of Technology, Perth 6000, Australia.
Mordvinov
V A
VA
Sanderson
C J
CJ
D000818:Animals; D001667:Binding, Competitive / Q000235:genetics; D002460:Cell Line; D018983:DNA Footprinting; D004268:DNA-Binding Proteins / Q000378:metabolism; D003854:Deoxyribonucleotides; D004802:Eosinophilia / Q000235:genetics; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D051863:Host Cell Factor C1; D015848:Interleukin-5 / Q000235:genetics*; D051379:Mice; D009154:Mutation; D009687:Nuclear Proteins / Q000378:metabolism; D050811:Octamer Transcription Factor-1; D050813:Octamer Transcription Factor-2; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics*; D012091:Repetitive Sequences, Nucleic Acid; D013601:T-Lymphocytes; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D014162:Transfection
D004268:DNA-Binding Proteins; D003854:Deoxyribonucleotides; C497693:Hcfc1 protein, mouse; D051863:Host Cell Factor C1; D015848:Interleukin-5; D009687:Nuclear Proteins; D050811:Octamer Transcription Factor-1; D050813:Octamer Transcription Factor-2; C494166:Pou2f1 protein, mouse; C489206:Pou2f2 protein, mouse; D014157:Transcription Factors