Nuclear factor-IL6 activates the human IL-4 promoter in T cells.
Positive regulatory element I (PRE-I) is a strong enhancer element essential for expression of the human IL-4 gene. To identify transcription factors binding to PRE-I, we screened a cDNA expression library from Jurkat T cells and isolated a cDNA encoding nuclear factor (NF)-IL6 (also known as C/EBP beta). NF-IL6 mRNA was found in human Jurkat T cells and in the mouse Th2 clone D10, but not in Th1 clone 29. rNF-IL6 expressed in bacteria was shown to specifically bind to PRE-I. PRE-I forms multiple DNA-protein complexes with nuclear extracts from Jurkat cells. Some of these complexes were demonstrated to contain NF-IL6 by using anti-C/EBP beta Abs. Overexpression of NF-IL6 enhanced expression of the chloramphenicol acetyl transferase reporter gene linked to the PRE-I-thymidine kinase or the human IL-4 promoter more than 10-fold in Jurkat cells. Promoter deletion studies revealed two additional NF-IL6 binding sites located at positions -44 to -36 (C/EBP proximal) and -87 to -79 (C/EBP medial), respectively. Our results demonstrate that NF-IL6 is involved in transcriptional activation of the human IL-4 promoter in T cells.
Davydov
I V
IV
Tumor Immunology Program, German Cancer Research Center, Heidelberg, Germany.
Krammer
P H
PH
Li-Weber
M
M
D000818:Animals; D001483:Base Sequence; D022762:CCAAT-Enhancer-Binding Proteins; D002460:Cell Line; D004247:DNA; D004268:DNA-Binding Proteins / Q000378:metabolism / Q000502:physiology*; D005786:Gene Expression Regulation; D015723:Gene Library; D006801:Humans; D015847:Interleukin-4 / Q000235:genetics*; D051379:Mice; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000502:physiology*; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000032:analysis; D013601:T-Lymphocytes / Q000276:immunology*; D014157:Transcription Factors / Q000502:physiology*
D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins; C090091:In4 complex; D009687:Nuclear Proteins; D012333:RNA, Messenger; D014157:Transcription Factors; D015847:Interleukin-4; D004247:DNA