Fos and Jun repress transcription activation by NF-IL6 through association at the basic zipper region.

TitleFos and Jun repress transcription activation by NF-IL6 through association at the basic zipper region.
Publication TypeJournal Article
Year of Publication1994
AuthorsHsu W, Kerppola TK, Chen PL, Curran T, Chen-Kiang S
JournalMol Cell Biol
Date Published1994 Jan
KeywordsBase Sequence, Binding Sites, CCAAT-Enhancer-Binding Proteins, DNA Probes, DNA-Binding Proteins, Humans, Interleukin-6, Leucine Zippers, Molecular Sequence Data, Nuclear Proteins, Proto-Oncogene Proteins c-fos, Proto-Oncogene Proteins c-jun, RNA, Messenger, Signal Transduction, Transcriptional Activation

NF-IL6 and AP-1 family transcription factors are coordinately induced by interleukin-6 (IL-6) in a cell-type-specific manner, suggesting that they mediate IL-6 signals in the nucleus. We show that the basic leucine zipper (bZIP) region of NF-IL6 mediates a direct association with the bZIP regions of Fos and Jun in vitro. This interaction does not depend on the presence of their cognate recognition DNA elements or the posttranslational modification of either partner. NF-IL6 homodimers can bind to both NF-IL6 and AP-1 sites, whereas Fos and Jun cannot bind to most NF-IL6 sites. Cross-family association with Fos or with Jun alters the DNA binding specificity of NF-IL6 and reduced its binding to NF-IL6 sites. NF-IL6 isoforms that differ in the site of translation initiation have distinct transcriptional activities. Activation of a reporter gene linked to the NF-IL6 site by NF-IL6 is repressed by Fos and by Jun in transient transfection assays. Thus, association with AP-1 results in repression of transcription activation by NF-IL6. The repression is NF-IL6 site dependent and may have a role in determining the promoter and cell type specificity in IL-6 signaling.

Alternate JournalMol Cell Biol
PubMed ID8264594
PubMed Central IDPMC358376
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