Transcriptional regulation of Sertoli cell immediate early genes by interleukin-6 and interferon-gamma is mediated through phosphorylation of STAT-3 and STAT-1 proteins.
The immediate early genes are regulated by a variety of extracellular signals, including pleiotropic cytokines. The effects of the testicular cytokines, interleukin-6 (IL-6) and interferon-gamma (IFN-gamma), on signal transducers and activators of transcription 3 and 1 (STAT-3 and STAT-1) and on c-fos gene expression in primary Sertoli cells are suggestive of their roles in differential function. Using the tyrosine phosphorylation inhibitor, genistein, and electrophoretic mobility shift assay, we show that IL-6 and IFN-gamma induce nuclear factor STAT-3 and STAT-1 DNA-binding activity to the sis-inducible element of c-fos in a genistein-dependent pathway. Quantitative solution hybridization, Northern blot, and nuclear run-on analysis show that differential induction of c-fos, junB, and c-myc messenger RNA (mRNA) by these cytokines occur at transcriptional levels. IL-6 stimulates c-fos mRNA levels by 6-fold while increasing junB levels by 2-fold. IFN-gamma increases c-fos message 2-fold, but has no effect on junB mRNA levels. Furthermore, genistein treatment blocks the induction of c-fos and junB gene expression, demonstrating that tyrosine phosphorylation of STAT proteins is involved in the cytokine regulation of the Sertoli immediate early genes. H7, a serine/threonine phosphorylation inhibitor, also blocks c-fos gene induction by IL-6 and IFN-gamma, but does not affect the DNA-binding activities of STAT-3 and STAT-1. Finally, IL-6 treatment of Sertoli cells (3-6 h) increases the amounts of activating protein-1 binding to activating protein-1 element and c-myc transcription.
Jenab
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The Population Council, New York, New York 10021, USA.
Morris
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PL
D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005786:Gene Expression Regulation; D017781:Genes, Immediate-Early / Q000235:genetics*; D016762:Genes, fos; D016758:Genes, jun; D019833:Genistein; D007371:Interferon-gamma / Q000378:metabolism*; D015850:Interleukin-6 / Q000378:metabolism*; D007529:Isoflavones / Q000494:pharmacology; D008297:Male; D008958:Models, Molecular; D010766:Phosphorylation; D012313:RNA / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D050794:STAT1 Transcription Factor; D050796:STAT3 Transcription Factor; D012694:Serine / Q000378:metabolism; D012708:Sertoli Cells / Q000378:metabolism*; D013912:Threonine / Q000378:metabolism; D015534:Trans-Activators / Q000378:metabolism*; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014443:Tyrosine / Q000378:metabolism
D000970:Antineoplastic Agents; D004268:DNA-Binding Proteins; D015850:Interleukin-6; D007529:Isoflavones; D050794:STAT1 Transcription Factor; D050796:STAT3 Transcription Factor; C494081:Stat1 protein, rat; C494088:Stat3 protein, rat; D015534:Trans-Activators; D013912:Threonine; D014443:Tyrosine; D012694:Serine; D012313:RNA; D007371:Interferon-gamma; D004247:DNA; D019833:Genistein