Transforming Growth Factor-β and Ciliary Neurotrophic Factor Synergistically Induce Vasoactive Intestinal Peptide Gene Expression through the Cooperation of Smad, STAT, and AP-1 Sites

• Published in: The Journal of biological chemistry Vol. 276; no. 23; pp. 19966 - 19973
• Main Authors: Pitts, Richard L., Wang, Shuibang, Jones, Elizabeth A., Symes, Aviva J.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 08-06-2001
• Subjects: Animals; Base Sequence; Cell Line; ciliary neurotrophic factor; Ciliary Neurotrophic Factor - physiology; DNA Primers; Gene Expression Regulation - physiology; Smad protein; Stat protein; Transcription Factors - physiology; Transcription, Genetic - physiology; Transforming Growth Factor beta - physiology; Vasoactive Intestinal Peptide - genetics
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M011759200

The cytokine ciliary neurotrophic factor (CNTF) and transforming growth factor-β (TGF-β) both induce transcription of the vasoactive intestinal peptide (VIP) gene through a 180-base pair cytokine response element (CyRE) in the VIP promoter. While CNTF induces STAT and AP-1 proteins to bind to cognate sites in the VIP CyRE, the mechanism through which TGF-β acts to induce VIP gene transcription is not known. Here we show that Smad3 and Smad4 proteins can bind to two distinct sites within the VIP CyRE. These sites are absolutely required for the induction of VIP CyRE transcription by TGF-β. TGF-β induces endogenous Smad-containing complexes to bind to these sites in human neuroblastoma cells. CNTF and TGF-β synergize to induce VIP mRNA expression and transcription through the VIP CyRE. This synergy is dependent on the Smad, STAT, and AP-1 sites, suggesting that these two independent cytokine pathways synergize through the cooperation of pathway-specific transcription factors binding to distinct sites within the VIP CyRE.