STAT6 transcription factor binding sites with mismatches within the canonical 5'-TTC...GAA-3' motif involved in regulation of delta- and mu-opioid receptors.
Opioid receptors are expressed in neuronal and immune cells and regulated in response to immunological processes. Herein, we demonstrate up-regulation of the delta-opioid receptor gene by interleukin-4 in immune cells (primary T and polymorphonuclear leukocytes, Jurkat E6 T cells), and in NG 108-15 neuronal cells. We identified an interleukin-4-responsive element at nt -671 on the murine gene promoter, to which the transcription factor STAT6 binds, as shown by reporter gene analysis and STAT6/DNA interaction studies in living cells with transcription factor decoy oligonucleotides. STAT6 normally binds to palindromic DNA motifs with a 5'-TTC...GAA-3' core. Notably, the delta-opioid receptor STAT6 site (5'-TTC...GGA-3') is an imperfect palindrome with a mismatch within this core sequence. A systematic analysis of possible mismatch 5'-TTC...GAA-3' motifs revealed that STAT6 also binds to the sequence 5'-TTA...GAA-3'. This motif occurs as a polymorphism in the human mu-opioid receptor gene (Kraus et al. 2001 J. Biol. Chem 276, 43901-43908). We show that this mutated element has a significantly reduced STAT6 binding activity which correlates to its reduced interleukin (IL)-4 inducibility. In contrast, the non-canonical STAT6 site of the delta-opioid receptor binds STAT6 with similar high activity as a perfectly palindromic STAT6 site and is strongly inducible by IL-4.
Börner
Christine
C
Department of Pharmacology and Toxicology, University of Magdeburg, Magdeburg, Germany.
Wöltje
Michael
M
Höllt
Volker
V
Kraus
Jürgen
J
D020816:Amino Acid Motifs; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D045744:Cell Line, Tumor; D005786:Gene Expression Regulation / Q000187:drug effects; D015847:Interleukin-4 / Q000494:pharmacology; D007962:Leukocytes / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D009474:Neurons / Q000378:metabolism; D011110:Polymorphism, Genetic; D011401:Promoter Regions, Genetic / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D051381:Rats; D017465:Receptors, Opioid, delta / Q000235:genetics* / Q000378:metabolism*; D017450:Receptors, Opioid, mu / Q000235:genetics* / Q000378:metabolism*; D011994:Recombinant Proteins / Q000494:pharmacology; D050800:STAT6 Transcription Factor; D015534:Trans-Activators / Q000096:biosynthesis / Q000378:metabolism*; D015854:Up-Regulation
D017465:Receptors, Opioid, delta; D017450:Receptors, Opioid, mu; D011994:Recombinant Proteins; D050800:STAT6 Transcription Factor; C494100:Stat6 protein, mouse; D015534:Trans-Activators; D015847:Interleukin-4