Serotonin-inducible transcription of interleukin-1alpha in uterine smooth muscle cells requires an AP-1 site: cloning and partial characterization of the rat IL-1alpha promoter.
Interleukin-1 has been shown to contribute to infection-induced inflammatory processes during pregnancy. Prior work from this laboratory has demonstrated that serotonin-induced IL-1alpha also is required for the in-vitro production of collagenase in uterine smooth muscle cells, a normal, non-inflammatory process that occurs in-vivo during post-partum uterine involution. To understand the molecular mechanisms that regulate transcription of the IL-1alpha gene in these cells, we isolated and characterized 1.6 kilobases of the 5'-flanking region of the rat IL-1alpha gene. Sequencing and primer extension identified a single transcription start site and multiple potential regulatory elements, including a TATA box at - 30 bp, a CAAT box at - 74 bp, and a conserved AP-1 site at - 9 bp. This 5'-flanking DNA exhibited low basal promoter activity that was inducible by serotonin. Serotonin-induced promoter activity was unaffected or induced by either medroxyprogesterone or IL-1 receptor antagonist. This occurred despite the ability of both of these hormones to markedly decrease IL-1alpha mRNA. Deletional analysis revealed a strong repressor in the region between - 147 and - 98 bp; removal of this sequence resulted in a fivefold higher basal promoter activity that was still serotonin responsive. Constitutive promoter activity appeared to reside between - 97 and - 22 bp. Deletion of this promoter region, which contained the TATA and CAAT boxes and an NF-IL-6/PEA-3 site, resulted in decreased basal transcriptional activity to the low level seen in larger constructs. Mutational analysis showed that serotonin-inducible transcriptional activity was mediated, at least in part, by the conserved AP-1 site at - 9 bp. This site is located within a larger extended palindromic region: 5'-AAGCCTGACTCAGACTT-3', that together effects both the basal and serotonin-inducible expression of the IL-1alpha gene.
Huang
T T
TT
Department of Biochemistry and Molecular Biology, Albany Medical College, NY 12208, USA.
Vinci
J M
JM
Lan
L
L
Jeffrey
J J
JJ
Wilcox
B D
BD
D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D003001:Cloning, Molecular; D004252:DNA Mutational Analysis; D005260:Female; D016166:Free Radical Scavengers / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects; D007375:Interleukin-1 / Q000096:biosynthesis / Q000235:genetics*; D008969:Molecular Sequence Data; D009130:Muscle, Smooth / Q000502:physiology*; D011247:Pregnancy; D011401:Promoter Regions, Genetic; D051381:Rats; D017207:Rats, Sprague-Dawley; D016415:Sequence Alignment; D012701:Serotonin / Q000494:pharmacology*; D018808:Transcription Factor AP-1 / Q000235:genetics*; D014158:Transcription, Genetic / Q000187:drug effects; D014599:Uterus / Q000502:physiology
D016166:Free Radical Scavengers; D007375:Interleukin-1; D018808:Transcription Factor AP-1; D012701:Serotonin