Cyp19 encodes aromatase cytochrome P450, the key enzyme of oestrogen biosynthesis. In the bovine placenta, the majority of Cyp19 transcripts include a 5′-untranslated region which is encoded by exon 1.1; this suggests that its 5′-flanking region is the predominant placental promoter. The aim of the present investigation was to examine the promoter activity of this region and to map cis-acting regulatory elements in order to improve our understanding of the complex regulation of this gene within the placenta. As an initial approach, human JEG-3 choriocarcinoma cells were transiently transfected with reporter-gene constructs consisting of different 5′-flanking sequences of exon 1.1 fused to the luciferase gene as a reporter. To localise and further characterise functional cis-acting elements, targeted point mutations and electrophoretic mobility-shift experiments were used. The data demonstrate, for the first time, (1) that the bovine exon 1.1 5′-flanking sequence is an active promoter, (2) that 404 bp of this region are sufficient for constitutive reporter-gene expression in JEG-3 cells and (3) that the region includes at least two different enhancer elements; the data also suggest (4) that one of these elements consists of the E-box motif CATGTG and that the second enhancer element includes the half-site hexameric sequence AGGTCA and additional nucleotides flanking this element upstream.
CITATION STYLE
Kalbe, C., Fürbass, R., Schwerin, M., & Vanselow, J. (2000). Cis-acting elements regulating the placenta-specific promoter of the bovine Cyp19 gene. Journal of Molecular Endocrinology, 25(3), 265–273. https://doi.org/10.1677/jme.0.0250265
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