Identification and functional characterization of a polymorphic oestrogen response element in the human coagulation factor IX gene promoter.
The liver expressed procoagulant factor IX (FIX) shows inter-individual variation in levels, some of which is heritable. Raised levels of FIX are associated with a thrombotic tendency. This study demonstrated that, in females but not males, part of this variation in FIX levels is due to polymorphic genotype at a locus in the factor IX gene (F9) promoter 698 bp upstream of the major transcription initiation site (-698C/T). The -698C allele (associated with higher FIX level) shows closer homology to a canonical ORE sequence and a higher binding affinity for oestrogen receptor alpha than the -698T allele. Reporter gene vectors were constructed with elements spanning residues -738 to +50 of the F9 promoter corresponding to wild type -698C and -698T alleles. A related series of vectors comprising three copies of the F9 ORE driving expression of a minimal synthetic promoter were also created. Transfection into the liver-derived HepG2 and erythroleukaemic K562 cell lines demonstrated increased levels of expression in the presence of oestrogenic factors when compared to those found in their absence; this stimulation was more pronounced in the non-liver derived K562 cell line and from the reporter vectors containing promoter elements corresponding to the -698C allele.
Adams
B
B
Academic Unit of Haematology, Division of Medicine and Biomedical Sciences, University of Sheffield, Sheffield, UK.
Western
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AK
Winship
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PR
D001483:Base Sequence; D002478:Cells, Cultured; D024202:Electrophoretic Mobility Shift Assay / Q000379:methods; D004967:Estrogens / Q000235:genetics*; D005164:Factor IX / Q000032:analysis / Q000235:genetics* / Q000378:metabolism; D005260:Female; D005822:Genetic Vectors; D006801:Humans; D020014:K562 Cells; D008297:Male; D008969:Molecular Sequence Data; D011110:Polymorphism, Genetic; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011960:Receptors, Estrogen / Q000378:metabolism; D020218:Response Elements; D012737:Sex Factors; D014162:Transfection
D004967:Estrogens; D011960:Receptors, Estrogen; D005164:Factor IX