Two orphan receptors binding to a common site are involved in the regulation of the oxytocin gene in the bovine ovary.
The peptide hormone oxytocin is highly expressed in the hypothalamus within only a small number of magnocellular neurons. However, it is also expressed in a much larger number of cells in the bovine corpus luteum at high levels in an estrous cycle-dependent manner. By using nuclear extracts from this tissue for in vitro binding studies, two protein complexes have been shown to bind to a common site in the bovine oxytocin promoter. One of these proteins has been identified as the bovine homologue of the chicken ovalbumin upstream promoter transcription factor (COUP-TF). The second protein is here characterized as the bovine homologue of a tissue-specific transcription factor, steroidogenic factor 1 (SF-1). The relative expression of these two factors during luteal development correlates with the level of luteal oxytocin gene expression, with SF-1 being the factor binding to the promoter of the oxytocin gene when this promoter is activated. Cotransfection experiments using the murine testicular cell line TM4 show that SF-1 can stimulate the expression of a transfected oxytocin gene, suggesting that SF-1 may be involved in upregulation of the oxytocin gene in vivo, possibly by transducing a stimulatory signal to the RNA polymerase.
Wehrenberg
U
U
Institute for Hormone and Fertility Research, University of Hamburg, Germany.
Ivell
R
R
Jansen
M
M
von Goedecke
S
S
Walther
N
N
D000818:Animals; D001483:Base Sequence; D051838:COUP Transcription Factor I; D002417:Cattle; D002460:Cell Line; D003338:Corpus Luteum / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005260:Female; D051717:Fushi Tarazu Transcription Factors; D005786:Gene Expression Regulation; D006107:Granulosa Cells / Q000378:metabolism; D018398:Homeodomain Proteins; D008969:Molecular Sequence Data; D010053:Ovary / Q000378:metabolism*; D010121:Oxytocin / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011485:Protein Binding; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism; D011994:Recombinant Proteins / Q000096:biosynthesis; D054339:Steroidogenic Factor 1; D014157:Transcription Factors / Q000378:metabolism; D014162:Transfection
D051838:COUP Transcription Factor I; D004268:DNA-Binding Proteins; D051717:Fushi Tarazu Transcription Factors; D018398:Homeodomain Proteins; D018160:Receptors, Cytoplasmic and Nuclear; D011994:Recombinant Proteins; D054339:Steroidogenic Factor 1; D014157:Transcription Factors; D010121:Oxytocin