%0 Journal Article
%T Upstream Stimulating Factors 1 and 2 Enhance Transcription from the Placenta-Specific Promoter 1.1 of the Bovine Cyp19 Gene
%A Rainer F¨ırbass
%A Wolfgang Tomek
%A Jens Vanselow
%J BMC Molecular Biology
%D 2010
%I BioMed Central
%R 10.1186/1471-2199-11-5
%X The significance of the E-box was confirmed in cultured primary bovine trophoblasts. We enriched the E-BP from placental nuclear extracts using DNA-affinity Dynabeads and showed by Western blot analysis and supershift EMSA experiments that the E-BP is composed of the transcription factors upstream stimulating factor (USF) 1 and USF2. Depletion of the USFs by RNAi and expression of a dominant-negative USF mutant, were both associated with a significant decrease in P1.1-dependent reporter gene expression. Furthermore, scatter plot analysis of P1.1 activity vs. USF binding to the E-box revealed a strong positive correlation between the two parameters.From these results we conclude that USF1 and USF2 are activators of the bovine placenta-specific promoter P1.1 and thus act in the opposite mode as in the case of the non-orthologous human placenta-specific promoter.Ruminant species produce oestrogens in the cotyledons of their placentas. The functions of placental oestrogens change during gestation. First, together with progesterone, they are local activators of trophoblast growth and differentiation, acting via intracrine, autocrine or paracrine mechanisms (reviewed by [1]). Second, an oestrogen peak near term triggers endocrine and paracrine processes involved in the initiation of parturition, cervical softening and dilatation, and increasing myometrial contractibility (reviewed by [2]). In ruminants, low oestrogen levels and a reduced prepartal oestrogen peak are associated with an increased abortion rate, dystocia, and placental retention [3-5]. Oestrogens are synthesised by aromatisation of androgen precursors, which is catalysed by the enzyme aromatase cytochrome P450 (P450arom; EC 1.14.14.1). Oestrogen biosynthesis in various tissues depends on the expression of the P450arom-encoding Cyp19 gene, which involves tissue-specific promoters. Tissue-specific Cyp19 transcripts contain at their 5'ends unique untranslated exons, which, during processing, are spliced to a co
%U http://www.biomedcentral.com/1471-2199/11/5