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pubmed:abstractText |
The Xwnt-5C gene is expressed in Xenopus embryos from the early gastrula stage onwards. The transcription of Xwnt-5C is regulated differentially with respect to transcript size, timing and localization. To gain insight into the generation of the Xwnt-5C expression pattern, we started to analyze the transcriptional regulation of this gene. We isolated Xwnt-5C genomic DNA sequences. By microinjection of chimaeric reporter constructs into Xenopus embryos we demonstrate that the upstream region contains a promoter functional in vivo. Of the several putative binding sites for trans-acting factors, present in a minimal promoter fragment, some have been studied in more detail. Mutations in an octamer motif and in an AP-2 consensus sequence interfere with the activity of the Xwnt-5C minimal promoter. In vitro binding assays with extracts from gastrula stage Xenopus embryos show that the octamer motif of the Xwnt-5C promoter can bind several Octamer binding factors, one of which is Oct1.
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