Nucleic Acids Research, 1994, Vol. 22, No. 9 1675-1680
© 1994
MOLECULAR BIOLOGY |
The promoter of the Xwnt-5C gene contains octamer and AP-2 motifs functional in Xenopus embryos
Hubrecht Laboratory Uppsalalaan 8, NL-3584 CT Utrecht, The Netherlands
*To whom correspondence should be addressed
Received January 5, 1994. Revised March 25, 1994. Accepted March 25, 1994.
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.