A conserved 30 base pair element in the Wnt-5a promoter is sufficient bothto drive its' early embryonic expression and to mediate its' repression byotx2

We have characterised a short (30 base pair) element from the Xenopus Wnt-5 a promoter which is nearly identical to one located in the human Wnt-5a pro moter, and has the same position relative to the transcription start site. When placed in front of a LacZ gene, this element can reproduce the same ex pression pattern observed for Wnt-5a at the late gastrula stage. Further we show that gastrula stage Wnt-5a expression is repressed by otx2, something which is reflected by the mutually exclusive expression patterns of these two genes. The isolated promoter sequence contains an OTX- consensus bindin g site and its' activity in embryos is repressed by ectopically expressed o tx2. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.