Click here to close Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly. We suggest using a current version of Chrome, FireFox, or Safari.
Development 1997 May 01;1249:1733-43. doi: 10.1242/dev.124.9.1733.
Show Gene links Show Anatomy links

Activating and repressing signals in head development: the role of Xotx1 and Xotx2.

Andreazzoli M , Pannese M , Boncinelli E .

Xotx1 and Xotx2 are two Xenopus homologues of the Drosophila orthodenticle gene that are specifically expressed in presumptive head regions that do not undergo convergent extension movements during gastrulation. We studied the function of Xotx1 and compared it with that of Xotx2. Ectopic expression of each of the two genes has similar effects in impairing trunk and tail development. Experimental evidence suggests that posterior deficiencies observed in microinjected embryos are due to negative interference with convergent extension movements. Transplantations of putative tail-forming regions showed that, while Xotx1 overexpression inhibits tail organizer activity, Xotx2 overexpression is able to turn a tail organizer into a head organizer. Finally, Xotx1 and Xotx2 are activated by factors involved in head formation and repressed by a posteriorizing signal like retinoic acid. Taken together, these data suggest that Xotx genes are involved in head-organizing activity. They also suggest that the head organizer may act not only stimulating the formation of anterior regions, but also repressing the formation of posterior structures.

PubMed ID: 9165121
Article link: Development
Grant support: [+]

Species referenced: Xenopus laevis
Genes referenced: ag1 nog not otx1 otx2 tbxt

Article Images: [+] show captions