A dominant negative form of p63 is regulated by BMP4 and participates in Xenopus epidermis development

TRIBULO C.; AYBAR M.J.; SÁNCHEZ S.S.

Cancún, Mexico

Congreso; First Pan American Congress in Developmental Biology; 2007

Society for Developmental Biology, Latin American Society for Developmental Biology and Sociedad Mexicana de Biologia del Desarrollo

The ectodennal cells have to decide between two possible fates: the cells in the ventral side follow an epidermal fate while dorsal cells adopt a neural fate. The ectodenn patteming has been suggested to be under the control of BMP4 that induces epidennal fate and inhibits the fonnation of neural tissue. However, target genes regulated by BMP4 and their roles during the specification of epidermis are les s understood. p63, a.mem­ber ofthe p53 gene family, is required for mammalian epidennal development. In Zebrafish, the L1Np63 isofonn is a direct target ofBMP and is required for epidennal proliferation. InXenopus. only a cDNA corresponding to mammal L1Np63g has been identified and its role in development remains unknown. We analyzed the participation of L1Np63 in Xenopus epidennlli development and whether it is regulated by BMP4. First, the expression pattem of L1Np63 was analyzed and compared with the expression of FoxD3 and Sox2. By neurula stage, the main expression of L1Np63 is located in the epidennis aIíd also is detected as a defined line in the lirnit between neural folds and epidermis. Then, we overexpressed a dominant negative fonn o; BMP4 (CM-BMP4) in whole embryos and in animal caps. Tbe decrease in BMP4levels leaded to a lower expression of L1Np63 Finally, gain of function experiments of L1Np63 produced ae increase ofthe epidennal marker XK81A and a decrease of_ neural crest and neural plate markers FoxD3 and Sox2. TakeE together, our results suggest that L1Np63 participates in the re­gulation of ectodennal fates by promoting the epidermis spm­fication under the control ofBMP4.