Regulation of neural crest apoptosis in Xenopus laevis by XSlug and BMP4/Xmsx-1

CELESTE TRÍBULO; MANUEL J. AYBAR; SARA S. SÁNCHEZ; ROBERTO MAYOR

Marriott Copley Place, Boston, MA, USA.

Congreso; Society for Developmental Biology, 62nd annual meeting; 2003

Society for Developmental Biology

Apoptosis refers to the naturally occurring cell death that is part of the developmental program of an organism. This loss of cells can be fundamental to some developmental processes and serves many functions, such as sculpting or deleting structures, controlling cell number, and eliminating abnormal cells. Recently, an apoptotic program with high levels of cell death in the region of the neural crest was described in Xenopus. Our results confirmed that apoptosis is localized within the neural crest and that during neural crest development BMP4 and Xmsx-1 promotes apoptosis while XSlug acts as an antiapoptotic gene. In addition, we performed rescue experiments in animal caps. We found that in animal caps XSlug  and a dominant negative of Xmsx-1 (HDXmsx-1) are able to rescue the apoptosis induced by Xmsx-1. In order to analyze whether the apoptotic program affected by XSlug/Xmsx was dependent on the Bcl-2/Bax pathway we coinjected XSlug or HDXmsx-1 plus XBax, and Xmsx-1 plus XR11 (a Bcl-2 homologue). We found that XBax was able to rescue the antiapoptotic effect of XSlug and HDXmsx-1, while XR11 rescued the apoptotic effect of Xmsx-1. Finally, we analyzed by RT-PCR whether XSlug and Xmsx-1 were able to regulate the transcription of some apoptotic and antiapoptotic factors like caspasas and Bcl family members. Our results show that XSlug and HDXmsx-1 are able to control the transcription of caspases 2, 3, 6, 7, 9 and XR11.