Regulation of apoptosis by dNP63 during Xenopus laevis development

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

Mar del Plata, Buenos Aires

Congreso; XLIII Reunion Anual Sociedad Argentina de Investigacion Bioquimica y Biologia Molecular; 2007

SAIB

 The p63 gene is a transcription factor and in mammals has two promoters that generate two types of protein isoforms, TAp63 and DNp63. The TA isoforms contain a transcription activation domain and are able to induce apoptosis. The DN isoforms lack the transactivation domain and can function as “dominant negative” proteins having an anti-apoptotic role. Although the p63 sequences are conserved among organisms, in Xenopus, only the orthologue of mammalian  DNp63g has been cloned and its role in development and apoptosis remains unknown. We analyzed the participation of DNp63 regulating apoptosis in Xenopus embryos. First, we analyzed the expression pattern of DNp63 using whole mount in situ hybridization. The main expression of DNp63 is located in the epidermis and also is detected as a defined line in the limit between neural folds and epidermis. Then, we proceeded to overexpress DNp63 in whole embryos and in animal caps to determine whether DNp63 was able to modify apoptosis. In both experiments, the TUNEL analysis showed that  DNp63 produced a decrease of apoptosis. Finally, we analyzed whether DNp63 was able to regulate the transcription of caspasas 2, 3 and 9, and Bcl2. Our results suggest that DNp63 is acting as an antiapoptotic factor during the development of Xenopus laevis regulating the transcriptions of some apoptotic and anti-apoptotic factors.