INVESTIGADORES
AGÜERO Tristan Horacio
congresos y reuniones científicas
Título:
Banded hedgehog cell signaling pathway participates in Xenopus neural crest specification
Autor/es:
TRISTÁN H. AGÜERO; MANUEL J. AYBAR; SARA S. SÁNCHEZ
Lugar:
Guarujá, Brasil
Reunión:
Congreso; Second International Meeting of the Latinamerican Society of Developmental Biology; 2005
Institución organizadora:
Sociedad Latinoamericana de Biología del Desarrollo
Resumen:
Secreted morphogens of the Hedgehog (Hh) family in vertebrates are sonic hedgehog, cephalic hedgehog and banded hedgehog, and direct a wide range of developmental processes such as nervous system and limb patterning. Members of the Hh family bind to the transmembrane receptor Patched (Ptc) resulting in the derepression of the protein Smoothened (Smo) that regulates the activity of Gli family transcription factors. In this work we analyzed in detail the expression of banded hedgehog (bhh) and of the components of the intracelular signaling cascade during early development of Xenopus laevis embryos. The comparative in situ hybridization analysis showed that bhh is expressed during neurulation stages at the lateral border of neural plate in territories that overlap with the expression of Gli transcription factors and neural crest markers. In order to evaluate the participation of bhh pathway in neural crest development, we carried out a gain-of function approach by the microinjection of in vitro transcribed bhh mRNA in one blastomere of 4-8 cells embryos. At stages 14-17 embryos were fixed and processed for whole mount in situ hybridization. Results showed that an experimental increase in bhh signaling leads to an increased expression of neural crest markers (Slug, Snail, FoxD3) and Gli transcription factors. Additionally, the overexpression of Gli3 produced an expansion in neural crest territory mimicking the effect produced by bhh gain of function. On the other hand, the overexpression of a dominant negative construct of bhh (bhh rN-C) reduced the expression of neural crest markers, indicating that bhh signaling is required for neural crest specification. Our results show that bhh signaling and Gli transcription factors are participating in the early neural crest development.